Whether they’re lighting up the sky on the Fourth of July in the United States, welcoming the Lunar New Year across Asia, celebrating Diwali in India, marking Guy Fawkes Night in the United Kingdom, or ringing in the New Year in cities around the globe, fireworks have become one of humanity’s most recognizable forms of celebration.

For thousands of years (yes I know, thousands!), these brilliant displays have marked festivals, national holidays, religious traditions, and moments of joy shared by entire communities. Every summer, millions of people gather beneath the night sky to watch brilliant explosions of color. Reds bloom into blues. Gold crackles across the darkness. White stars shimmer before fading into smoke.

What you’re seeing is actually the result of carefully controlled chemistry and physics working together in a matter of seconds.

A brief history of fireworks

Long before fireworks became a centerpiece of celebrations around the world, they began with a simple but revolutionary discovery. Around the 9th century, Chinese alchemists searching for an elixir of immortality accidentally created one of history’s most influential chemical mixtures. By combining charcoal, sulfur, and potassium nitrate (also called saltpeter), they produced a substance that burned rapidly and released large amounts of hot gas and energy. Rather than granting eternal life, it produced spectacular explosions. This mixture became known as black powder, the world’s first chemical explosive (and something we still use today!)

Early fireworks were much simpler than the dazzling displays we know today. Bamboo stalks were thrown into fires because trapped air inside the hollow stems would heat up until the bamboo burst with a loud bang. Once black powder was discovered, people began filling bamboo tubes and paper containers with the mixture, creating louder explosions and eventually colorful displays. Fireworks were believed to frighten away evil spirits and bring good luck, making them an important part of festivals and celebrations.

How do they work?

Now, for modern fireworks:

When the fuse is lit, it ignites a small quantity of black powder called the lift charge, located at the bottom of the firework shell. As the black powder burns, it rapidly produces expanding gases. These gases build pressure inside a launching tube called a mortar, propelling the shell hundreds of feet into the air at speeds that can exceed 150 miles (240 kilometers) per hour. At the same moment, the lift charge ignites a second, carefully timed fuse inside the shell. This delay fuse continues burning while the firework climbs higher and higher into the sky. Its length is precisely engineered so the shell reaches the proper altitude before exploding. If the fuse burned too quickly, the firework would burst dangerously close to the ground. Too slowly, and the shell might burn out before reaching its peak.

Everything that happens next depends on this carefully timed sequence. In just a few seconds, the lift charge launches the shell, the delay fuse burns unnoticed inside, and the stage is set for the brilliant explosion that follows.

As the firework shell races upward, the delay fuse hidden inside continues to burn. For a few seconds, it seems as though nothing is happening. Then, at just the right moment, the fuse reaches the center of the shell and ignites another small charge known as the burst charge. Unlike the lift charge, whose job is to launch the shell into the air, the burst charge is responsible for creating the explosion that everyone watches from below.

The burst charge rapidly produces expanding gases that break the shell apart. At the same instant, it ignites dozens (or sometimes hundreds) of small pellets packed inside the shell. These pellets are known as stars (a terribly adorable name), and each one contains its own carefully designed chemical recipe that determines its color, brightness, burn time, and special effects.

As the stars are thrown outward in every direction, they continue burning through the air, creating the glowing points of light we see overhead. Depending on how the stars were arranged before launch, they may form perfect circles, cascading willows, sparkling chrysanthemums, or other intricate designs.

All of this happens in just a few seconds. What appears to be a single explosion is actually a carefully choreographed sequence of events, with every component igniting at precisely the right moment.

How do we get different colors?

The secret: atoms.

When a firework explodes, temperatures inside the burning stars can exceed 2,000°F (1,100°C). At these temperatures, electrons inside certain metal atoms absorb energy and move into higher-energy states. These excited electrons have to move and go somewhere.

As they return to their normal energy levels, they release their extra energy as tiny packets of light called photons. The wavelength of each photon determines the color we see. Because every element has a unique arrangement of electrons, each produces its own characteristic color when heated.

Some of the most common color-producing elements include:

• strontium → deep red

• calcium → orange

• sodium → bright yellow

• barium → green

• copper → blue

• potassium → violet

• magnesium, aluminum, and titanium → bright white sparks and flashes

Creating these colors is way harder than just mixing chemicals together. Each compound must burn within a specific temperature range to produce its brightest color.

Believe it or not, blue is one of the hardest colors to make. Copper compounds create beautiful blue light, but only if they burn at just the right temperature. If the firework burns too hot, the copper compounds break apart and the blue disappears. This is why vivid blue fireworks are considered one of the greatest technical achievements in modern pyrotechnics.

Okay but, how do they make the shapes?

Inside each shell, the stars are arranged around the burst charge in carefully planned positions. When the burst charge explodes, every star is pushed outward at nearly the same speed. Because they all begin from known positions, they preserve their overall arrangement as they spread through the sky.

This allows pyrotechnicians to create familiar patterns such as rings, chrysanthemums, peonies, palms, willows, and dahlias. More advanced shells can even produce hearts, smiley faces, stars, or company logos by arranging the stars into those shapes before launch.

Some fireworks become even more elaborate by containing multiple compartments. These shells explode in stages, releasing one pattern followed by another. Others contain smaller shells that burst after the first explosion, creating spectacular finales that seem to fill the sky.

Designing these shells requires careful calculations involving geometry, timing, chemistry, and physics. Even a slight change in how the stars are packed can dramatically change the final display.

A brighter future: environmentally friendly options

Fireworks can be fun but like many things us humans do… can be harmful to the environment.

