Transcript Chap 36 Ecosystems and Conservation Biology

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Every organism requires energy to carry out life
processes such as growing, moving, and
reproducing.
Producers:
Convert light energy from sunlight to chemical
energy
Consumers:
Obtain chemical energy from consuming other
organisms
Decomposers:
Break down wastes and dead organisms
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How is energy passed between these
organisms?
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Flower takes in sunlight
Grasshopper eats flower
Mouse eats grasshopper
Eagle eats mouse
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What is this an example of?
Food chain:
Pathway of food transfer from one trophic level
to another.
Trophic level:
Feeding level
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Always on the bottom of the food chain
Base for all food webs
If we had no producers, would anything live?
No!
Ex.
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Herbivore:
Only eats plants
Carnivore:
Only eats other organisms
Omnivore:
Eats both plants and other consumers
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Primary consumers (1st level consumer)(2nd trophic
level)
Feeds directly on the producers
Secondary consumers (2nd level consumer)(3rd
trophic level)
Consumer that eats primary consumers
Tertiary consumers (3rd level consumer)(4th trophic
level)
Consumer that eats secondary consumers
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What can primary consumers only be?
Herbivores
Omnivores
Carnivores
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At each trophic level, organisms produce waste
and die.
The waste and remains of dead organisms is
called detritus.
Often called scavengers.
Ex.
Earthworms, crayfish, vultures etc.
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Food web:
Pattern of feeding represented by
interconnected and branching food chains.
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Of the light energy that reaches plants what percentage
is used for photosynthesis?
1%
Biomass:
Organic material manufactured by plants
Primary productivity:
The rate of which producers in an ecosystem build
biomass.
Primary productivity determines the maximum
amount of energy available to all higher trophic levels.
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Desert
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Savanna
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Deciduous forest
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Rain forest
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As each consumer feeds, some energy is
transferred from lower trophic levels to higher,
but most energy in the preys organism’s
biomass is lost.
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50% of the energy in the leaf passes as the
caterpillars waste.
The caterpillar uses 35% of the energy from the
leaf for energy for itself.
Only about 15% of the leafs stored energy is
turned into biomass for the caterpillar.
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Energy pyramid:
Shows the energy loss from one trophic level to
another.
An average of 10% of energy is converted to
biomass in the next trophic level.
90% is lost as heat.
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General steps
1. Producers incorporate chemicals from the
nonliving environment into organic
compounds.
2. Consumers feed on producers, either using
them as energy or releasing them as waste.
3. Organisms die and decomposers break them
down and return to soil.
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Pyramid of numbers:
Shows the number of individual organisms in
each trophic level.
Organized like energy pyramids.
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1. Volcanoes, organisms, and cellular
respiration produces carbon dioxide.
2. Plants uses the carbon dioxide and produce
oxygen.
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1. Bacteria convert nitrogen gas to ammonia
through a process called nitrogen fixation.
2. Other bacteria take the ammonia and
produce ammonium though a process called
nitrification.
3. Plants absorb the ammonium and can be
consumed by other organisms.
Organisms die and cycle repeats.
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Plants transpire, and water evaporates from
bodies of water.
Condensation releases by precipitation back to
the Earth.
Run off and groundwater go into bodies of
water.
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Human activities can affect chemical cycling by
moving nutrients from one place to another.
Humans eat vegetables from different parts of
the country.
Human waste might be carried to the ocean in
sewage.
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What is happening to trees and forests?
Deforestation:
Clearing of forests for agriculture.
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Burning of wood and fossil fuels is one source
of carbon dioxide.
As nations industrialize and use wood, carbon
levels increase.
What organisms use carbon dioxide to make
oxygen?
Plants
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All the carbon dioxide builds up in the Earth’s
atmosphere, trapping heat.
Greenhouse effect:
Natural process that stops all sun’s heat from
escaping rapidly back to space.
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This is leading to global warming.
Global warming:
Rise in Earth’s average temperature.
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Who here eats fish?
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Why do some people not eat fish anymore?
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High amounts of mercury.
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If a small fish has mercury in its system and
gets eaten by a bigger fish… the bigger fish
now has a higher amount of mercury in its
system.
The amount of mercury increases as the small
fish gets consumed and moves up a food chain.
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Pollution in the atmosphere affects a gas called
ozone (O3).
Ozone layer absorbs ultraviolet radiation, and
shields organisms.
Ozone layer is thinning because of
chlorofluorocarbons.
Aerosol cans, refrigerator units.
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Which biome has the most biodiversity?
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Tropical Rainforest!
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What is happening to our tropical rainforests?
Deforestation
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11% of the 9,040 bird species are endangered.
680 plant species of the 20,000 plant species in
the US are endangered.
Biologist estimate that 20% of the freshwater
fish in the world have either become extinct or
threatened.
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The human population is increasing so we
need more land for agriculture, roads etc.
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Introduced species: Non-native species
House sparrows, starlings came over from
Europe.
Compete with native birds for nesting spots.
Share resources.
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Overexploitation:
Practice of harvesting or hunting to a degree
that the number of remaining individuals may
not be able to sustain the population.
Ex. Rhino-Use horns for trade and medicine.
Scallop- Overfished for food.
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How to we maintain biodiversity and
ecosystems?
Balance demands for resources
Establish areas than humans can not interfere
with. (buffer zones)
Develop natural resources.