1. Chapter 3: Communities and Biomes

2. Community
A group of interacting populations that live in the same place at the same time.

3. Limiting Factors
Anything that limits the number of organisms in a given area.
Can be biotic or abiotic
Sunlight
Atmospheric gases (Carbon Dioxide, oxygen, nitrogen, etc.)
Temperature
Water
Availability of food
Many more

4. How do limiting factors influence communities?
Drought
Plants need water
Herbivores need plants
Carnivores need herbivores
Other carnivores need carnivores and herbivores
Decomposers need all of the above
These factors may influence an individual, a population, and all the way up to a community

5. Ranges of Tolerance
Tolerance=an organism’s ability to withstand changes in environmental conditions.

6. Succession
Orderly, natural changes and species replacements that take place in the communities of an ecosystem.
Occurs in stages and is gradual.
First, some species move in.
These species change conditions so that they are suitable for other species.
This in turn brings further species in.
What will The Cities look like after humans?

7. Primary Succession
The colonization of barren land by communities of organisms
Example: After a Volcano eruption, plants begin to grow on the barren land

8. Pioneer species 1st to move in during Primary Succession
Example: Lichens (bacteria and fungus)
As these pioneer species die, they decompose and build a layer of soil
From this layer of soil, plants can grow. These also contribute to soil.
Seeds blown in the wind grow, and bring in the heterotrophs that eat them.

9. Secondary Succession
Series of changes that takes place after an existing community is severely disrupted.
Fire, hurricane, humans
Soil already exists, and other organisms can move in more quickly.
If Primary succession is an empty house for sale, secondary succession would be a furnished house that is move-in ready.
See “An example of secondary succession” on pg. 69 for a real-life example.

10. Climax community
A stable, mature community that undergoes little change in species.
After some time of primary succession, the ecosystem stabilizes and change stops happening as much.
The area has become a climax community.
May last hundreds of years.
Change still happens, just not as drastic.

11. Chapter 5: Biological Diversity and Conservation

12. Biological diversity Biodiversity=variety of species in an area
Most biodiversity is found in warm climates (Tropical rain forest, coral reefs)

13. Importance of biodiversity
Life is interdependent
Organisms rely on one another for food.
All life relies on decomposers to return nutrients to the soil for plants.
Without plants, no oxygen.
Etc.
Biodiversity brings stability
We also rely on biodiversity for food, medications, etc.

14. Loss of biodiversity
Extinction= death of the last of a member of a species
The species is then lost forever
Endangered species= occurs when numbers of a species drop so low that extinction is possible
Threatened species= when a species’ numbers drop low enough that it is in danger of becoming endangered

15. Keystone species (Not in your book)
An organism that has a disproportionately large impact on its ecosystem

16. Beaver as a keystone species
Direct benefits:
Decrease flooding
Recharge supplies of drinking water
Dams filter pollutants out of drinking water
Protect against droughts
Decrease erosion
Other benefits
Produce food for other animals
Support biodiversity, including 43% of N. America’s endangered species
Create aquatic and terrestrial habitats
Maintain stream and river flow

18. Threats to biodiversity
Habitat loss-using habitats as farmland and clear-cutting forests
Mainly due to humans
Habitat fragmentation- separation of ecosystems by roads, communities, etc..
Habitat degradation- damage to habitat by pollution
Climate Change-causing polar ice caps to melt, killing off coral reefs, etc.

19. Invasive species (aka exotic species)
Mainly due to humans
Introduce a species to a new area, and it has a negative impact.
No natural predators in the area, so are able to reproduce rapidly.
Examples:
Zebra mussels
Asian carp

21. Conservation biology
The study and implementation of methods to protect biodiversity.
Includes:
Legal protections: U.S. Endangered Species Act (1973)
Habitat preservation and protection (i.e. National Parks)
Habitat corridors- protected strips of land where organisms migrate
Sustainable use-using resources in a way that maintains ecosystems
Reintroduction programs-Reintroducing species to areas where they once lived
Captivity-Zoos, house plants ,etc. keep them alive, even if struggling in the wild.

22. Biomes
Large group of ecosystems that share the same type of climax community.
Not necessarily identical, but very similar.
2 Types:
Aquatic and Terrestrial
These are then broken down into smaller biomes

23. Aquatic Biomes Most of the Earth (Earth > 75% water)
Broken into 2 Biomes
Marine and Freshwater

24. Marine Biomes These are the oceans and other saltwater bodies
Oceans contain a huge amount of the Earth’s biomass
Ecologists often separate the bodies into zones based on amount of light that gets to a certain depth

25. Photic and Aphotic Zones
Photic Zone=Shallow water that light penetrates
Aphotic Zone=Deep water that no light passes through.

26. Estuaries
Coastal body of water where fresh water and salt water mix

27. Freshwater Biomes Lakes. Ponds, rivers, etc Limiting factors:
Temperature of water (warmer near surface, colder near bottom)
Amount of light (more near surface, less below)
Where would we find the greatest biodiversity?

28. Other Aquatic Biomes Wetlands-where water meets land
Swamps-have trees
Marshes-Do not have trees
Bogs-water comes from rain, but does not flow.

29. Terrestrial Biomes
Latitude and Climate

30. By the way, what causes the seasons?

31. Biome Characteristics
Main 2 that we look at are Temperature and Rainfall

32. Jigsaw with Foldables
Using your own notebook paper, create a foldable following the directions on p. 70
On “Questions” page, write the following:
Short description of the biome (where it is, what it is like, etc.)
What are some unique characteristics of the biome?
What temperatures and rainfall levels do we find in this biome?
What types of organisms are common and uncommon in this biome?
What are some other facts about this biome? (i.e. other common names, where it may be located, anything they are known for, etc.)
As you and your partner(s) explore your biome, answer these questions in the appropriate area in your foldable.
You will then split into larger groups and share your information, while getting the information about the other biomes from other people.