ecology. energy flow in an ecosystem trophic levels ecologists use food chains & food webs to...
Post on 02-Jan-2016
227 Views
Preview:
TRANSCRIPT
Ecology
Energy Flow in an Ecosystem
Energy Flow in an Ecosystem
Remaining Trophic Levels 2. Consumers
Get organic material from other living tissues 3 Types:
Herbivore:• Eats only producers• Ex: Cow, grasshopper, rabbit
Carnivore:• Preys on other heterotrophs• Ex: Wolves, lion
Omnivore*• Eats both plants & animals• Ex: Bears, humans, mockingbirds
Energy Flow in an Ecosystem
Remaining Trophic Levels 3. Decomposers
Fungi (mushrooms), bacteria Breakdown dead organic material and returns inorganic
material back to the soil
Invasive Species
Asian Long Horned Beetle Sighted in Worcester, MA Kills trees
Popular, Willow, Elm Beetle reproduces inside the tree
Larvae tunnel through and eat the tree Tree crumbles
Native to Asia/Japan where there is a natural predator Has no natural predator in the United States
Invasive Species
Asian Long Horned Beetle
Invasive Species
Snakehead Fish Native to Asia Many different species of the Snake Head Fish
Some are huge and very aggressive Get caught in fish nets Attack fisherman
Sold as pets in the United States Pet stores started purchasing smaller versions of this fish
People who could not keep them dumped them into ponds No predator in the United States
Eat everything that lives in a pond (top of the food chain) Deplete entire food source within the pond and then MoVe on
to another pond Shimmy across land primitive lung (in addition to gills)
Invasive Species
Snakehead Fish Evolutionary Advantage
Can breath oxygen Within the air (primitive lung) AND Within the water (gills)
Swim and move across land
Invasive Species
Snakehead Fish
Pollution
Pollution Threatens biodiversity and global stability Changes the composition of air, soil, & water Many types…
Human-made chemicals, not found in nature, are being discovered in food webs Pesticides DDT (dichloro-diphenyl-trichloroethane) Industrial chemicals PCBs (polychlorinated biphenyls)
Biological Magnification
Biomagnification: Increasing concentration of toxic substances in
organisms as trophic levels increase in a food chain/web Carnivores at the higher trophic levels seem to be most
affected Examples of toxic substances accumulating in food
webs: DDT Mercury PCBs
DDT
Highly effective pesticide Used from the 1940s to the 1970s to control
crop-eating and disease-carrying insectsHowever, it caused the eggshells of fish-
eating birds to be fragile and thin death of the developing birds May have played a role in the near extinction of the
bald eagle & peregrine falcon Once these toxic effected were discovered, the use of
DDT was banned in some parts of the world
Mercury
Heavy metal found in the ocean Water Algae Bigger Fish (Tuna, swordfish)
Human
Pregnant women should not eat tuna or swordfish due to the accumulation of the mercury in these fish Link between autism & mercury
PCBs
Manufactured from 1929 until banned in 1979Range of toxicity
Cancer Adverse health effects on the immune, reproductive,
nervous, & endocrine systems
Hundreds of industrial & commercial applications Electrical Heat transfer Hydraulic equipment Plasticizers in paints, plastics, & rubber products
Eutrophication
Another form of water pollution Destroys underwater habitats for fish and other
species
Fertilizers, animal waste, sewage (rich in nitrogen & phosphorus) flow into waterways Resulting in extensive algae growth Algae use up the oxygen supply during their rapid
growth & after their deaths during the decaying process No oxygen in the water = other organisms in the water
suffocate
top related