Transcript Ecology - SharpSchool

Ecology
(Interdependence)
Response to organisms &
changes (Interdependence)
• Interdependence of organisms:
– Interdependence is when organisms in a biological
community have evolved to live and interact with other
organisms.
– A biological community is a group of interacting organisms.
– Ecology is the study of the interactions of organisms with
each other and their environment.
– Sunlight is the ultimate energy source for all organisms.
– Energy from the sun is passed from one organism to another.
» Ex: Producers (plants) to herbivores to carnivores to decomposers.
– Abiotic factors, such as air, water, energy, soil, temperature, and minerals are
also needed for survival.
– Biotic factors include all living things on earth (plants, animals, fungi, &
microorganisms)
– Biosphere supports all life, including the biotic and abiotic factors on earth.
2
Organismal Relationships
1. Producer/Autotrophs
• Producers (autotrophs): organisms that can
use energy directly from the sun to produce
simple sugars (glucose) that other organisms
can use for food
a. The sun is the ultimate source for most
life on earth
b. Less than 1% of the suns energy that
reaches the earth is used by living organisms
•
Producers do not have to eat other
organisms to survive
Ex: plants, algae, some protists,
some bacteria
** Remember the equation for
photosynthesis:
6CO2 +6H2O+light  C6H12O6+6O2
2. Consumers/Heterotrophs
• Get energy by eating (consuming) food either plant
or animals and therefore must depend on other
organisms for food
• Get energy through the process of cellular
respiration
C6H12O6+6O2  6CO2+6H2O+ATP
• Consumers that eat producers are considered to be
primary consumers since they are the primary (first)
things to eat in the food chain.
• When you eat the cow you are then a secondary
consumer since you are the second thing that eats.
Ex: some protists, all fungi and animals
3. Decomposers and Detrivores
•
•
•
Both are consumers since they don’t make their
own food
Decomposers break down dead organisms into
matter called detritus.
Detritus- non-living particulate organic matter (as
opposed to dissolved organic material).
–
•
It typically includes the bodies or fragments of dead
organisms, as well as fecal material
Detrivores convert the detritus (organic matter) into
inorganic matter like nitrogen which plants need to
survive
Ex: earthworms, nematodes, most bacteria,
some protists
4. Plant-Herbivore
• Herbivore: an animal that eats producers
Ex: Cows eating grass
• Herbivores usually have special adaptations
to chew and digest their food
Ex: Cows have large molar teeth
designed to chew grass and break down
cellulose; they also have special bacteria
that help them to digest their food; most
have longer digestive systems since
plants take longer to digest
• Plants have adaptations like thorns and
poisons to keep herbivores from eating them
5. Predation (Predator/Prey)
• Predators: capture and feed on members of another
species
• Prey: the organism getting chased and eaten
Ex: A hawk(predator) hunting and eating a
rabbit(prey)
• Predators have adaptations that help them to
capture their prey
Ex: A hawk has keen eyesight, sharp talons, and
a sharp beak
Ex: Mountain lion has fur that allows it to blend
into its environment
• Prey have adaptations to avoid being eaten
Ex: poisonous frogs have bright colors to warn
predators of dangers
– mimicry: looking like a dangerous organism
Ex: King snake (harmless) mimics a coral
snake (dangerous)
– Camouflage: Organisms blending in with their environment
Ex: Leaf bug looking life a leaf
6. Competition
• whenever organisms try to use the same
resource like food, water, light, or space
Ex: Two birds are competing for the
same food source, nesting space, or
water supply one species will be more
successful than the other.
• competitive exclusion: the extinction of one
species due to competition with another
species
7. Symbiotic Relationships: two species live
together (Symbiosis means living together)
– Mutualism
• Both species benefit
– Ex: Insects and bees; the flowers provide insects
with nectar and pollen and the insects provide the
flower with pollination
– Commensalism
• One species benefits and the other
species is neither harmed nor benefited
– Ex: Barnacles on whales; the whale is neither
harmed nor benefited while the barnacles hitches a
ride on the whale, the water moves and the barnacle
traps food (filter feeding)
– Parasitism
• one species benefits and one is harmed and
possibly killed
– Parasite: lives in or on another organism (the host); it gets
its nutrients from the host; the host is not usually killed,
but is weakened
» Ex: Heartworms on your dog
Ecosystem organization
Organism
• An individual living thing
•
Ex: mouse
Population
• Organisms of the same species live in the same place
• Ex: group of mice in a field
Community
• All the different species that live in the same place at the same
time
• Biotic factors: Living things in the environment (plants,
animals, fungi, bacteria, protists)
• Ex: Field of grass, field mice, earthworms, insects, lizards, etc
Ecosystem
• All the living organisms (biotic factors) and their
environment, such as rocks, soil, etc.
• abiotic factors: Non-living parts of the environment
(water, rocks, soil, sunlight)
Biosphere
• All the ecosystems in the world; the portion of earth
where living organisms can survive & interact with
non-living factors
• Ex: Earth
Human Impact & Succession
Human Impact
• Natural Population Growth
– Follows an S-shaped curve
• A new population in an ecosystem will grow slowly
at first and then more quickly, since there will be
unlimited resources.
• When the population levels off, it has reached
carrying capacity
• Carrying capacity: the largest number of organisms
the environment will support.
