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Define The following Levels:
Biosphere- Combined portion of the planet in which all of life exists includig land, water, and air
Biome- group of ecosystems that have the same climate and similar dominant communities
Ecosystem- a collection of all the organisms that live in a particular place combined with there physical environment
Community- an assemlafe of different populations that live together in a defined area
Population- a froup of individuals that belong to the same species and live in the same area
Species- a group of organisms so similar to one another that they can breed and prduce fertile offspring
Describe the basic approches to ecological research
- Observing- simple or complex
- Experimenting- set up arteficial environments in a lab to test hypotheses
- Model building- a way to study/interpret/explain very complex phenomena and are tested with real life data.
what percent of all the sun's energy is actually used by plants?
Of the energy that a plant gets, how much is stored in the plant?
Describe the different levels of consumers
- Primary consumers- eat plants
- Secondary- feed on primary
- Tertiary - feed on secondary
What is biomass?
The total mass of all organisms in a trophic level
Describe the three Ecological pyramids
Energy Pyramid- Shows the relative amount of energy available at each trophic level. At each new level there is 10% of the energy of the last level
Biomass Pyramid- Represents the amount of loving organic matter at each trophic level
Pyramid of numbers- Shows the relative number of individual organisms at each trophic level.
Why do all organisms require nitrogen?
- to build protiens and genetic material.
- free nitrogen makes up 78% of our air!
Define Nitrogen fixation
Bacteria that live on the roots of some plants capture nitrogen gas and fix (glue) the nitrogen into chemical compounds
plant and animal remains and other dead matter are collectively called______
what does a food web link together?
all the food chains in an ecosystem
Why is carbon especially important to living systems?
It's the key ingredient in all living organisms
what is dentrification
other soil bacteria convert nitrates into nitrogen gas.
what is the main resevoir of nitrogen in the biosphere?
when is a substance called a limiting nutrient?
when it is scarce or cycles very slowly
what is symbiosis?
any relation in which 2 species live closely together
describe the following relationships:
- Mutualism- both species benefit
- commensalism- one benefits, the other is not harmed
- Parasitism- one lives on the other and harms it
what is ecological succession?
series of predictable changes that occurs in a community over time
what is primary succession?
succession that occurs on surfaces where no soil exists(volcanic islands)
The mechanism of population control in which a population is regulated by predation is called a ____
Give exaples of desity-independent limiting factors.
weather, natural disaster, seasonal cycles, certain human activities
what is biodiversity?
the sum total of the genetically based variety of all organisms in the biosphere (variety)
Define Ecosystem diversity
the variety of habitats, communities, and ecological prcesses in the living world
define species diversity
the number of different species in the biosphere
define genetic diversity
total of all the different forms of genetic ingormation carried by all organisms living on Earth today
Why is biodiversity one of Earth's greatest natural resources?
species of many kinds have provided us with foods, industrial producs, and medicines
the process of splitting a habitat into small pieces is called ____
what is biological magnification?
the concentration of a harmful substance increasing in organisms at higher trophic levels in a food chain or web
why do invasice species roproduce rapidly and increase their populations?
their new habitat lacks parasites and predators that control ther population "back home"
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