After a display, smoke from the explosions can temporarily reduce air quality by releasing tiny particles known as particulate matter. These particles usually disperse within hours, but during large celebrations or in areas with little wind, they can contribute to short-term air pollution. Fireworks also leave behind bits of paper, plastic, cardboard, and metal that can become litter if they aren’t cleaned up.

The loud explosions can affect wildlife as well. Birds may suddenly take flight in the middle of the night, abandoning nests or becoming disoriented. Pets often experience anxiety during fireworks displays, and researchers have observed that some mammals alter their behavior for hours after loud celebrations. Because of these concerns, scientists and engineers have been working to develop cleaner alternatives.

One innovation is the use of low-smoke fireworks, which use different chemical formulations that produce less smoke and fewer airborne particles while still creating colorful displays. Some manufacturers have also reduced the use of certain metals to decrease environmental contamination after large events.

Another growing alternative is the drone light show. Instead of explosions, hundreds or even thousands of GPS-guided drones equipped with LED lights fly in carefully synchronized formations. These displays can create detailed animations, logos, animals, constellations, and even moving stories across the night sky. Because they produce no smoke and far less noise, drone shows are becoming increasingly popular for festivals, sporting events, and celebrations near sensitive wildlife habitats. In some cities, organizers have even begun combining fireworks with drone displays. They use fireworks for dramatic finales while relying on drones for much of the visual performance. This approach preserves the excitement of traditional pyrotechnics while reducing their environmental footprint.

I’ve seen posts recently that people are seeing fireflies out in their yards again. I love that people are noticing these things!

Fireflies are pretty, and they’re fun to chase around and try to catch while they blink on and off on a warm summer night. But how do they do that? If you sit there and think about it, you may start to wonder the how and the why like I did.

Did you know that there’s over 2,400 species of fireflies, and some even glow red or green?

Fireflies are among the most recognizable insects of summer, but their ability to produce light is actually a rare biological trait known as bioluminescence.

Bioluminescence occurs when a living organism generates light through a chemical reaction. While this phenomenon is common in some marine environments, it is relatively uncommon on land. Fireflies are one of the best-known terrestrial examples.

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The Chemistry of Firefly Light

The light produced by a firefly comes from specialized cells located in the lantern-like segments on the underside of its abdomen.

Inside these cells is a molecule called luciferin. (Cool name huh?)

When luciferin reacts with oxygen in the presence of the enzyme luciferase, energy is released in the form of visible light.

This process is more efficient than the old school incandescent light bulbs you may still have laying around at home. Nearly all of the energy generated is converted into light rather than heat, so biologists sometimes call it a “cold light”. Scientists actually estimate its over 90% efficient (wild!)

Why do fireflies flash their light?

At night when watching fireflies buzz around, you may notice they blink on and off. Most species use flashing as communication.

Each species has their own specific flashing pattern. Some produce a single pulse every few seconds, while others generate rapid sequences of flashes. These patterns help males and females locate members of their own species during the breeding season.

Here’s what you're watching: the males fly while flashing, and the females respond from the vegetation below with a species-specific signal of their own. The timing and pattern are like their ID.

In North America alone, more than 150 species of fireflies use different flash patterns to communicate.

Firefly light also serves another purpose - protection from predators.

Producing light tells the predators such as birds, spiders, and small mammals that they would taste gross. The chemical that makes them taste bad is called lucibufagins. Even firefly larvae glows.

Now we know why they glow… but how do they turn it on/off?

Okay, we learned that fireflies glow because of a chemical reaction (luciferin + oxygen + luciferase = visible light).

But if the chemicals are always there, why aren’t they always glowing?

After decades of scientists struggling to answer this, now the key appears to be oxygen. Now scientists believe that fireflies regulate the flow of oxygen into their photocytes (light producing cells) with remarkable precision. When oxygen levels rise within the light organ, the chemical reaction proceeds rapidly and a flash occurs. When oxygen levels fall, the reaction slows and the light disappears.

This oxygen control happens within a fraction of a second.

The light-producing organ itself is highly specialized. (thanks natural selection! -firefly, probably)

The lower portion contains the photocytes (light cells). Above these cells is a reflective layer rich in uric acid crystals. Rather than allowing light to scatter in all directions, it works somewhat like a mirror inside a flashlight and directs the light outward. The outermost layer is more transparent than the rest of the exoskeleton, allowing light to pass through efficiently.

Fireflies are nature’s lightbulb

Today, firefly flashes represent a combination of chemistry, behavior, and evolution. What appears to be a simple blinking light is, upon closer inspection, the result of a highly specialized biological system that allows these insects to communicate, avoid predators, and reproduce.

If you haven’t seen many fireflies around your home and want to see more, see this article from the U.S. Fish and Wildlife Service here.

Next time you see fireflies flashing, keep in mind all the chemistry happening. I tend to always be in awe of the world around me as I learn more about it with my readers.

Obviously, metamorphosis. But what actually is metamorphosis? Like, what really happens in there?

We all accept the fact that caterpillars become butterflies, but I have personally never looked into how exactly it happens.

Before we get into specific cool bugs, let’s get a general idea or reminder of what metamorphosis is. Even for me as a biologist, it has been a long time (20 years maybe?) since I studied metamorphosis.

Biological metamorphosis is, by definition: a process where an animal physically develops and changes its body structure as it matures.

There are two kinds used for insects: complete metamorphosis and incomplete metamorphosis. For other animals, such as frogs, scientists just say they “undergo metamorphosis”.

Complete Metamorphosis

The animals (yes insects are animals) that perform complete metamorphosis have life cycles like the one above. Adults lay eggs, the eggs hatch into larvae, then the larvae go into a pupa stage where it is mainly inactive, and finally bursts out as a beautiful new form.

Maybe you remember in elementary school, your class raised caterpillars into butterflies and then released them. I sure do. My love for science developed very early.

