Download ORGANISMS AND THEIR ENVIRONMENT

ORGANISMS AND THEIR
ENVIRONMENT
The Biosphere
= any part of the earth which supports living
things
– Includes land, water, and soil
– Consists of biotic (living) things and abiotic
(non-living) things
• Biotic factors: plants, other animals, fungi,
bacteria, etc.
• Abiotic factors: air temperature, length of day and
night, soil quality, amount of rainfall, etc.
Ecological Levels of Organization
• Individual Organism
– Each organism has a habitat where it lives out its life
• Example: a lawn, a pond, a grove of pine trees
• Size of habitat varies for different species
– Several different species can share a habitat
• Example: a pond contains many different species of fish, plus
bugs, plants, bacteria, etc.
– Each species occupies a niche in the habitat—how it
lives, what it eats, etc.
• No 2 species can occupy the same niche in the same
habitat
• Population = group of organisms, all the same
species, living in a particular area at the same
time
– Example: we can talk about the elk population in
Rocky Mountain National Park
• Community = several interacting populations
living together in an area
– Example: the forest community in RMNP, which
includes elk, deer, bears, many different plants, etc.
• Ecosystem = community and the abiotic factors
– example: the forest community and the climate,
temperature, pollution, wind, etc.
• Biosphere
Symbiosis
= a close, permanent relationship between 2
different species
3 kinds: mutualism, commensalism and parasitism
• Mutualism = symbiotic relationship in which
both species benefit
– Example: lichen, which is a combination of an algae
and a fungus
• fungus is “fed” by food made by the algae, which can do
photosynthesis
• Algae benefits because the fungus is better able to find and
soak up water
– Example: cleaner wrasse lives on other
fish
• Fish gets cleaned by the wrasse
• Wrasse gets food from whatever it
can scavenge
– Example: E. coli which lives in your gut
• E. coli breaks down your food for you
• E. coli gets a lot of nutrients from your
food
• Commensalism = one species benefits, the
other is neither helped nor harmed
– Example: birds that ride on cows’ backs
• Birds get food to eat when the cow walks and stirs up insects
• Cow doesn’t care—it doesn’t get anything back from the bird
at all
• Parasitism = parasite harms, but does not
kill, the host; parasite benefits, host is
harmed
– Example: tapeworm which lives in intestines
of animals
• Tapeworm eats your food and harms you
– Example: brown-headed cowbird is a “nest
parasite”
• Lays eggs in nests of songbirds so the other birds
will raise their young for them