LECTURE 9
natural selection favors:
herbivores
all life requires ENERGY
the ability to do work
fundamental niche
the complete range of environmental conditions (temp, food, water)
life history
the sequence of events related to survival and reproduction that occur from birth through death
biomass
total amount of organic matter on earth or in any ecosystem or area
INTERspecific: competitive exclusion principle:
two species that directly compete for essential resources cannot coexist; one species will eventually displace the other
respiration
use of energy from organic matter by most heterotrophic and autotrophic organisms
two basic feeding strategies: filter feeding
webs or netlike structures used to filter a predators environment (spiderwebs, krill)
vectors
organisms that carry a parasite but are not affected by it
ecosystems
a biological community of interactions organisms and their physical environment
at its simplest, a community will have: at least one species that is: (2)
a decomposer
species:
a group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding
population
a group of organisms of one species that interbreed and live in the same place at the same time
at its simplest, a community will have: at least one species that is: (1):
a producer
symbioses: mutualism
a relationship in which both species benefit
ecological community
a set of interacting species found in the same place and functioning together to maintain life
interference competition
aggressive actions designed to drive off a competitor; scavengers like hyenas, and vultures fighting over the remains of an animal
Which organism in this food chain of a hot spring ecosystem in Yellowstone National Park is the autotroph? • Algae>herbivorous flies> killdeer birds>grey wolves> decomposing bacteria
algae
predation
capture, kill, and consumer other animals
exploitation competition
competition for a shared resource
ecosystems: structures
compromised of living and non-living organisms
ecosystems: processes
cycling of elements; flow of energy
how do competitors coexist
environment is always changing; dominant competitor today may not be the dominant competitor tomorrow
primary succession
establishment and development of an ecosystem where on did not previously exist; lava flow, glacier)
trophic levels: third tropic level
feed directly on herbivores; carnivores!; tertiary consumers
grazers
feed directly on the leaves and young stems of plants
fructivores
feed on fruits
gramnivores
feed on seeds
decomposers
feed on waste and dead organisms of all trophic levels; scavengers, fungi, microorganisms, termites, etc.
competition:
interactions among organisms who compete for limited, shared resources
symbioses
intimate interdependencies between species
food chains
linkage to who feeds on whom
parasites
live and feed in or on other organisms (host); harmful
INTRAspecific competition
members of the same species pursue shared resources
ecosystem energy flow
movement of energy through an ecosystem from external environment through a series of organisms and back to the external environment
second law of thermodynamics
no use of energy is ever 100% efficient; energy is lost as heat
trophic levels: first trophic level
number of feeding levels away from original source of energy; autotrophs; algae, bacteria
symbioses: commensalism
one species benefits, the other is unnafected
coevolution
organisms can involve in combination; can also benefit each other
INTERspecific
organisms from different species also compete for shared resources;
energy enters an ecosystem primarily through:
photosynthesis; energy fixed by organisms
autotrophs conduct:
photosynthesis; make their own organic matter from an energy source and inorganic compounds
at its simplest, a community will have: at least one species that is: (3)
plus a fluid medium (air, water, or both)
trophic levels: second trophic level
primary consumers; herbivores; feed on autotrophs; heterotrophs
realized niche
range of conditions over which a species actually occurs
secondary succession
reestablishment od an ecosystem following disturbance
two basic feeding strategies: hunting:
stalking and prey
