Chapter 3: Communities and Biomes

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

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

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

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

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?

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

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.

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.

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.

Chapter 5: Biological Diversity and Conservation

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

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.

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

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

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

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.

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

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.

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

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

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

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

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

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?

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.

Terrestrial Biomes Latitude and Climate

By the way, what causes the seasons?

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

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.