The types of animals that undergo this are almost primarily insects, such as:

• butterflies

• moths

• skippers

• beetles

• flies

• bees

• wasps

• ants

• fleas

Example: Butterflies

Did you know that butterfly eggs have a yolk?

After they hatch into larvae, their main job is to EAT and shed their layers as they grow, and each time they do this its called an instar. We know these larvae as caterpillars.

Next stage: the pupa where they… well, pupate.

Time for the big questions! What happens in a chrysalis? Do caterpillars really turn into “soup” or “goo”?

Actually, we have found through CT imaging that most of their important bits don’t dissolve completely and turn into soup. The tracheal tubes that let them breathe don’t dissolve. The gut (stomach, etc.) is also still there, but shrinks. Parts of their central nervous systems stay the same as well. Below are the CT images.

The blue lines are the tracheal tubes. The red is their guts. The green things are… future wings! kind of!

Those green things are blobs of tissue that will turn into wings during metamorphosis.

Scientists call these structures imaginal discs.

Despite the somewhat intimidating name, imaginal discs are simply small clusters of cells that have been hiding inside the caterpillar since it first hatched from its egg.

In fact, the caterpillar contains several imaginal discs, each destined to become a different part of the adult butterfly.

These structures quietly wait while the caterpillar is busy stuffing itself and growing, and then they activate when hormones throw a signal. In the process, some tissues get broken down and the nutrients recycled for other structures (like wings).

It’s cool to know that the caterpillar has been carrying the blueprint for its future self since the day it hatched. (Something something poetic words about how we all have the blueprint for the future us inside something something)

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Quick reminder:

Frogs do not undergo complete or incomplete metamorphosis. They just undergo metamorphosis.

Complete/incomplete metamorphosis is reserved for insects.

Frogs begin life as eggs, hatch into tadpoles with gills and a tail, and eventually develop legs and lungs while its tail is absorbed.

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Incomplete metamorphosis

Incomplete metamorphosis only has 3 life stages:

Egg → Nymph → Adult

Insects that fall under this category don’t have a pupal stage. Instead, the young insects, called nymphs, generally resemble smaller versions of the adults. As they grow, they molt their exoskeleton several times until they reach adulthood.

Butterflies are a popular example, but there’s an example of incomplete metamorphosis I’m sure you’ve heard of or seen in nature.

Dragonflies begin life as aquatic nymphs living underwater. They already have many of the characteristics of an adult dragonfly, but they lack fully developed wings and reproductive organs. After a series of molts, the nymph climbs out of the water, sheds its final skin, and emerges as an adult dragonfly.

I don’t know about you… but dragonfly nymphs are scary looking.

Jump scare warning!

Some examples of common insects that undergo incomplete metamorphosis:

• damselflies

• grasshoppers

• crickets

• katydids

• locusts

• praying mantises

• stink bugs

• assassin bugs

• cicadas

• aphids

• cockroaches

• termites

• earwigs

• walking sticks

• leaf insects

Like frogs..

Here are some animals that undergo just metamorphosis and aren’t categorized with insects:

• toads

• salamanders

• axolotls

• newts

• moon jelly

• sea stars (starfish)

• sea urchins

• barnacles

• crabs

• lobsters

• eels

Summary

Metamorphosis is one of nature’s most remarkable solutions to survival. It allows an animal to spend different stages of its life doing different jobs. Whether its a caterpillar emerging from a chrysalis, a dragonfly climbing from a pond, a tadpole becoming a frog, or a sea star transforming beneath the ocean’s surface, each undergoes a journey that completely reshapes its body and way of life.

So many animals have such surprising life cycles, so much so that they can become something entirely new.

So.. do caterpillars turn into soup? The answer is not entirely, but basically yes. Butterflies emerge from soup.

Have a question about anything science related? Feel free to ask me!

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Do you notice the birds, crickets, squirrels, and other wildlife going silent before a storm hits?

Some people even claim to feel it. They may be able to. Some animals are very sensitive to the pressure changes before a storm.

Birds may move lower into trees or seek shelter. Insects often stop flying because unstable air currents and changing humidity make movement more difficult. Small mammals become less active and retreat toward cover.

As storms approach, entire ecosystems can temporarily shift from activity toward caution. We often forget that we are also part of the ecosystem.

For most of human history, paying close attention to nature was important for survival. Human ancestors constantly watched animal behavior, wind patterns, clouds, and environmental sounds for signals about approaching danger.

A sudden silence in birds or insects could mean a predator nearby. Abrupt changes in wind or animal movement could signal storms, fires, floods, or other environmental threats. Researchers believe humans became highly attuned to environmental pattern recognition because noticing subtle changes increased survival chances over thousands of years.

That may be part of why the silence before storms still feels unsettling now.

Our brains are still wired to recognize nature’s behavior as warning signs.

Storms change behavior before it even starts raining

Many organisms can detect approaching storms earlier than humans can.

One major reason is barometric pressure.

As storms develop, atmospheric pressure drops. Certain birds and insects are capable of sensing those pressure shifts long before rainfall begins.

Some seabirds have even been observed changing feeding behavior hours before major storms arrive.

Insects respond strongly as well.

Mosquitoes fly lower during low-pressure conditions. Bees often return to hives earlier before rainstorms. Cicadas and crickets may reduce activity as humidity and atmospheric instability increase.

Storms create environmental conditions that make communication, flight, and movement more difficult or dangerous.

So ecosystems become quieter not because life disappears, but because many organisms are temporarily conserving energy and seeking shelter.

The smell of storms

There is another clue that a storm is approaching.

The smell.

Many people notice that the air smells different before a thunderstorm arrives. Fresher almost. Sometimes this is caused by increasing humidity, which makes environmental odors easier for us to detect. Strong thunderstorms can also produce ozone, a gas with a sharp, clean scent that some people can smell before rain begins.

