Ecology Flashcards
Abiotic factors:
-nonliving elements of an
ecosystem (eg. temperature, water, light).
Biotic factors:
- living elements of an
ecosystem (eg. plants, animals, etc.).
Species
-: a group that can interbreed and
have viable, fertile offspring.
Population:
- a specific species living in a
specific location.
Habitat:
- the type of place where a specific
organism lives. Includes other organisms
(biotic) and physical aspects (abiotic).
Ecological community:
- all populations in a given area.
Ecosystem:
- all the organisms in an ecological
community (biotic), and the abiotic factors
interacting within it.
Biosphere:
- all ecosystems on Earth, their
interactions with each other and the
lithosphere, geosphere, hydrosphere,
atmosphere.
Density-dependent factors
- depend on population density (eg. disease, resource
competition).
Density-independent factors
- do not depend on population density (eg. climate, weather).
Ecological Niche
- An organism’s niche is the biotic and abiotic
resources it uses. Its realized niche is where it
truly lives and its fundamental niche is the full
range of environmental conditions where it could
survive.
Gause’s Law (competitive exclusion principle):
- Two species cannot occupy the same niche and
maintain population levels: one will outcompete
the other. Resource partitioning allows species
to coexist.
Biological Interactions: competition
- In competition (short-term interaction), 2 species
compete for the same resources. - includes:
1) intraspecific competitions
2) exploitation competition
3) apparent competition
4) interspecific competition
Intraspecific competition
- occurs between members of the same species (eg. two rabbits
competing for carrots).
Exploitation competition
- is indirect and occurs when resources are depleted. (eg.
cheetahs deplete gazelle population, affecting lions).
Apparent competition
- occurs when one predator preys on two species.
Interspecific competition
- occurs when one species directly prevents the establishment of
another species that would compete for a mutual resource. - includes: 1) allelopathy
Allelopathy
- is a type of interspecific competition used by plants where a toxic chemical is secreted to prevent such establishment; common biological phenomenon by which one organism produces biochemicals that influence the growth, survival, development, and reproduction of other organisms.
Symbiosis (living together)
-is a close, long-term interaction between two organisms (symbionts).
- includes: 1) Mutualism, 2) Commensalism, and 3) Parasitism
Mutualism (+/+)
- both organisms benefit (eg.
oxpecker bird eating ticks off rhino).
Commensalism (+/0)
- : one organism benefits
and the other is unaffected. (eg. jackal eating
tiger’s leftovers).
Parasitism (+/-)
-: one organism benefits at the
other’s expense. (eg. tapeworm in human
gastrointestinal tract).
Food chain:
- linear depiction of what eats
what (eg. carrot → rabbit → fox → lion).
Food web:
- expanded food chain depicting
interconnections between food chains.
Trophic level:
- an organism’s position within
a food chain or food web.
Ecological pyramid:
- Graphical representation of the accumulation of
biomass at each trophic level.