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Ecology. What is Ecology. Ecology – the study of the interactions between organisms and the living and nonliving components of their environment. Levels of Organization Biosphere Ecosystem Community Population Organism. Levels of organization within an ecosystem. - PowerPoint PPT Presentation
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Ecology
What is Ecology
• Ecology – the study of the interactions between organisms and the living and nonliving components of their environment.
• Levels of Organization– Biosphere– Ecosystem– Community– Population– Organism
Levels of organization within an ecosystem
• Organism – an individual living thing
• Species – a group of organisms that can mate to produce fertile offspring
• Population – all the members of the same species that live in the same place at the same time– Members of a population generally breed with
one another rather than members of other populations
• Community – a group of various species that live in the same place and interact with each other– Only made up of BIOTIC components
Defining an Ecosystem
• Ecosystem – all of the organisms living in an area together with their physical environment– Ex. An oak forest, a coral reef, a mangrove swamp
• Biosphere – the thin volume of Earth and its atmosphere that supports life.
Biotic and Abiotic
• Biotic factors – the living and once living parts of an ecosystem– Plants and animals– Dead organisms
• Abiotic factors – nonliving parts of an ecosystem– Air– Water– Rocks– Light– Temperature
Taxonomy and Ecology Review1. What is taxonomy? Why bother to classify organisms?2. What is the purpose of a scientific name?3. What two taxa make up an organisms scientific name? How is this
scientific name correctly written?4. Write these scientific names correctly:
– mola mola – homo sapians – tyrannosaurus rex
5. What are the different taxonomic groups? What is the broadest, most inclusive? What is the smallest and most specific?
6. What is ecology?7. What are the levels of organization in ecology from smallest to
largest?8. What is the difference between an ecosystem and a community?9. What are biotic and abiotic factors?
Habitat
• Habitat – the place an organism lives• Habitats have everything (biotic and abiotic)
that the organism needs to survive• Organisms are well suited for their habitats• Very specific biotic and abiotic conditions
Organisms in a Changing Environment
• Tolerance curve – a graph of performance vs. values of an environmental variable
Organisms in a Changing Environment
• Acclimation – some organisms can adjust their tolerance to abiotic factors– Example – Goldfish
• Organisms deal with changes in their environment in one of two ways:1. Conformers – do not regulate their internal
conditions, change as the environment changes2. Regulators – use energy to control some of their
internal conditions to keep them in an optimal range
Organisms in a Changing Environment
• What happens when conditions are unfavorable?– Migration – movement to a more favorable
habitat– Dormancy – a state of reduced activity during a
period of unfavorable conditions
Niche
• Niche – the specific role or way of life of a species within its environment– Often thought of as its “job” or what it does
• Generalist species – have a broad niche; can tolerate a wide range of conditions and use a variety of resources
• Specialist species – have a very narrow niche; have very specific dietary requirements, live in only specific conditions
Self Quiz
• What are the main levels of organization in ecology? How do they differ?
• What are biotic and abiotic ecosystem components?
• What is a habitat? What is a niche? How do they differ?
• What is a tolerance curve?
Producers and Consumers
• Producer – an organism that makes its own food– Also called autotrophs– Example: Plants
• Consumers – organisms that get their energy by eating other organisms– Also called heterotrophs– Example: Rabbits, Cows, Deer, Wolves
What eats what?
• Herbivores – plant eaters• Carnivores – meat eaters• Omnivores – eat both plants and meat• Detritivores/decomposers - get their food by
breaking down dead organisms
Productivity• Production - the synthesis and storage of organic molecules
during the growth and reproduction of photosynthetic organisms• Gross primary productivity (GPP) – the rate at which producers in
an ecosystem capture the energy of sunlight by producing organic compounds– (think photosynthesis)
• Biomass – the organic material that has been produced in an ecosystem. Producers (plants) making organic molecules (like glucose!)
• Net primary productivity (NPP) – the rate at which biomass accumulates in an ecosystem.– NPP = GPP - respiration
Estimated Annual Average NPP in Major Life Zones and Ecosystems
Food Chain
• A linear sequence in which energy is transferred from one organism to the next as each organism eats another organism
Food Chain
Food Web
• Shows many feeding relationships that are possible in an ecosystem.
• Much more complex than a food chain
Food Web
Energy Transfer in an Ecosystem
• Trophic level - each step in the transfer of energy through a food chain or food web in an ecosystem
• Energy is lost each time energy is transferred from one organism to another
Trophic Levels
• Only 10% of the energy is transferred from one trophic level to the next.
• For every 1,000 producers, 1 tertiary consumer
Trophic Levels
Self Quiz
• How does energy transfer through an ecosystem. Explain the number of higher level consumers that can be present?
• What are autotrophs? Heterotrophs?• What is the difference between a food chain
and a food web?• What is productivity?
Ecosystem Recycling
• Biogeochemical cycles – the circulation of substances through living organisms from or to the environment– Water Cycle– Carbon Cycle– Nitrogen Cycle– Phosphorus Cycle
The Water Cycle
The Water Cycle
• The water cycle involves– Evaporation – Condensation – Precipitation– Transpiration – the process by which water
evaporates from the leaves of plants in terrestrial ecosystems
The Carbon Cycle
• The process by which carbon is cycled between the atmosphere, land, water, and organisms.
The Carbon Cycle
• Link between photosynthesis in producers and respiration in producers, consumers, and decomposers
• Movement of carbon from the nonliving environment to living things and back.
The Carbon Cycle
• Plants take in CO2 from the atmosphere through photosynthesis
• Animals eat plants• Animals release CO2 through respiration• Some carbon may be converted into
carbonates, which make up the hard parts of bones and shells– Deposit into carbon sinks– Over time, these become fossil fuels
Nitrogen Cycle
• Nitrogen cycle - process in which nitrogen is cycled between the atmosphere, bacteria, and other organisms.
• Nitrogen makes up 78% of atmosphere– Not in a form most organisms can use
• Nitrogen fixing bacteria - fix atmospheric nitrogen into chemical compounds that organisms can use
Nitrogen Cycle
Nitrogen Cycle
• Nitrogen-fixing bacteria live within nodules on the roots of plants called legumes– beans, peas, and clover
• Plants that do not have nitrogen-fixing bacteria in their roots get nitrogen from the soil.
• Animals get nitrogen by eating plants or other animals.
Nitrogen Cycle
• Decomposers break down wastes and return the nitrogen that these wastes and dead organisms contain to the soil in a process called ammonification.
• Nitrification – the process by which soil bacteria uptake ammonium and form it into nitrites
• Denitrification – occurs when anaerobic bacteria break down nitrates and release nitrogen gas into the atmosphere.
Phosphorus Cycle
• Phosphorus cycle – the movement of phosphorus from the environment to organisms and then back to the environment
• Very slow cycle• No atmospheric component (Carbon and
Nitrogen cycles do)
Phosphorus Cycle
Phosphorus Cycle
• Rocks erode• Phosphate dissolves in water• Plants absorb phosphate through roots• Excreted when organisms decompose
Self Quiz
• Summarize the carbon cycle.• Summarize the nitrogen cycle• Summarize the phosphorus cycle.• How do humans have the potential to impact
each of these cycles?• Which is the only cycle without an
atmospheric component?