– As long as the birth/death rate and immigration/emigration
rates are the same the organisms could live at carrying
capacity.
• This rarely happens; therefore, populations are
limited by limiting factors.
• Limiting Factors: Factors that limit the population
growth
• food
• water
• habitat
Unrestricted Population Growth
• When a non-native (invasive) species is
introduced into an ecosystem, it normally
has few or no natural predators and has
plenty of food.
• This causes the J-shaped curve
• Ex: Two dozen rabbits were introduced into
Australia in the 1800’s. They had no natural
predators and unlimited food so they
overpopulated. They multiplied quickly and
now hunters can shoot 1200 rabbits a day
and it would make no difference. They
wiped out the plant population causing the
extinction of 1/8th of the mammal species.
Effects of Technology
• Technology has allowed rapid population
growth causing an increased competition for
other space, food, and water.
• This disrupts how nutrients are recycled.
• After people were hunters and gathers, we
became farmers.
• This caused a need to clear land and for
people to live closer to each other, which
caused large areas of land to be cleared.
– Technology has allowed us to: irrigate, have
chemical fertilizers, and chemical pesticides.
– When it rains the fertilizers run-off into the water
causing an algal bloom.
– When the algae dies off, decomposition depletes
the oxygen from the water causing the aquatic
animals to die.
• Pesticides have caused a problem in nature, as well.
• Some pest are resistant, so stronger pesticides are
needed.
• Some pesticides, like DDT, build up inside tissues.
• This build up is called biological magnification.
• EX: When a big fish eats a small fish it takes in the
DDT. As the big fish eats more small fish it steadily
accumulates. When an eagle eats the bird, it
accumulates in the bird. DDT causes the eggs to
become frail so when mama bird sits on the egg they
crack. This almost caused the extinction of the bald
eagle.
The Use of Natural Resources
• After the industrial revolution people started using
more machines.
• Machines need to be powered using natural
resources, such as oil.
• Non-renewable resources: take millions of years to
form; coal, oil, natural gas.
• Renewable resources: can be renewed quickly, but
they are not available in renewable amounts; trees,
fresh water
• Both renewable and non-renewable resources are in
limited supply, so conservation is necessary
• Burning fossil fuels to power these machines often
results in acid precipitation which damage many
plants and other resources
• Land pollution, or trash, is more common,
and most of these products take a long time
to decompose
• Natural products, like banana peels, cotton
clothing, or paper biodegrade quickly, since
they are easily broken down by
microorganisms. They are returned to the
soil in a matter of days, week, or months.
• man-made products, like rubber, plastics,
chemicals, and metals take hundreds of
years to biodegrade, since they are not
broken down easily by microorganisms
• Glass bottle 1 million years
Monofilament fishing line: 600 years
Plastic beverage bottles: 450 years
Disposable diapers: 450 years
Aluminum can: 80-200 years
Boot sole: 50-80 years
Styrofoam cup: 50 years
Tin can: 50 years
Leather: 50 years
Nylon fabric: 30-40 years
Plastic film canister: 20-30 years
Plastic bag: 10-20 years (???)
Cigarette filter: 1-5 years
Wool sock: 1-5 years
Plywood: 1-3 years
Waxed milk carton: 3 months
Apple core: 2 months
Newspaper: 6 weeks
Orange or banana peel : 2-5 weeks
Paper towel: 2-4 weeks
Effects of Urban Development
• Humans needed places to live, so they took homes from
many organisms
• When large areas of land are used for humans, the
biodiversity of organisms is decreased
– Biodiversity: variety of life in an area
• Fertilizing and chemicals on lawns and garden also cause
problems
– native plants “weeds” are often killed for grass to take their place
– slugs, aphids, and grasshoppers are killed by the pesticides
– chemicals seep into groundwater or local water supplies
• Non-native (exotic) species are often introduced, which
compete with the native species.
– Non-native plants/animals are often bought as pets, & then are
released into the wild because those “pets” often get too large or
families no longer want to care (or do not know how to care) for
them.
– Non-native species have no natural predators. This causes them
to take over the niches of native species
Ecological Succession
• Ecosystems are always changing.
– These changes may result from natural causes, like
weather, volcanoes, or even from human actions, like strip
mining.
• Ecological Succession: A series of predictable
changes in an ecosystem.
Primary Succession
• Primary means first.
• This succession starts where there is no soil
or nutrients (bare of vegetation).
• Occurs after disturbances, such as volcanic
eruptions
• Pioneer species are the first things to grow
in this area ex: lichens
– Lichens can form on bare rock and over time turn
the rock into soil.
• As soil accumulates, smaller animals, such
as worms and grasses, can be found here.
– These small animals give way to shrubs and birds
which give way to trees and larger mammals.
Secondary Succession
• Occurs when something has existed
there before, such as after a forest fire
– Nutrients are already in the soil
– it is known as the second community
• The soil is not removed and usually
seeds are present in the soil.
– The community is not starting from
scratch.
Climax Community
• The final community of organisms
– Hardwoods, such as maples and oaks, are
found here
• Changes little but are still affected by
non-native species
• Secondary succession takes less time
to reach a climax community than
primary succession.
Succession in a pond
• Never reach climax communities
1. Water plants begin to grow
2. sediment falls into the pond and the
plant’s roots anchor the soil
3. Sediment will continue to fall in until
the pond is filled in with soil, which will
eventually lead to grasses and trees