1. Populations & Communities Interactions with the Environment
3.9A observe and describe the physical characteristics of environments and how they support populations and communities within an ecosystem (supporting standard)

2. Individual Interactions with the Environment
Close your eyes and think about what you know about a frog.
We know that frogs live near a pond.
They get their food from the same pond area.
They can move to meet their needs.
Frogs need enough space to live.
They have natural predators.
They need a fairly constant temperature.

3. Populations
A group of individual frogs is a population; a group of the same species that live in the same area.
The size of a population can change.

4. Communities
In an ecosystem there are many different populations living together. These are called communities.
For example, the population of frogs also live in the same ecosystem with a population of birds, snakes, and lizards; their predators.
They also live with insects which is their main food supply.
The different populations all interact with each other and with the environment to survive.

5. What physical features of the environment can affect the population?
Temperature
Rainfall and available water
Food supply (food chain/web)
Increase in predators
Birth and death rate
Geographic range (space)
Rocks, soil, sunlight

6. From the individual to the community
Population
Community

7. Populations or Communities?
All the same species -
Populations or Communities?

8. Populations or Communities?
A variety of species
Populations or Communities?

9. Interactions in the Environment
Abiotic factors
are any
non-living
part of the
environment
Biotic factors
are any living
part of the
environment.
The communities of animals and plants all interact with the physical features in the ecosystem.

10. Temperature
Organisms will survive if all their needs are being met. One of those needs is the range of temperatures where the organism can thrive and reproduce. For example: Too high temperatures will dry up water holes so there would not be enough water. Too low temperatures could freeze some organisms both plants and animals. The change in temperature causes some animals to migrate to different areas. Temperature is a nonliving factor in the environment that affects organisms.

11. Rainfall
Getting the correct rainfall to fill the watering holes is essential to animal life.
In a drought the plants may die and the animals would need to move to find water and food.
Too much rainfall would produce flooding and again destroy plant life and cause animals to move or perish.
The amount of rainfall is a nonliving physical feature of the environment that affects organisms.

12. Food Supply
The food chains/webs in an ecosystem can be affected by both living and nonliving factors in the environment.
Populations may decrease or increase changing the stability of the food web.
Too many predators may make the prey population fewer and fewer affecting several organisms in the food web.
Non-living factors like rainfall, temperature, and amount of sunlight can affect the growth of plants which in turn affects the herbivores.

13. Shelter
The non-living factors in an environment can provide shelter for organisms. For example, organisms can live under rocks or in and under the soil.
Some living factors such as trees, grasses and flowers can also provide shelter for other organisms.
For example, birds nests and bee hives
in trees, and ant tunnels in the soil.

14. Space
Flocks, herds, and basically all groups of organisms require space to live, find food, and reproduce.
Some organisms move to meet their needs to different areas.
Overcrowding and overgrazing of land causes less food to be available to the organisms.
Too many animals drinking from the same waterhole may cause it to go dry or not allow all the animals access to the water.

15. Physical Feature of the Environment: Space!
Is there enough space for these birds to thrive?

16. How does this pond support the living organisms that live there?

17. How does this prairie support the organisms that live there?

18. How does a forest support the living organisms that call it home?
Click on the picture to see an animation of the organisms found in a forest.

19. Check for Understanding
Populations of birds, fish, turtles and frogs live near a pond. Together these different populations make up a - A. habitat B. community C. environment D. species

20. Check for understanding
A population of ants interact with the physical features of their environment by all of these except –
Reproducing
Taking cover from rainfall
Digging tunnels in the soil
Escaping the hot sun

21. Remember…
The physical features of an environment, both biotic and abiotic (living and non-living) support the populations and communities that live there.
The populations and communities interact with each other and the physical features of an environment.