Environmental Science Ch. 4 Study Guide

Define Ecology:

The study of how organisms interact with each other and with their environment.

List the levels or organization from smallest to longest

Individuals →Populations→Communities→Ecosystems→Biosphere

What is the difference between a population and a community?

A population refers to a group of individuals of the same species living in a specific area, while a community encompasses all the different populations of various species interacting in that area.

What is a biotic factor? Give an example.

Parts of an ecosystem that are living or used to be living. A dead tree.

What is an abiotic factor? Give an example.

Parts of a ecosystem have never been living. Temperature.

What do habitats need for an organism to survive?

Resources

What is a resource? Give an example.

Anything an organism needs to live. Nutrition.

A group of geese are in a pond together. What level of organization could be used to describe the geese?

Population

A group of geese are in a pond with a group of fish. The fish, the geese, and the pond can be described as what level of organization?

Community

A steady or increasing population indicates what about the population?

The population a healthy one.

How can population size be determined?

By using sampling techniques. Ecologists will count the number of this species in a sample area, then uses that info to estimate the number of individuals in the larger overall area.

What is one pro and one con of a high population density?

It can make it easier for organisms to group together and find mates, but it can cause competition for resources.

What are the three population distributions? Draw a sketch of each.

Random, Uniform, and Clumped

How are age structure diagrams read?

By analyzing the horizontal bars that stack age groups vertically, with males on the left, females on the right, and the overall shape revealing current population trends and future growth.

What is the ideal sex ratio?

50:50

Define natality and mortality.

The number of births or deaths per 1000 individuals over a given time.

Explain the three survivorship curves. Draw a sketch of each.

Type 1 curve is where organisms have a higher mortality at older ages. Type 2 curve indicates a population with equal mortality at all ages. Type 3 curve is when death is less likely at an older age than at a very young age.

Define immigration and emigration.

Arrival of individuals from outside a given area. Departure of individuals from a given area.

What are limiting factors?

Characteristics of the environment that limit population growth.

What is carrying capacity?

Largest population size a given environment can sustainably support.

Give an example of a density dependent and density independent factor.

Density dependent - increases competition for resources such as food and water. Density independent - Floods, fires, landslides — it doesn’t matter if the original population was dense or not, the result is the same: dramatic and sudden reduction in population size.

What two things can impact biotic potential?

Gestation Time & Generation Time