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