C

Habitat: An environment that provides an organism with its needs to live, grow and reproduce. One area may contain many habitats Biotic Factors: the living of an habitat Examples: plants and animals Abiotic Factors: the nonliving part of a habitat Examples: water, sunlight, oxygen, temperature, & soil

Levels of Organization 1. Individual: most basic level of organization 2. Population: all of the members of one species in a particular area Species: a group of organisms that are similar and can reproduce Example: all the dear in Solon, all the pigeons on NYC

2. Community: all the different populations that live together in an area. -must live close enough to interact 3. Ecosystem: the community of organisms that live together in a particular area along with the nonliving surroundings

Determining Populations 1.Direct Observation: counting all the members in an area 2. Indirect Observation: counting the “signs” of an organism and estimating the population 1.Example: bird nests, foot prints

3. Sampling: approximation of a population by counting a smaller area 4. Mark and Recapture: Catch a number of individuals, mark them. Return to the area at a later date and catch individuals again. Mathematically compare the number originally marked to the number recaptured.

What counting method would you use to determine the population of: Grizzly bears in a national park? Grasshoppers in a field? Blue herons in a pond area?

Changes in Population Birth/Death Rate: the number of individuals that are born or die over a specific time Birth Rate > Death Rate = Pop. Increases Death Rate > Birth Rate = Pop Decreases Immigration/Emigration: the number of individuals joining or leaving a population

Limiting Factors in Population Size Limiting factors are environmental factors that cause a population to decrease or remain unchanged 1. Food and Water Because organisms require food and water, the amount of resources will determine the populations “ Carrying Capacity”

Carrying capacity: the largest population an area can support with its resources 2. Space: organisms need a certain amount of space to thrive, if this space is not available the population will decrease. Examples: plants, birds (nesting sites)

3. Weather: conditions, such as temperature or rainfall, can limit populations. Cold temperatures can kill both plant and animal offspring Hurricanes can flood and destroy habitats

What are the 3 options an organism has if the environment is not optimal for survival? 1. migrate to better place 2. adapt to fit environment 3. die

Page 17 – Population graph 1. In what year did the rabbit population reach its highest point? 2. What was the size of the population in that year? 3. Not counting the first year of the study, what year was the rabbit population the lowest? In year 4 to 5, what could have caused the population to decrease?

Which is an example of an abiotic factor? A. Water B. Grass C. Trees D. Birds E. I don’t know

What is an example of a biotic factor? A. Oxygen B. Algae C. Sunlight D. Soil E. I don’t know

What might happen if the biotic and abiotic needs are not met by the organism’s habitat? A. More reproduction happens B. Animals move into the area C. Animals move out of the area D. I don’t know

How is the population of a species affected by an increase in immigration? A. Population increases B. Population decreases C. Population stays the same D. I don’t know

What is an example of a factor that limits population size? A. Increase in space B. Decrease in predators C. Decrease in food D. Increase in birth rate

The amount of organisms that can be supported in an area is called the A. Population B. Carrying capacity C. Limiting factor D. Estimate E. I don’t know