Factors that affect population size

Summary

This video from MooMooMath and Science explains how various factors impact population size in ecosystems. It highlights that resource availability, predator presence, and environmental conditions all influence whether populations grow or shrink. The concept of carrying capacity, or the maximum population an environment can support, is discussed using examples like owls, zebras, and Yellowstone's elk. Both biotic (living) and abiotic (non-living) factors, such as food, predators, and natural disasters, play a role in population changes. The video underscores how ecosystems balance populations and provides real-world illustrations of these principles.

Takeaways

• 🌳 A rainforest can support thousands of trees, while a desert might not support even one due to resource availability.
• 📊 Population size refers to the number of organisms of the same species living in a particular area.
• 🍃 When resources like food, water, and shelter are plentiful, populations can grow; when scarce, they shrink.
• 🦁 Increases in predators or disease can decrease a population's size.
• 🔄 The balance between births and deaths determines whether a population is growing or declining.
• 📉 Carrying capacity is the maximum number of individuals of a species that an environment can support.
• 🦉 Limiting factors, such as available food and shelter, restrict population growth.
• 🌞 Abiotic factors (like sunlight, water, and temperature) and biotic factors (such as predators and food sources) both influence population size.
• 🔥 Natural disasters or changes in the environment can cause populations to grow, decrease, or crash.
• 🐺 The reintroduction of wolves in Yellowstone National Park led to a significant decrease in the elk population due to increased predation.

Q & A

What is a population in the context of an ecosystem?

A population is the number of organisms of the same species that live in a certain area.

How do resources impact population size?

If resources like food, water, and shelter are plentiful, the population may grow. If resources are scarce, the population may shrink.

What is carrying capacity in an ecosystem?

Carrying capacity is the maximum number of individuals of one species that the environment can support.

What are limiting factors, and how do they affect population size?

Limiting factors are living and non-living components that restrict a population's size. They include abiotic factors like sunlight, temperature, and water, and biotic factors like the availability of food and predators.

How do abiotic factors influence population size?

Abiotic factors such as sunlight, temperature, water, and rocks can impact population size by influencing the availability of resources and the conditions needed for survival.

What impact did the removal and reintroduction of wolves have on Yellowstone's elk population?

After wolves were driven out, the elk population grew to around 17,000. When wolves were reintroduced in 1995, the elk population fell below 10,000 by 2003, and further decreased to 5,349 by 2017.

What abiotic factor in Yellowstone negatively affects the elk population?

High fluoride and silica levels in Yellowstone's water affect the elk by wearing down the enamel on their teeth, leading to a shorter lifespan.

How can natural disasters affect populations in an ecosystem?

Natural disasters like fires, floods, and droughts can cause populations to decrease or even crash by destroying resources and habitats.

What is an example of a biotic factor influencing population size?

An example of a biotic factor is how owls rely on the availability of mice, birds, and other rodents for food. A decrease in these prey species can limit the owl population.

How do interactions between biotic factors shape ecosystems?

Biotic factors interact with each other, such as predators preying on other species or herbivores feeding on plants. These interactions help regulate population sizes and influence the balance of the ecosystem.