Crash Course Botany

Ill let you in on a secret: Plants have besties and frenemies.

They form exclusive cliques no,you cant sit with them.

And dont even get me started on their love lives.

Love triangles?

No,please, try love octagons.

While its easy to think of plants as existing in individual bubbles, nothing could be further from the truth.

In reality, theyre constantly interacting with other organisms in their environment.

Plants social lives are as dynamic as those in a supernatural/horror/crime high school drama.

And dishing about plant interactions isnt just the tea; its essential to their conservation.

Inorder to respond effectively to threats like climate change and habitat loss, we need to know how plants fit into the social fabric of their environment.

Hi, Im Alexis!

And this is CrashCourse Botany.

[THEME MUSIC] How we relate to one another is a big part of our everyday lives for better or worse.

In the school cafeteria, you might see a math wiz and a history buff helping eachother with homework, but you also could catch a confrontation between the drummajor and the star of the spring musical.

This sort of thing happens all the time in nature,too close interactions between two different species are known as symbiosis.

And plant ecology, or the study of relationships among plants, organisms, and their environments, is a huge field.

So, lets start zoomed in, with one-on-one interactions.

Like, plants and fungi are often best buds, swapping beneficial nutrients underground through the plants roots.

The fungis filaments, or thread-like structures, are the perfect conduit for trading food with plants and hot goss, probably.

This type of mutually beneficial relationship is called, appropriately, mutualism.

Another classic example of mutualism is between plants and pollinators, like butterflies, birds, and bats.

They get tasty food in exchange for helping plants reproduce.

And there are some lesser-known pollinator pals, too even gerbils.

In South Africa, they pollinate the Massonia flower by carrying pollen from plant to plant on their furry snoots.

Plants can also participate in commensalism, where one species benefits and the other is just meh, neutral.

Take ferns and bromeliadsthe family that includes Spanish moss and pineapple plants.

Many live on the branches of trees, and while they dont actively harm the trees, they dont do them any favors, either.

But not all social arrangements are good for, or neutral to, the plant.

Many interactions are considered parasitism because the benefit to one species comes at a cost to the other.

Mistletoe, for example, is a parasite that grows high up on a trees branches.

But unlike those bromeliads and ferns, which just kinda hang out on their trees, mistletoe sucks water and nutrients from its tree, which can stunt its growth.

Not exactly a Hallmark movie moment.

Even those plant-pollinator interactions can sometimes head into parasitic territory.

Theresan orchid that mimics the shape and scent of female wasps, so male wasps waste valuable energy and sperm trying to mate with it, while the plant reaps the benefits of pollination.

And, there are insects that rob nectar from flowers without transferring any pollen atall.

Talk about some toxic friendships.

Understanding all of these different interactions isnt just useful for a plant teenager trying to survive Botany High.

Its also crucial toconservation, or the protection ofspecies diversity from threats like climate change and habitat destruction.

After all, we cant restore wildflower meadows without their pollinators, and savingrare bromeliads cant happen if there are no trees for them to grow on.

In other words, all plants are connected to other organisms, so conservation has to consider those networks of relationships.

Anyway, now that weve covered the scale of one-on-one interactions, lets zoom out a level to look at groups of the same species living in the same place.

In other words: populations.

Populations change over time they grow or shrink.

They rearrange themselves into different patterns, or distributions.

And often, these changes are influenced by environmental factors.

These shifts and the forces that trigger them make up the field of population ecology.

Andby studying these types of population changes, population ecologists can learn things that go beyond a single species.

Take Mimosa scabrella, a species in the peafamily thats native to Brazil.

It tends to be one of the first species to regrow in areas that have been disturbed by harmful human activity.

Thats because the tree is super adaptable to different soil conditions, even those that have been depleted by things like mining.

And as it begins to regrow, the plant makes the area more hospitable for other species to do the same.

So, the distribution and abundance of this population in a damaged area is a good indicator of how well the area is recovering overall.

But while Mimosa scabrella is a conservation hero on one hand, it presents conservation challenges on the other.

It only grows natively in one place making it an endemic species.

And endemic species are particularly vulnerable to environmental changes or events.

Think about it: for widespread species, a forest fire might wipe out a local population.

But for an endemic species, that wiped-out population might be the entirety of the species.

So, population ecologists monitor, and sometimes alter, populations for conservation purposes.

