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?

<p>Ideal conditions with unlimited resources</p> Signup and view all the answers

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

<p>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.</p> Signup and view all the answers

How do density dependent factors affect population growth?

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

How do density independent factors affect population growth?

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

What are some examples of density dependent factors?

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

What are some examples of density independent factors?

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

Why is it necessary to control introduced species?

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

How can non-native species affect ecosystems and why?

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

What is Thomas Malthus' prediction of population growth?

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

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

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

What can cause a population to shrink?

<p>If the death rate is greater than the birth rate.</p> Signup and view all the answers

What causes populations to grow?

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

What causes a stable population, or zero population growth?

<p>When the birthrate plus immigration equals the death rate plus emigration.</p> Signup and view all the answers

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

<p><em>Random</em>: Purple lupines; <em>Uniform</em>: King penguins; <em>Clumped</em>: Striped catfish.</p> Signup and view all the answers

What is a population?

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

What is age structure graphs?

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

What is the carrying capacity?

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

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

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

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

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

What will reduce competition within a species' population?

<p>Fewer individuals.</p> Signup and view all the answers

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

<p>The death rate may rise.</p> Signup and view all the answers

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

<p>exponential.</p> Signup and view all the answers

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

<p>growing more rapidly.</p> Signup and view all the answers

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

<p>exponentially.</p> 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.
  • 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.

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