Ecology, Population Dynamics, and Limiting Factors: Key Concepts for Biology

What does ecology study?

How organisms interact with each other and with their environment.

What is a biotic factor?

A living part of an ecosystem.

What is an abiotic factor?

A nonliving part of an ecosystem.

Give examples of biotic factors.

Fish, plants, bacteria, animals, and other living organisms.

Give examples of abiotic factors.

Water, sunlight, temperature, rocks, and dissolved oxygen.

What is the difference between weather and climate?

Weather is short-term conditions; climate is long-term patterns.

What four processes directly change population size?

Births, deaths, immigration, and emigration.

Which two processes increase population size?

Births and immigration.

Which two processes decrease population size?

Deaths and emigration.

What is immigration?

When organisms move into a population.

What is emigration?

When organisms move out of a population.

What is population density?

The number of organisms living in a certain area.

How do you calculate population density?

Population size ÷ area.

If 300 rabbits live in 6 km², what is their population density?

50 rabbits/km².

What are the three population distribution patterns?

Clumped, uniform, and random.

What does a clumped distribution look like?

Organisms live in groups or clusters.

What does a uniform distribution look like?

Organisms are evenly spaced.

What does a random distribution look like?

Organisms have no predictable spacing pattern.

What is exponential growth?

Rapid population growth when resources are abundant.

What shape is an exponential growth graph?

J-shaped.

What is logistic growth?

Population growth that slows as resources become limited.

What shape is a logistic growth graph?

S-shaped.

Why can't exponential growth continue forever?

Resources such as food, water, space, and shelter are limited.

What is carrying capacity?

The largest population an environment can support over time.

What happens to carrying capacity when available resources increase?

Carrying capacity can increase.

What happens as limiting factors become stronger?

Population growth slows down.

What is a density-dependent limiting factor?

A limiting factor whose effects depend on population density.

Give examples of density-dependent factors.

Disease, competition, and predation.

What is a density-independent limiting factor?

A limiting factor that affects populations regardless of their density.

Give examples of density-independent factors.

Wildfires, floods, hurricanes, and unexpected freezes.

What can happen when a prey population increases?

More food is available, so the predator population may increase.

What can happen when the predator population increases?

More prey are consumed, causing the prey population to decrease.

Complete the relationship: More prey → ______ → fewer prey.

More predators.

Biotic vs. abiotic?

Biotic = living; abiotic = nonliving.

Births/immigration vs. deaths/emigration?

Birth + immigration = increase; death + emigration = decrease.

Exponential vs. logistic?

Exponential = J; logistic = S.

Density-dependent vs. density-independent?

Dependent = population density matters; independent = it doesn't.

What happens when resources increase?

Carrying capacity can increase.