After rain starts falling, another familiar smell often appears.

Scientists call this scent petrichor. I know almost everyone now has heard of petrichor. It tends to be romanticized in online spaces.

What you may not know is this: Petrichor is created when raindrops strike dry soil and vegetation, releasing compounds into the air. One of the most important of these compounds is geosmin, a molecule produced by soil-dwelling bacteria.

Humans are remarkably sensitive to geosmin. We can detect it at extremely low concentrations, even when only tiny amounts are present.

Scientists are not entirely sure why we are so good at smelling it, but some researchers think the ability may have helped our ancestors locate fresh water or recognize incoming rainfall.

For most of human history, people paid much closer attention to nature than most of us do today.

For most of human history, we were reading nature because our survival depended on it. Its not a lost art. We can still do it.

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Storms don’t just affect ecosystems—they help shape them

Although storms can damage trees and flood landscapes, they also play important ecological roles.

Rainfall replenishes lakes, rivers, ponds, and groundwater that countless species depend upon. Temporary pools created by storms become breeding habitats for frogs, toads, salamanders, insects, and other organisms.

Many plants rely on seasonal rainfall patterns to trigger growth, flowering, or seed germination.

Some desert species can remain dormant for months or even years before becoming active after a significant rainfall event.

Storms also help redistribute nutrients throughout ecosystems.

Heavy rain carries organic matter into streams and wetlands, where it becomes food for microorganisms, insects, and aquatic animals. Strong winds can disperse seeds, pollen, and fungal spores across large distances.

Lightning helps fertilize the Earth

Even lightning contributes to the health of ecosystems. It makes something for free that we use in our fertilizers.

Earth’s atmosphere is made up of about 78% nitrogen gas. The challenge is that most living organisms cannot use nitrogen in that form. It needs to be made into the bioavailable form.

Plants need nitrogen to build proteins, DNA, and chlorophyll.

Lightning helps solve that problem.

The tremendous energy released during a lightning strike breaks apart nitrogen molecules in the atmosphere. These nitrogen atoms can then combine with oxygen and eventually dissolve into rainwater.

When that rain reaches the ground, the nitrogen enters soils where plants can absorb and use it.

Scientists estimate that lightning naturally fixes millions of tons of nitrogen worldwide each year.

The quiet before a storm

The next time a summer thunderstorm approaches, try paying attention.

Listen to the birds. Notice whether the insects seem quieter than usual.

Watch how the wind changes and how the leaves move. The wind may even turn colder before a storm hits.

What sounds like quiet is often biology at work.

Every few years, the phrase starts showing up everywhere.

Meteorologists mention it during weather forecasts. News headlines warn about it before hurricane season. People start blaming heat waves, flooding, droughts, wildfires, and strangely warm winters on something called El Niño.

But what actually is it?

Put simply… It’s a pattern.

More specifically, it is a large-scale warming of part of the Pacific Ocean that changes weather patterns across huge portions of the planet.

Huh? How does that work? How could warmer water in one ocean affect weather thousands of miles away?

The answer is.. drumroll Earth’s climate systems!

These systems are deeply connected. Water carries heat exceptionally well (the highest specific heat capacity of all liquids to be exact), and the ocean currents move that heat around the planet. The atmosphere responds to ocean temperatures. Wind patterns shift, and storm tracks move.

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The Pacific Ocean Can Predict the Weather

Okay well, not exactly.

Under normal conditions, strong winds called trade winds blow across the tropical Pacific Ocean from east to west. These winds constantly push warm surface water towards Asia and Australia. Meanwhile, colder water rises near the western coast of South America to replace it.

The rising cold water is called upwelling, and it is incredibly important because it brings nutrients from deep in the ocean up toward the surface. Those nutrients support plankton, fish populations, seabirds, and entire marine ecosystems.

Normally the Pacific Ocean is balanced. Warm water in the western Pacific, colder water in the eastern Pacific. Winds keeping the water moving.

What does that have to do with El Niño?

The trade winds slow down.

Sometimes only slightly, other times dramatically.

Without those strong winds constantly pushing warmer water west, it begins drifting back east across the Pacific Ocean.

At the same time, the cold-water upwelling near South America weakens.

Suddenly, parts of the Pacific that are usually cooler become unusually warm.

The warm water then affects the atmosphere above it, which changes where air rises, where storms form, and where rain falls.

This Affects the Whole World

We all share one atmosphere.

Weather systems are constantly moving heat and moisture around the globe. So when a massive section of the Pacific Ocean changes temperature, the atmosphere reacts.

• jet streams shift

• rainfall patterns shift

• storm development changes

Those changes can be felt for thousands of miles.

How does this affect the United States?

Depends on where you are!

The Southern United States: Wetter & Stormier

• heavier rainfall

• stronger thunderstorms

• increased flooding risk

• humid, unstable weather patterns

Since warm air holds more moisture, storms can dump enormous amounts of rain very quickly.

The Southwest: More Monsoon Activity

In places like Arizona and New Mexico, El Niño can sometimes strengthen late-summer monsoon patterns.

That may mean:

• more thunderstorms

• sudden desert flooding

• dramatic lightning storms

• bursts of rain after long stretches of dry heat

This is a way we get desert blooms!

California: Complicated, As Usual

California weather during El Niño years gets a lot of attention, but it is not as simple as “El Niño means rain.”

Strong El Niño patterns are often linked to wetter winters later in the year, but summers can still remain extremely hot and dry.

In some cases, increased plant growth from earlier rain eventually dries out and becomes wildfire fuel.

So oddly enough, more rain can sometimes contribute to future fire risk.

