UNIT 11: ECOLOGY Union Academy Charter School. Ecology Ecology is the study of interactions among...
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Transcript of UNIT 11: ECOLOGY Union Academy Charter School. Ecology Ecology is the study of interactions among...
UNIT 11: ECOLOGY
Union Academy Charter School
Ecology
Ecology is the study of interactions among organisms and their environment.
Obtaining food
Autotrophs: make their food Producers
Plants, algae, phytoplankton Heterotrophs: eat their food
Decomposer – eats decaying plant and animal matter Fungus, bacteria
Scavenger – eats leftovers Coyote, vulture, hyena
Herbivore – eats plants Carnivore – eats animals Omnivore – eat both plants and animals
Energy transfer – energy pyramid Trophic levels: levels of feeding in a
community
Producers
Tertiary consumers
Secondary consumers
Primary consumers
Quaternary consumers can
exist in some food chains above the
tertiary consumers.
Energy transfer – ecological efficiency
As the levels increase, 90% of energy is lost as heat! 10% rule: only 10% of energy passes to the next
level.
1,000,000 J of sunlight
10,000 J
1,000 J
100 J
10 J
Producers
Tertiary consumers
Secondary consumers
Primary consumers
10%
10%
10%
10%
Solar energy is converted to chemical
energy!
Food chains and food webs
Food chains are a series of steps of energy transfer in an ecosystem (similar to an
energy pyramid). Food webs show all possible food chains in an ecosystem.
Relationships within a community
Symbiotic relationships: two species live closely together. Mutualism: (+,+)
Both species benefit Commensalism: (+,0)
One species benefits, the other is not affected Parasitism: (+,-)
One species benefits the other is harmed Can lead to death
Predator/prey: (+,-) One species benefits and the other is killed
Technically not symbiotic because they are not “living” together.
Predator/prey relationship
Predator/prey populations go up and down in response to one another.
As predators increase, prey decrease.
As prey decrease, predators decrease.
As predators decrease, prey increase.
PreyPredator
Number
Time
Population growth curves Populations grow exponentially when resources are unlimited.
Biotic potential – maximum reproductive capacity under optimal conditions.
Populations grow logistically once a resource becomes limited (limiting factor – ex. water, food, space). Carrying capacity: maximum population size of the species that can
be supported indefinitely. Dynamic equilibrium – populations fluctuate around carrying capacity.
J-shaped S-shaped
The human
population grew like
this following
the introducti
on of sanitation
and medicatio
n!
Population growth curves
A variety of factors can limit the growth of populations. Density-dependent limiting factors –
depends on population size. Competition Predation Disease / parasites Land, food, water etc.
Density-independent limiting factors – does not depend on population size. Natural disasters (earthquake, flood, tornado, forest
fires etc.) Long term change in weather
Human impact – acid rain
Acid rain: air pollutants released by burning coal and other fossil fuels combine with water vapor and fall to earth. Results in rain
10X more acidic than normal. Harms plants and infrastructure and depletes soil of nutrients. NC example: fir trees dying in Carolina mountains.
Human impact – ozone depletion
The ozone layer is a layer of O3 gas that protects us from harmful UV radiation.
Chlorofluorocarbons (CFCs) are depleting the ozone layer. Found in aerosol cans, coolants, solvents, and
plastic foam. Production has stopped but CFCs take a very long
time to break down and are still damaging the ozone layer.
Human impact – global warming
Global warming/the greenhouse effect/climate change: Greenhouse gasses like CO2 and methane (CH4) released into the atmosphere does not allow sunlight to escape, causing the earth to become warmer.
Human impact – biological magnification Some chemicals can not be broken
down by decomposers and end up in the bodies of organisms that can’t excrete them.
Biomagnification: Buildup of chemicals in the tissue of an organism.
Bioaccumulation: Chemicals become more concentrated as they move up the food chain. This effects aquatic ecosystems especially
due to more links in the food chain.
great blue heron
sunfish
mayfly nymph
algae
Human impact – invasive species
Invasive species -species that are not native to the ecosystem Often have no natural predators to maintain population control.
Kudzu into the USA Zebra mussels in the Great Lakes Black rats in Europe and USA Burmese pythons in the Everglades