Biodiversity, Succession and Resources Ecology Day 4

BIODIVERSITY Degree to which species VARY within an ecosystem Which of these has more biodiversity?

WHY IS BIODIVERSITY SO IMPORTANT? The Back-up plan: “Backup” orgs if one species dies due to disease, there is one to fill the niche Maintains stable ecosystem: If lots of orgs, every niche can be filled! Therefore, stable ecosystem! Benefits Humans!: Ensures a variety of genetic material Vast rainforests may hold cures, medicines and other useful resources!

HOW DO HUMANS REDUCE BIODIVERSITY? 1.D EFORESTATION: Destruction of forests IMPACT: Forces many orgs to find new homes If cannot adapt, will become extinct 2.O VER HUNTING: When bounties offered for a certain species, it can become over hunted EX: LION IMPACT: With such a drastic drop, will affect pop’ns of other animals EX: DEER POP’N ROSE B/C NO LIONS; DEER OVERGRAZED AND STARVED THEMSELVES

HOW DO HUMANS REDUCE BIODIVERSITY? 3.Clearing land for farming and space: Replacing a diverse ecosystem with one or two crops Replacing a diverse ecosystem with one or two crops  IMPACT: Taking away resources for ourselves and other speciesIMPACT: Taking away resources for ourselves and other species 4.DIRECT HARVESTING: Taking species out of natural habitat for our benefit (wanting unusual pets or plants)Taking species out of natural habitat for our benefit (wanting unusual pets or plants) IMPACT: We are reducing the # of those species in their natural habitatIMPACT: We are reducing the # of those species in their natural habitat

HOW DO HUMANS REDUCE BIODIVERSITY? 5.IMPORTED SPECIES : When a species is imported and released into a new environmentWhen a species is imported and released into a new environment IMPACT: New species may adapt well and drive out existing speciesIMPACT: New species may adapt well and drive out existing species EX: Rabbits in AustraliaEX: Rabbits in Australia IMPACT: New species often become pests because they have NO NATURAL PREDATORSIMPACT: New species often become pests because they have NO NATURAL PREDATORS EX: Zebra mussels in NY waterwaysEX: Zebra mussels in NY waterways

What is Ecological Succession? A series of changes by which one habitat naturally changes into another PROCESS: Starts with simple habitat w/ little diversity CLIMAX COMMUNITY: A stable diverse habitat (ex. Forest) Will be reached if climate remains stable over a number of years

When does Succession occur? 1.When environment becomes suitable for another community: Grasses grow in shallow soil, but add nutrients as they live and dieGrasses grow in shallow soil, but add nutrients as they live and die Soil then becomes suitable for shrubsSoil then becomes suitable for shrubs Shrubs shade out the grasses and take overShrubs shade out the grasses and take over Over time, shrubs will be shaded out by treesOver time, shrubs will be shaded out by trees 2.When natural disasters occur that alter stable ecosystems Fires, overgrazing, etc…….Fires, overgrazing, etc……. Altered ecosystems will need many successions to recoverAltered ecosystems will need many successions to recover

Stage 1: Bare Bedrock Bare Bedrock

Stage 2: Lichens grow Bare Bedrock With Lichens

Stage 3: Mosses grow Bare Bedrock With Lichens Bedrock With Mosses

Stage 4: Grasses grow Bare Bedrock With Lichens Bedrock With Mosses Grasses

Stage 5: Shrubs and small trees Bare Bedrock With Lichens Bedrock With Mosses Grasses Trees And Shrubs

Stage 6: Climax Forest (100 – 200 years of without disturbance) Bare Bedrock With Lichens Bedrock With Mosses Grasses Trees And Shrubs Climax Forest

Succession can also happen in a lake! Lake Habitat Erosion causes buildup of Organic debris in lake Lake fills in becoming shallower and eventually becomes a swamp Filling in continues an eventually a climax forest results

What resources can we use over and over again? RENEWABLE RESOURCESRENEWABLE RESOURCES Can be replaced naturallyCan be replaced naturally Still need to be used carefullyStill need to be used carefully EX: Fish are renewable but over harvesting and damaging env. can inhibit renewalEX: Fish are renewable but over harvesting and damaging env. can inhibit renewal Can you name some renewable resources?Can you name some renewable resources? Water, food, solar energyWater, food, solar energy

What resources do we use that cannot be replaced? NONRENEWABLE RESOURCESNONRENEWABLE RESOURCES Decisions we make today affect what our future will haveDecisions we make today affect what our future will have Most things we use are being depleted due to industrialization and technologyMost things we use are being depleted due to industrialization and technology Can you list some nonrenewable resources?Can you list some nonrenewable resources? Fossil fuels (oil + natural gas), mineralsFossil fuels (oil + natural gas), minerals PRESERVATION = The 3 R’sPRESERVATION = The 3 R’sREDUCEREUSERECYCLE