The Midwest and Plains: Severe Weather Potential

The central United States often sees highly unstable weather patterns during El Niño development.

That can include:

• heat waves

• severe thunderstorms

• large hail

• sudden shifts between drought and flooding

When Gulf moisture collides with hot summer air over the Plains, the atmosphere can become extremely energetic.

What about hurricanes?

This is one of the biggest reasons meteorologists start talking about El Niño every summer.

El Niño tends to increase wind shear over the Atlantic Ocean. Basically, winds high in the atmosphere become more disruptive to developing tropical systems.

That often means:

• fewer Atlantic hurricanes overall

• storms struggling to organize

• less hurricane intensification

But importantly: fewer hurricanes does not mean no hurricanes.

A single storm can still become devastating.

El Niño Around the World

The effects are not limited to the United States.

• Australia and parts of Southeast Asia often become hotter and drier, increasing drought and wildfire risk.

• Western South America may experience flooding and landslides.

• India’s monsoon system can weaken.

• Some parts of Africa flood while others dry out.

• Warmer water can disrupt fisheries, coral reefs, and marine food webs that rely on colder nutrient-rich currents.

Every couple of years, the Earth reminds us how connected all of it is.

Even humans rearrange entire landscapes around flowers without thinking much about it. We plant them outside homes, breed them into new colors, use them for food, medicine, perfumes, dyes, oils, and agriculture. We gift them to one another for holidays and special occasions.

All because plants evolved a structure so effective that it reshaped ecosystems across Earth.

Flowers may look soft and temporary, but biologically they are one of the most successful evolutionary inventions ever created.

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Flowers were an evolutionary breakthrough

Before flowering plants existed, many plants reproduced in ways that were far less efficient.

Some depended heavily on water because sperm cells physically needed moisture to reach egg cells. Reproduction became difficult in dry conditions or unpredictable environments.

Flowering plants changed the game entirely.

Instead of depending only on water or chance, plants evolved structures capable of recruiting help from animals and environmental forces around them.

This gave flowering plants enormous advantages.

They could reproduce across greater distances, spread into new environments, and exchange genetic material more efficiently.

Over time, flowering plants (called angiosperms) spread across most of the planet.

Today, they dominate forests, grasslands, farms, wetlands, gardens, and cities.

Flowers are communication systems

A flower is not just pretty, it also talks to other things that are alive.

Petals help attract attention visually. Scents move chemical signals through the air. Nectar rewards pollinators for visiting.

Some flowers even produce ultraviolet markings invisible to humans but highly visible to bees. Here’s some examples:

To pollinators, flowers often contain directional patterns that function almost like runway lights guiding them toward food.

Different pollinators are attracted to different traits.

For example:

• hummingbirds are often drawn to red tubular flowers

• moth-pollinated flowers are commonly pale and strongly scented at night

• flies are sometimes attracted to flowers that smell like decay

• bats prefer large flowers with strong odors and abundant nectar

Some orchids evolved to resemble female closely enough to trick male insects into attempting to mate with the flower.

Sounds absurd, but the flower above is the bee orchid. It mimics bees to attract the males to it.

Evolution tends to favor whatever works.

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Flowers can track environmental change

Plants constantly gather information from their surroundings despite lacking brains or nervous systems.

They can detect:

• day length

• moisture

• gravity

• temperature

• touch

• light direction

Flowering usually begins only after very specific environmental conditions are met.

Some plants flower as daylight hours increase in spring. Others require exposure to winter cold first. Cold-triggered flowering process is called vernalization.

Without, some plants may continue growing normally but fail to flower later. So, when spring arrives, flowers are not suddenly appearing out of nowhere.

Plants have often been preparing for months.

Reproduction is expensive

Producing flowers requires enormous energy investment from plants.

Pigments, sugars, nectar, scent molecules, and reproductive tissues all cost resources to build and maintain. That’s why flowers often exist for only short periods of time.

Once pollination and fertilization occur, the plant redirects energy toward the next phase:

• seed production

• fruit development

• embryo protection

Petals wilt because the flower’s primary job in complete.

A flower may seem delicate, but biologically it functions more like a temporary reproductive structure optimized for efficiency.

Fruit begin as flowers

One of the strangest biology facts is that fruits are mature ovaries surrounding seeds.

Apples, peaches, tomatoes, cucumbers, pumpkins, peppers, and avocados all develop from flower tissues after fertilization occurs.

The plant then uses fruit to help spread offspring into new environments.

Different fruits evolved different strategies:

• sweetness encourages animals to eat them

• hooks attach to fur

• floating fruits travel through water

• dry seed pods burst open mechanically

Plants solved movement without ever evolving muscles.

Flowers helped shape modern ecosystems

Flowers did not evolve alone.

Pollinators and flowering plants changed one another over millions of years through coevolution.

Flower shape influenced pollinator anatomy. Pollinator behavior influenced flower color, scent, bloom timing, and structure.

Over time, ecosystems became deeply interconnected through these relationships.

This is why pollinator decline today affects much more than just “flowers” or “bees”.

It impacts:

• seed production

• agriculture

• biodiversity

• food webs

• ecosystem stability

Flowering plants quietly support huge portions of life on Earth.

The world changes every spring because of flowers

Spring is not simply plants “coming back”.

It is an enormous coordinated reproductive season happening across ecosystems.

Flowers bloom. Pollinators emerge. Seeds begins developing. Animals breed. Food webs accelerate.

Underneath all the color and good weather is a massive biologist system preparing the next generation of life.

And most of it happens quietly enough that we barely notice it.

Every spring, the world turns that yellowish green color we’ve all come to know.

Cars collect a fresh coat overnight. Sidewalk cracks turn pale green. It seems like trees threw up clouds.

