Population Ecology Activities
How Elephants, Wolves and Deer can SAVE your population ecology activities.
Pop quiz: what’s the best way to save an endangered animal?
Your students might immediately refer to hunting and poaching and that is part of the story, but that doesn’t solve the problems.
Take African elephants. In 1989, the world banned the international ivory trade after poachers had cut elephant numbers roughly in half in just ten years. Victory! Except… elephants are still in trouble. Why? Because farms, roads, fences, and towns keep shrinking the land they can roam. In some fenced reserves, protected herds have grown so big they’re munching through trees faster than the land can bounce back. No guns required. The elephants simply ran out of room.
Or take gray wolves. By the mid-1900s, they’d been hunted, trapped, and poisoned out of almost the entire lower 48. Then came legal protection and the famous 1995 return to Yellowstone. Happy ending? Mostly! But how many wolves the land can support still depends on how many elk and deer are around, how much wild space connects their territories, and how the neighbors (hello, ranchers) feel about having a predator next door. In 2026, hunters purposefully tracked and hunted wolves that were essential to their packs if they left Yellowstone.
Here’s the big idea hiding in both stories: carrying capacity, the maximum number of animals an environment can support. Every time humans interact they change the food, water, or shelter in an ecosystem, we change how many animals can survive there, whether anyone ever picks up a rifle or not.
So let’s be honest, “carrying capacity” can make a room full of students glaze over faster than a late Friday afternoon.
Didn’t I mention something about deer?
Your students may never see a wolf or an elephant in nature, but what about deer. White-tailed deer were nearly wiped out in the early 1900s. Today they are common enough to cause car collisions and overbrowse forests. What happened, and what keeps the population from growing forever? Now we start building a real connection.
Three animals, one big idea: carrying capacity. Humans can shrink it, restore it, or crank it way up, often without meaning to. And here’s the fun part. These species don’t just illustrate one lesson. They can follow your students through the entire population ecology unit.
Essential Questions for your Population Ecology Unit.
- What determines how large a population can grow?
- How do other species and the physical environment cause populations to rise and fall?
- How do changes to an ecosystem, including human activities, affect populations and biodiversity?
- How can we use population data to make responsible management decisions?
I like to kick the whole thing off with a hands-on simulation: Oh Deer! Modeling Lab
Download this Resource for free:
Connecting the Lab to the Language
Students get the chance to experience how resource availability changes population size. Not read about it or be told, but actually experience it. With this information they are living out the vocabulary.
- Carrying capacity
- Limiting factors
- Density dependent and Density independent factors
- Logistical growth
- Exponential growth
In the lab teachers have the chance to run the simulation using competition as the main factor, but later they can run it with disease, weather, immigration or emigration.
My full lesson follows up with notes and a worksheet packet.
Applying new vocabulary.
Population growth and carrying capacity. You’ve already built your foundation with the Oh Deer! Modeling Lab. Now ask students to sketch what they think the Yellowstone wolf population did after 1995, then compare their predictions to the real story. Spoiler: it didn’t grow forever.
Density-dependent vs. density-independent factors. Elephants and deer are perfect here. Competition for food in a crowded reserve or an overbrowsed forest? Density-dependent. A severe drought or a brutal winter that hits every herd no matter its size? Density-independent. Students love sorting real-world scenarios, and suddenly the vocabulary sticks.
Community interactions. Wolves and deer make a perfect predator-prey pair. Take wolves out of an ecosystem and deer numbers can climb until the forest pays the price. Bring wolves back, as Yellowstone did, and the ripple moves through the whole food web. It’s a natural bridge from “one population” to “how populations shape each other.”
Human impact and conservation. Now circle back to that pop quiz. Students have the tools to explain why banning hunting wasn’t enough for elephants, why wolves still depend on human tolerance, and why deer became “too successful.” Habitat loss, habitat change, and predator removal all reshape carrying capacity, and students can argue it with evidence instead of guesses.
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What are population ecology activities?
Let’s start with carrying capacity. The carrying capacity of an ecosystem is the amount of biomass that a specific habitat can support. The habitat can be as small as a drop of water or as large as the entire planet. The idea is that there is a finite amount of abiotic and biotic factors available to any given system. The carrying capacity is the number of all species or a specific species in an ecosystem when population growth remains relatively constant. There is a lot of overlap between population ecology and evolution. If you are looking for ideas for your evolution unit, check out my natural selection lab post.
Typically you will see carrying capacity illustrated in a line graph that looks something like this
The carrying capacity is where the population growth seems to stabilize. Indicated by a straight yellow line below.
Use a Carrying Capacity Game
I prefer hands-on learning. If you have a large space, I suggest doing the Oh Deer Game . As a result, students will quickly see that competition for resources impacts how many deer (or other species are in a single population). This is a modeling lab disguised as a game. If you scroll up you can download a copy immediately.
Follow up with a Carrying Capacity Worksheet.
Follow up the game (aka modeing lab) with a quick worksheet where kids can use their new knowledge of carrying capacity. In this free activity, students use their new vocabulary to solve a riddle related to ecology.
Do you need extra background?
What is population growth?
Population growth is the number of new organisms (through sexual and asexual reproduction) and the number of organisms that die during the same period. This gives the net population growth. If it is positive then the group is growing in numbers, but if it is negative the group is decreasing in numbers. The population growth reflects the carrying capacity.
This isn’t always negative, but these population growth curves are monitored closely by environmental scientists and conservation biologists. Therefore, we use population growth curves as one way to monitor and prevent more threatened species.
The general population curve looks like this familiar graph. This is the same graph that we see in the carrying capacity activity and carrying capacity worksheet.
There are typically two phases of population growth. In the first phase, there is exponential growth because it is not limited by the resources. Logistic growth (usually a S-shaped pattern) occurs in phase two because it will stabilize. The population will go up and down slightly as the result of the population reaching the maximum for the resources available.
In this graph, the exponential growth is circled in red and the logistic growth is in yellow.
How does this relate to threatened species, like African elephants?
One of the biggest impacts that humans have on other species is habitat destruction. When species don’t have a place to live their numbers dwindle. Find out what conservation biologists are doing to help endangered and threatened species. Species in an ecosystem work together with each having a specific role so that a single change can impact the entire ecosystem.
Threatened species of African elephants are being impacted by habitat destruction and poaching. Therefore, understanding carrying capacity and population growth help scientists track these species and prevent extinction.
Carrying Capacity is crucial for conservation
It is imperative that we make understanding the critical relationships between space, resources, and population growth a topic that all students understand. Introducing threatened species like the African elephant and other species closer to home (like the work to save the American eagle) is a great way to make ecology meaningful. There are things that we can do to save species and understand that each species has a role in their ecosystem and the balance of nature (which humans are part of).
One of the ways to get kids excited is by presenting materials in a new way. Population growth is not just an animal issue. The idea that the earth has reached its carrying capacity for the human population has been debated for years.
Ecology isn’t just something that should be discussed in the classroom, but is crucial for the health of the planet and every species that lives here. Using interactive population ecology activities like a carrying capacity activity, carrying capacity game, and/or a threatened species like African elephants make it more interesting for students and easier for teachers to teach.
Make sure to check out or other teaching ideas for ecology units.
Human interaction and impact is important.
Nothing is ever as simple as we would like to think it is. Protecting species from overhunting or poaching is a good start, but not the entire solution. Many species have not benefitted from their relationship with humans.
Hunting is only one way humans affect wildlife. Every time we change the land, we change its carrying capacity, and with it, how many animals can survive. It’s a tough concept to teach, but turn it into a game-style lab and students stop memorizing it and start understanding it.
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