Ecology Chapter on Population Dynamics

Population Growth

• Population increases due to immigration, abundant food/space/resources, and fewer predators.
• An invasive species is a non-native species that causes ecological problems.
• Carrying capacity is the maximum number of individuals an environment can support.
• Carrying capacity is reached in phase III of a population growth graph.
• Limiting factors include predation, emigration, competition, natural disasters, and human activity.

Predator-Prey Relationship

• If the predator population increases, the prey population decreases.
• Conversely, if the prey population increases, the predator population increases.

Keystone Species

• A keystone species is a species that the entire ecosystem depends on.
• Examples include the sea otter and Yellowstone gray wolf.

Trophic Cascade

• A trophic cascade occurs when a keystone species is removed.
• This dramatic change affects the entire ecosystem.
• For example, when the gray wolf was removed, the elk population increased, and the plant population decreased significantly.

Carbon Cycle

• Four ways carbon dioxide is released into the atmosphere: respiration, decomposition, volcanic eruptions, and burning of fossil fuels.
• Carbon dioxide is used primarily in photosynthesis.
• High levels of carbon dioxide cause the greenhouse effect, leading to global warming.

Nitrogen Cycle

• Only bacteria convert nitrogen gas into usable nitrogen compounds.
• Nitrogen is essential for creating proteins.
• Free nitrogen in the atmosphere is converted into nitrates and other usable forms by bacteria in soil and water.
• These compounds are then used by plants, and then animals.
• Denitrification converts nitrogen compounds back into nitrogen gas.

Phosphorus Cycle

• Erosion and weathering of rocks and minerals release phosphorus into soil.
• The phosphorus cycle does not involve a gaseous phase.

Explore the nuances of population growth, predator-prey relationships, and the significance of keystone species in this ecology quiz. Dive into concepts like carrying capacity and the effects of trophic cascades on ecosystems. Test your understanding of how various factors influence population dynamics.