For most, pollen is an inconvenience. Allergies, itchy eyes, sneezing. But biologically, pollen is one of the most important structures plants ever evolved.

Without it, forests wouldn’t heal after a fire or logging. Flowers wouldn’t seed every spring. We wouldn’t know the joys of fruit. Entire ecosystems would collapse, and humans would not have made it this long.

What is pollen?

Pollen is a highly specialized reproductive structure carrying genetic material from one plant to another.

It is astonishingly engineered.

Pollen is the male gametophyte (big fancy science word for part) of seed plants. It forms inside the anthers of flowers through meiosis, the same process that creates eggs and sperm in humans and animals.

Each microscopic grain contains sperm cells. But unlike animal reproduction, plants can’t really move to find one another. They had to get creative and find a way to get their genetic material across a distance while surviving wind, rain, UV radiation, and time.

Natural selection landed on pollen. It gets the job done, and allows organisms to survive to the next generation (the whole point of natural selection btw).

A single grain of pollen is incredibly small, but under a microscope it becomes surprisingly complex. Different plant species produce different shapes, textures, and surface patterns. Some pollen grains are smooth, others are spiked, ridged, or net-like.

Those structures all have a specific purpose. They help the pollen attach to pollinators, move through air currents, or survive harsh environmental conditions.

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Pollen has… armor?

The outer wall of pollen is made of sporopollenin, one of the toughest materials known.

It resists:

• heat

• drying out

• UV radiation

• chemical damage

• decay

Scientists even don’t fully understand how sporopollenin is made because of how chemically resistant it is.

This durability is also why pollen survives in the fossil record for millions of years. Ancient pollen trapped in lake sediments, peat bogs, and ice cores can still be identified today.

We have evidence of ancient ecosystems because of this. Neat, right?

Scientists can examine layers of fossilized pollen and determine:

• what plants once lived in an area

• when forests expanded or disappeared

• how climates changed over time

This field is called palynology.

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How pollen reaches another plant (dispersal)

Once pollen leaves the anther, its journey depends entirely on the species of the plant.

Some plants rely on wind, others on animals, some even on water.

These strategies produce very different kinds of pollen.

Wind-pollinated plants

Trees like oaks, pines, and grasses release enormous amounts of lightweight pollen into the air. Its not very efficient.. But they operate on probability.

Most wind-blown pollen never reaches its target, but plants compensate for that by making an absolute metric crap-ton of it.

If you’ve got spring allergies, its probably because of these guys. They’re:

• lightweight

• small

• airborne for long periods

• easily inhaled by humans

On heavy pollen days, the air can literally become saturated with millions of microscopic grains.

That yellow dust coating your windshield could be pollen from dozens of plant species.

Animal-pollinated plants

Other plants take a much more targeted approach.

Instead of releasing pollen randomly, they recruit animals to transport it directly between flowers.

This is where pollinators like Apis mellifera (Western honey bee) become important.

These plants often produce:

• sticky pollen

• heavier grains

• bright flowers

• nectar rewards

• scents visible or detectable to pollinators

As bees, butterflies, moths, beetles, birds, or bats feed on nectar, pollen sticks to their bodies and travels with them to the next flower.

This relationship is an example of coevolution. Over millions of years, plants and pollinators shaped each other’s evolution.

Some flowers have even specialized for specific pollinators.

• tubular flowers for hummingbirds

• night-blooming pale flowers for moths

• strong-smelling flowers for beetles

What happens when pollen lands?

Landing somewhere is only the first step.

If the species match correctly, the pollen grain begins growing a microscopic tube downward through the style of the flower.

This is called a pollen tube.

The tube acts like a mail system, transporting sperm cells directly to the ovule.

Then magic happens: double fertilization

One sperm cell fertilizes the egg cell and forms the embryo. The second sperm cell helps create endosperm, the nutrient-rich tissue that feeds the developing seed.

Takeaway

Pollen looks simple, but its actually biologically complex and awesome at surviving almost anything.

And remember, it’s usually not the pretty flowers’ pollen that’s making you feel sick, because they have sticky pollen. It’s tree and grass pollen that can go up your nose.

After months of dull colors, bare branches, and shorter days, everything seems fresh and happy once spring hits. Trees leaf out or start budding. Grass is back. The local war turns green again.

People also report feeling calmer, lighter, more stable.

That response is biological!

Your brain is wired to like green

Humans didn’t evolve in cities, those are relatively new to us. We involved in environments where survival depended on reading the landscape. Green vegetation historically signaled something important: water, food, and/or safety a.k.a. the biophilia hypothesis.1

Because of this, we’re still hard-wired to interpret green spaces as low-threat environments.

Studies in environmental psychology show that exposure to green environments:

• lowers cortisol (stress hormone)

• reduces heart rate and blood pressure

• improves attention and cognitive performance

• decreases symptoms of anxiety and depression

In one widely cited study, participants recovering from stress showed faster physiological recovery when viewing natural scenes comparted to urban one.2 Larger reviews have found consistent links between access to green space and improved mental health outcomes.3

Uh okay but what does this mean? Basically, science has shown that green calms people down. You should share a little green with someone you love today.

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Green affects your visual system differently

Green light sits in the middle of the visible spectrum (~495-570 nm), which makes it easier for the human eye to process compared to more extreme wavelengths.4 (Fun fact: did you know fuchsia is not a color?)

Our eyes and brains are tired. They’re constantly working to interpret visual input. When that processing demand is lower, it contributes to a subtle sense of ease and safety.

Time for spring reset

As daylight in spring increases:

• your brain reduces melatonin

• increases serotonin

• helps regulate dopamine

These shifts are directly tied to light exposure and seasonal changes in day length. At the same time, natural light helps stabilize your circadian rhythm, which affects sleep. energy, and mood.5

Why spring feels so magical

The “nature effect” often explained through the framework of biophilia and Attention Restoration Theory helps us feel better.

