In one area of the Arctic the number of deer has been counted every five years since 1940. The graph shows the number of deer. Suggest a reason why the deer population changed between 1975 and 1990.

In this activity, graphical representations of white-tailed deer population are studied within a given year by looking at seasonal fluctuations in populations and the factors that influence those changes. Students will illustrate how deer populations change over the course of a year.

Begin the activity by asking students: What is a wildlife population? It is the number of individuals of a given species (in this case deer) found in an area. What might cause deer populations to increase or decrease in a given area? What kinds of things might cause seasonal fluctuations in deer populations? Explain to students that deer, and most wildlife, populations show a pattern of increasing with births during the spring and declining throughout the remainder of the year until they are at a low in late winter.

Have students work individually and prepare a graph representing the seasonal deer population cycle for two years. Along the Y axis represent the population level (high, medium, or low). Along the X axis label the four seasons (spring, summer, fall, winter).

Have students discuss the results of their graphs. Discussion questions: Why did they place the population levels where they did for each particular season? What factors influenced the seasonal deer population? What do deer need to survive? What are some of the limiting factors that affect their survival? Are deer populations static or do they tend to fluctuate? Are deer populations ever really in balance with their habitat? Does hunting play a role in keeping deer populations from exceeding what the habitat can support?

b. They eat other organisms to gain energy

Explanation: nutrition is one of the main characteristics of living organisms.animals need the energy from food as fuel to carry out their daily metabolic activities .

Animals depend on already made food as they cannot manufacture their own food.

Most animals feed on plants, they are called herbivores.most animals feed on other animals,they are called carnivores.most animals feed on both plant and animals,they are called omnivores.

Most animals feed on plankton on water,they are called filter feeders.most animals feed on liquid,they are called fluid feeders.

Animals mostly take solid food into their system ,they digest the food,absorb it and egest the waste.