Like, the Holy GhostIpomopsis is a particularly extreme example.

This homebody is endemic to only a two-milestretch of a canyon in New Mexico.

And ecologists are using two strategies to conserve it.

One is in-situ conservation, which takes place in the plants native habitat, and involves clearing debris that could fuel forest fires, and trimming back other plants that areencroaching on the Ipomopsiss territory.

The other is ex-situ conservation, wherenew populations are started outsidethe species natural habitat.

Botanists are growing lots of Ipomopsis in botanical gardens so the species wont be lost to a disaster.

And once the plants grow strong, the ecologists reintroduce some of them back to their native habitat in an effort to expand the population.

So, we can study individual species through population ecology.

But we can also zoom out one step further to consider how groups of different species interact in a shared space.

This is the focus of community ecology.

To witness community ecology in action, lets head to the Thought Bubble Welcome to Floridas Everglades, one of theworlds largest wetlands.

Its combination of saltand freshwater, varied soil types, and subtropical climate has led to a diverse community of plants and animals.

Ooo!

Look theres lots of sawgrassover here which can thrive even in low-nutrient soils, and provides shelter for nesting alligators.

I respect you from a distance, large lizards!

Then there are the spatterdock plants, which provide cover for frogs and fish and whose seeds are eaten by ducksyum.

Underwater,manatees feed on seagrasses.

And on land, mahoganyand oak trees provide a habitat for other plantsto grow, like bromeliads and ferns.

On top of that, the Everglades are home to the largest mangrove tree population in the western hemisphere, which not only form habitats locally, but also help shield those inland plants, animals, and people from storms.

But in the early 1900s, nobody really knew about this complex community.

Most Floridians thought that the area was a useless swamp, and developers started to drain it sothey could build on the land.

Enter the journalist and activistMarjory Stoneman Douglas.

In her lateryears, Douglas was determined to save the Everglades.

She wrote articles and published a book that was kind of a love letter to the swaying sawgrass we saw before.

Her writing made a huge impact on publicopinion and Floridians began to recognize the value of this ecological community.

And in 1947, the Everglades National Park opened, which formally protected it.

Thanks, Thought Bubble!

So, plants live their lives in the larger context of communities, and they can play huge roles in shaping their environments.

Like, one plant species might help others grow more by making the environment less harsh.

Community ecologists call this dynamic facilitation.

And the Big Sagebrush plant is a pro at it.

In North Americas deserts, water is pretty scarce, which is a challenge for plants with shallow roots.

But when Big sagebrush sends its super-deep roots far into the soil to search for water, it brings that water up to the shallow-rooted plants as well.

On the more dramatic side of things, plants also engage in competition, where they make the environment more difficult for other species to survive.

Most plants compete with each other for light and nutrients a little healthy competition isn't so bad.

But some plants secrete chemicals from their roots into the soil to prevent other species from sprouting nearby and that is a little more cutthroat.

And competition can get really out of hand when invasive species or species from another area come onto the scene and totally disrupt ecological communities.

For example, a major invader in the western U.S. is cheatgrass.

It was introduced to the region accidentally in the 1800s, likely because its seeds got mixed in with other agricultural products.

Now you see, the problem is, it grows back after the winter thaw earlier than native species do, so it sucks up the water supply first.

Those meanies.

It also produces a lot of plant material that can become fodder for fires, and it can re-sprout super fast even after a fire rolls through.

So, it quickly dominates the habitat and pushes out native species.

This has huge effects on the ecologicalcommunity delicate relationships are disturbed, soil is degraded, and essential nutrients areintercepted.

This all makes it harder to restore the area after its been disrupted.

The good news is there are many conservation efforts happening worldwide to protect plant communities from threats like habitat loss and the effects of climate change.

And, at the local level, your countrys forest service likely provides resources on how you can reduce harm from invasive species in your own community.

This might involve things like removing contaminated soil, or even digging up the plants themselves.

Because, yeah, you exist in community with your local plants.

Whether you realize it or not, you went to the same high school.

Well, sort of.

Whether theyre interacting one-on-one, as a population, or in a community, studying the ecological dynamics of plants at all these different scales gives us the knowledge necessary to conserve them.

Because a community isnt the same without each plant that exists within it, just like a high school isnt the same without every athlete, mathlete, rebel, and artist that grace its hallways.

Next time, well be checking out the role of plants in different ecosystems