The idea is simple. Natural environments allow your brain to recover from constant, directed focus by engaging a more passive, low-effort type of attention. It shows up in ways we can measure, like through improved concentration, reduced mental fatigue. and better overall cognitive performance after time spent in green spaces.

Spring follows a period of lower light availability, reduced outdoor activity, and for many people, lower mood states. Seasonal mood variation, including Seasonal Affective Disorder (aka the Big Sad), is strongly linked to light exposure. (You may have been advertised a “sunlight lamp” over the winter - I sure was).

When the green comes back, its paired with:

• longer days

• warmer temperatures

• increased biological activity

Your brain registers this combination as a shift toward more stable, resource-rich conditions.

Green should be your favorite color

Green has always been one of my favorites, but now as an adult, I love all shades of it.

Did you know humans can see more shades of green than any other color?6

Studies have shown that just looking at pictures of green things can make you feel better. Maybe make an effort to go outside and notice all the green sometime this week. If you’re unable, here’s some extra green for you:

Tweet, chirp, scream, hoot, ribbit. All that hootin’ and hollerin’.

Mornings aren’t quiet anymore like in the dead of winter.

Nothing like the cacophony of spring!

Okay but why? What changes?

As days get longer, activity increases across a lot of species at once.

Happy breeding season, baby!

And what do you need to breed?

That’s right…… communication. ;)

Per one of my last emails,

it doesn’t start with temperature. Common misconception.

Similar to plants, it’s actually the photoperiod (or the length of daylight).

Many organisms track day length using internal biological clocks.

In plants, that signal controls:

• dormancy breaking

• leaf & flower production

• hormone activation

In animals, that same signal affects the endocrine system.

What happens in the endocrine system

As daylight increases, light information is processed through the brain (via the hypothalamus), which influences hormone release.

This activates the hypothalamic-pituitary-gonadal (HPG) axis.

Leading to:

• increased testosterone in many male birds

• development of reproductive organs

• changes in behavior (including hootin’ and hollerin’ because they erm.. want to find a mate)

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Birds

Birdsong is a reproductive behavior linked directly to hormone levels.

As testosterone rises:

• song frequency increases

• song complexity can increase

• territorial behavior becomes more intense

Research has shown that:

• males that sing more consistently are more likely to attract mates

• song can signal both health and territory quality

Why do they sing so loud in the mornings?

Unlike humans, birds actually don’t have a morning testosterone spike. Their testosterone levels stay elevated all spring.

It’s actually the most efficient time to communicate. Birds are trying to defend their territory and attract mates.

Morning is strategic because other birds are listening, signals travel father, and competition is high.

There’s actually physics involved in it too.

Sound travels better in the morning because:

• cooler, denser air helps sound carry farther

• winds are usually calmer → less distortion

• there’s less background noise

Frogs

Frogs rely more on temperature thresholds and moisture availability.

Calling behavior is tied to breeding.

Each species has:

• a specific frequency range

• a defined call pattern

• timing that reduces overlap with other species

This is part of acoustic niche partitioning, which prevents signals from getting lost.

Insects

Insects add to the musical score of spring, because as temperatures rise:

• metabolic rates increase

• movement increases

• communication increases

Many insects use stridulation (rubbing body parts together) or wing vibration to produce sound.

Some are signals for mating, territory, or warnings.

The big picture

Plants respond to increasing daylight by:

• initiating growth

• producing leaves and flowers

• increasing available energy in ecosystems

I go more in depth on what plants do in spring and what makes them start popping off here if you’re interested:

This is part of phenology (the timing of seasonal biological events).

Animals depend on the timing of plants.

Reproduction is most successful when food is available, conditions are stable, and offspring can survive.

Summary

Spring is SO loud because multiple systems are working at the same time:

• photoperiod increases

• plants enter active growth

• hormone systems activate in animals

• breeding behavior begins

• communication increases

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What even is Earth Day?

To start, it’s observed every year on April 22nd.

It’s meant to bring attention to the environment! How it works, how we impact it, and how we can take better care of it.

But first it was a response.

How it began

In the 1960s, environmental problems were becoming harder to ignore:

• air pollution from cars and industry

• rivers contaminated with waste

• wildlife populations declining

At the time, there were very few regulations protecting the environment. Then, in 1969, a massive oil spill off the coast of California made national headlines.

That moment helped push environmental concerns into public focus.

In 1970, U.S. Senator Gaylord Nelson organized the first Earth Day.

Over 20 million people participated. (wow!)

It became one of the largest public demonstrations (or, a protest) in U.S. history.

What changed

The first Earth Day led to real policy changes.

In the years that followed, the U.S. established:

• the Environmental Protection Agency (EPA)

• the Clean Air Act

• the Clean Water Act

• the Endangered Species Act

Earth Day now

Today, Earth Day is recognized and celebrated globally. More than 190 countries participate.

The purpose is awareness and action.

Why it still matters

Environmental protections may be changing in the U.S. with the current administration.

As of April 21, 2026, here are a few areas where environmental protections are being adjusted or weakened:

• NEPA

  → projects like pipelines, drilling, and construction may go through faster or less detailed environmental review

• Clean Air Act

  → some rules limiting greenhouse gas emissions are being rolled back or reduced

• Air toxics

  → limits on certain pollutants from power plants are being loosened

• Clean Water Act

  → fewer waterways may qualify for federal protection depending on definitions

• Endangered Species Act

  → protections for threatened species and their habitats may become more limited or case-by-case

• Wildlife protections

  → more flexibility is being given for development in areas where protected species live

• Chemical safety rules

  → some requirements for preventing industrial chemical accidents may be scaled back

Simple things you can do

Plant some native flowers for your local pollinators.

