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Chap 36 Ecosystems and Conservation Biology. 36.1 Feeding Relationships. 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: - PowerPoint PPT Presentation
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36.1 Feeding Relationships
• 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
• What is this an example of?• Food chain:• Pathway of food transfer from one trophic
level to another. • Trophic level:• Feeding level
Producers
• Always on the bottom of the food chain• Base for all food webs• If we had no producers, would anything live?• No!
Ex.
Consumers
• Herbivore:• Only eats plants
• Carnivore:• Only eats other organisms
• Omnivore:• Eats both plants and other consumers
Consumers• 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
Decomposers
• 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.
36.2 Energy Flows • 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.
Ecological Pyramids
• 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.
Caterpillar eats a leaf
• 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.
Energy Pyramid
• 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.
Pyramid of numbers
• Pyramid of numbers:• Shows the number of individual organisms in
each trophic level.• Organized like energy pyramids.
36.3 Chemical Cycles
• 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.
Carbon and Oxygen Cycle
• 1. Volcanoes, organisms, and cellular respiration produces carbon dioxide.
• 2. Plants uses the carbon dioxide and produce oxygen.
Nitrogen Cycle
• 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.
Water Cycle
• 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.
36.4 Human Activities
• 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.
Carbon Cycle Impacts
• 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
• 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.
Other effects of Pollution
• Who here eats fish?
• Why do some people not eat fish anymore?
• High amounts of mercury.
Bio Magnification
• 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.
Ozone Layer
• 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.
Threats to Biodiversity
• 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.
Habitat Destruction
• The human population is increasing so we need more land for agriculture, roads etc.
Introduced Species
• Introduced species: Non-native species• House sparrows, starlings came over from
Europe. • Compete with native birds for nesting spots.• Share resources.
Overexploitation
• 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.