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