Pick up litter outside.

Visit a park or nature center to learn more.

Participate in a local clean-up event.

Share what you know.

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The point

Environmental health depends on multiple systems working together:

• clean air supports respiration

• clean water supports life and ecosystems

• soil health supports plant growth

• biodiversity supports stability

All of it is connected. and it’s all worth paying attention to.

Can you smell it?

The air is heavier. Temperatures are going through mental breakdowns.

That’s right, severe weather season is ramping up again.

Its the most wonderful time of the year specifically because of the wonder it invokes in me. A wonder that nature can be so powerful, through how the atmosphere works.

The atmosphere is like an onion - it has layers

A common assumption is that storms form simply because it gets warmer.

That’s only part of it.

During spring, 3 main types of air begin to overlap in the central plains:

• warm, moist air moving north from the Gulf of Mexico

• cold, dry air moving down from Canada

• hot, dry air moving in from the west

These layers stack, slide, and collide constantly. This creates instability, which is needed to build storms.

Wind matters more than you think

Not all storms become severe.

So what changes?

One of the most important changes is coming called wind shear. This means wind speed and direction change as you move higher into the atmosphere.

Through this process, storms can begin to:

• tilt instead of collapsing

• organize instead of dissipate

• rotate instead of staying linear

When rotation becomes strong and sustained, a storm can develop into a supercell. This is the type of storm most associated with tornadoes.

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Why this region?

If you live in the Central Plains or the Midwest, you’re used to it. Crack open a beer or soda and plop into a chair on the porch or garage to watch them come in.

It’s a part of life. But there’s a reason why it happens here.

There are very few natural barriers here to disrupt airflow. So those three air masses can meet freely and often. That repeated interaction creates a pattern we refer to as Tornado Alley.

To be more specific, we get:

• direct access to Gulf moisture

• cold, dry air masses from Canada

• dry air from the Southwest (the “dryline”)

• flat terrain

• position of the jet stream

Why now?

Spring is when these ingredients overlap the most.

• the Gulf is warming → more moisture available

• winter air still lingering → cold air hasn’t fully retreated

• the jet stream is still active → strong winds aloft

So the atmosphere ends up with:

• energy (warm air)

• contrast (cold vs warm)

• motion (wind shear)

All at once.

All the ingredients for a severe weather recipe that could cook up disaster.

How do I know a storm is coming?

Pay attention to:

• the birds

• the insects

• a sudden shift or drop in temperature

• winds changing direction quickly

• the sky

• your favorite weather app

As they say, be prepared, not scared.

Reminder of the differences between warnings/watches:

• A tornado watch → watch for a storm, it could happen. No need to take shelter but pay attention to the skies.

• A tornado warning → warning, tornado coming towards you now, take cover

Never stop under an overpass if there’s a tornado coming. The winds get stronger under there!

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The shift isn’t always obvious.

Around March 20th each year, life seems to wake up again.

The spring (or vernal) equinox marks the moment when the Sun sits directly above Earth’s equator. As a result, day and night are nearly equal in length across the planet.

This marks the beginning of when the Northern Hemisphere gets more daylight, and I start to feel alive again.

If you take the time, you may notice:

• sunsets lasting longer

• sunrises earlier

• more light throughout the day

Its actually the shift in light, not temperature, that drives a lot of the changes we associate with spring.

Light drives away the dark

A common misconception is that plants begin growing because its getting warmer out. Makes sense, right?

That’s only a piece.

Plants rely primarily on light timing, a period known as photoperiodism.

Through this process plants are measuring:

• how long the day lasts

• how long night lasts

• the quality of light (especially red light wavelengths) (plants are green because they absorb red light and reflect green light)

As days become longer after the equinox, plants receive a reliable signal that seasons are changing and its time to grow, baby. Unlike temperature, which can fluctuate unpredictably (definitely in the Central Plains and Midwest of the U.S.), day length increases consistently, in a pattern annually.

So… are plants asleep in the winter?

Kind… of?

Many plants are in a state called plant dormancy.

During dormancy:

• growth is suppressed

• buds remain closed

• seeds are inactive

• metabolism slows down

Most plants need two signals to “wake up”:

1. a prolonged period of cold (a chilling requirement)

2. increasing daylight

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Plant hormones: growth is a GO

Just as complicated as our hormones, plants have a coordinated system of chemical signals that says go time.

But first we have to remove something.

1. Abscisic acid (ABA) holds growth back.

• keeps plants dormant during winter

• prevents premature growth during temporary warmups

As daylight increases, ABA levels start to decrease. The “stop” signal is removed.

2. Gibberellins (GA): starting point (and a really fun word to say)

• trigger seed germination

• stimulate stem and shoot elongation

• help break dormancy

3. Auxins: direct growth

• control cell elongation

• direct growth toward light (phototropism)

• support new root and shoot formation

This helps plants know which way is “up” or towards the light.

4. Cytokinins: build new tissue

• promote cell division (remember mitosis?)

• encourage lateral bud growth

• work with auxins to expand leaves

• delay aging in plant tissues (we could sure use this)

5. Ethylene: support transition

• involved in buds breaking

• supports tissue changes and rehydration

• also associated with fruit ripening later in the season

How it all comes together

Now we can see, spring growth is pretty complicated and gardening seems like a miracle.

All these things work together to make it happen:

• increasing daylight activates photoperiodism

• dormancy signals (ABA) decrease

• growth hormones increase (gibberellins, auxins, cytokinins)

• structural and physiological changes activate

All of this happens before we see most growth.

This is just one of the many patterns in nature worth paying attention to.

Have a question?