Biology Chapter 5 Population Study Guide

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Questions and Answers

What are the 4 factors that identify how populations grow?

Birthrate, death rate, immigration, and emigration

How do we determine if growth takes place?

By observing how many individuals are added to a population, by immigration or reproduction

How do birthrate, death rate, immigration, and emigration affect growth patterns of a population?

A slow birth rate causes a slow increase in population; a low birthrate with a high death rate causes a drop in population; when the birthrate and immigration equal the death rate and emigration, the population is stable.

What allows exponential growth to take place?

Ideal conditions with unlimited resources Signup and view all the answers

What is the difference between the density dependent and independent limiting factors?

Density dependent factors are strongest when the number of organisms per unit area reaches a certain level; density independent factors affect all populations similarly, regardless of population size and density. Signup and view all the answers

How do density dependent factors affect population growth?

They control the effects of predators on prey and herbivores on plants, which determines population size. Signup and view all the answers

How do density independent factors affect population growth?

They control population size by causing occasional 'crashes' in populations. Signup and view all the answers

What are some examples of density dependent factors?

Competition, predation, herbivory, parasitism, disease, and stress from overcrowding. Signup and view all the answers

What are some examples of density independent factors?

Unusual weather, like hurricanes, droughts, or floods, and natural disasters like wildfires. Signup and view all the answers

Why is it necessary to control introduced species?

Because without control, introduced species would grow quickly and out of control. Signup and view all the answers

How can non-native species affect ecosystems and why?

Non-native species can negatively affect ecosystems because the populations in the ecosystem have not adapted to coexist with the foreign species. Signup and view all the answers

What is Thomas Malthus' prediction of population growth?

He predicted that human populations would be regulated by war, famine, and disease. Signup and view all the answers

What is demography, and why is it important to use?

The scientific study of human populations, which examines their characteristics to explain how they will change over time. Signup and view all the answers

What can cause a population to shrink?

If the death rate is greater than the birth rate. Signup and view all the answers

What causes populations to grow?

When the birthrate is greater than the death rate and immigration exceeds emigration. Signup and view all the answers

What causes a stable population, or zero population growth?

When the birthrate plus immigration equals the death rate plus emigration. Signup and view all the answers

What are the 3 patterns of distribution? Give an example for each one.

Random: Purple lupines; Uniform: King penguins; Clumped: Striped catfish. Signup and view all the answers

What is a population?

A group of organisms of the same species that live together in one area. Signup and view all the answers

What is age structure graphs?

A graph that shows the number of males and females of each age in a population. Signup and view all the answers

What is the carrying capacity?

The maximum number of individuals of a particular species that a particular environment can support. Signup and view all the answers

How do density dependent limiting factors affect a small, scattered population?

They would be least likely affected by density dependent limiting factors. Signup and view all the answers

What kept the human growth rate low before the Industrial Revolution?

Life was harsh, food was hard to find, and predators and diseases were common. Signup and view all the answers

What will reduce competition within a species' population?

Fewer individuals. Signup and view all the answers

If a population grows larger than the carrying capacity of the environment, what may happen?

The death rate may rise. Signup and view all the answers

Human growth has been ______ in the past few hundred years.

exponential. Signup and view all the answers

About 500 years ago, the world's population started __________.

growing more rapidly. Signup and view all the answers

In countries like India, the human population is growing __________.

exponentially. Signup and view all the answers

Study Notes

Population Growth Factors

Four main factors: birthrate, death rate, immigration, and emigration influence population growth.
Population growth occurs when individuals are added through reproduction or immigration.

Growth Patterns

Slow birth rates lead to minimal population increases; high death rates can result in declines.
Stability occurs when birth rates and immigration balance with death rates and emigration.

Exponential and Logistic Growth

Exponential growth thrives under ideal conditions with unlimited resources.
Logistic growth reflects a slowdown after an exponential increase, due to limiting factors.

Limiting Factors

Density dependent factors: effects amplify as population density increases (e.g., competition, predation).
Density independent factors: influence populations regardless of size (e.g., natural disasters).

Population Dynamics

Density dependent factors help regulate predator-prey dynamics and herbivore-plant relationships.
Density independent factors may lead to sudden crashes in population sizes.

Species and Ecosystem Balance

Introduced species can disrupt ecosystems, as local populations may not adapt to new competitors.
Thomas Malthus predicted that population control would be influenced by war, famine, and disease.

Demography Importance

Demography studies human populations, providing insights into their characteristics and changes over time.
Age structure graphs indicate growth potential; a small base suggests less growth potential, while a larger base indicates more.

Population Concepts

Definition of population: a group of organisms of the same species in a specific area.
Birthrate refers to the number of births in a population, while death rate is the number of deaths.

Population Stability and Change

Population stability occurs when birthrate plus immigration equals death rate plus emigration.
A decline occurs if the death rate surpasses the birth rate.

Environmental Carrying Capacity

Carrying capacity: the maximum number of individuals an environment can sustainably support.
Overpopulation beyond carrying capacity can increase death rates.

Human Growth Trends

Recent centuries have seen exponential human population growth.
Growth rates have risen substantially since about 500 years ago due to improved living conditions.

Competition and Population Size

Lowering the number of individuals in a population can reduce intra-species competition.
Small, scattered populations are less affected by density dependent limiting factors.

Historical Growth Influences

Human growth was previously low due to harsh conditions, predators, and disease, with recent advancements leading to rapid increases in population.

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Description

This quiz covers key concepts from Chapter 5 on populations. Learn about the factors that influence population growth such as birthrate, death rate, immigration, and emigration. Test your knowledge and understanding of how these elements affect population dynamics.