ECOLOGY & ECOSYSTEMS Flashcards
whats ecology
Scientific study of the interactions among
organisms and the relationship between
organisms and the environment
whats a species
a group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding
whats a population
A group of organisms of one species that
interbreed and live in the same place at the same time
whats a community
two or more different species occupying the same geographical area and in a particular time (interacting)
types of ecological interactions
- symbiosis (commensalism, mutualism, parasitism)
- competition
- herbivory
- predation
whats a symbiosis
Close relationship between species and long-lasting
- At least one of the organisms derives some sort of benefit from the interaction
whats a commensalism interaction
Associations that benefit one species and leave the
other unaffected
* The commensal (species that benefits from the
association) may obtain nutrients, shelter, support, or
locomotion from the host species, which is substantially unaffected
e.g. remoras hitching rides on sharks to access food scraps
whats a mutualistic interaction
both species benefit
* Each species provides something that the other needs
e.g. coral reef (gain nutrients) + zooxanthellae (safe place to live)
whats a parasitic interaction
Live & feed in or on other organisms (hosts) derives
nourishment
– Usually do not kill host But do harm it and may lead to its death
e.g. ticks feeding on mammals, Parasitic tongue-eating lice that lives in the gills and mouths of fish and drinks blood
what are vectors in a parasitic relationship
organisms that carry a parasite but are not affected by it
Factors affecting spread of parasites
- Abundance of hosts
- Accessibility of hosts - Ability of parasites to locate viable hosts can depend on species diversity
- Transmission rate of parasites
- Length of life of an infected host
whats a competition interaction and its 2 types
Interactions among organisms who compete for
limited, shared resources
- Intraspecific competition = Members of the same species pursue shared resources
- Interspecific competition = Organisms from different species also compete for shared resources
whats the Competitive exclusion principle in competitive interaction
- Two species that directly compete for essential
resources cannot coexist (same location) - One species will eventually displace the other
how do competitors coexist in competition interactions
- Adapt over time to use slightly different
resources or use shared resources in different
ways (resource partitioning) - Niches differentiation - they divide up the fundamental niche
whats an ecological niche
includes all of its interactions with the biotic and abiotic factors of its environment
- describes how an organism or population responds to the distribution of environmental parameters, resources and competitors
- relates to the role and position a species has in its
environment; how it meets its needs for food and
shelter, how it survives, and how it reproduces
2 kinds of niches
- Realized niche - range of conditions over which a
species actually occurs - Fundamental niche- the complete range of environmental conditions (temperature, food,
water) over which the species might possibly exist
2 types of competition
Exploitation competition
Interference competition
what is Exploitation competition
Competition for a shared resource
- consumption of a limiting resource by one species
makes that resource unavailable for consumption
by another
- an play an important role in limiting population sizes
what is Interference competition
Aggressive actions designed to drive off a competitor
e.g. Scavengers such as hyenas, jackals, and vultures
fighting over the remains of an animal
what is herbivory
consume plant material - use several different feeding strategies
* Fructivores: feed on fruits
* Gramnivores: feed on seeds
* Grazers: Feed directly on the leaves and young
stems of plants - Many grazers keep specialized
microbes in their guts that can breakdown cellulose (mutualism)
what is predation
Predator capture, kill, and consume other animals
(prey)
– Several feeding strategies e.g. bottlenose dolphins create mud clouds with their tails to trap fish – cause fish to jump up into their mouths
- can drive population dynamics - Predator-prey population cycles
how does predation lead to evolutionary ramifications
Natural selection has produced adaptations among
prey organisms that allow them a better chance of
escaping their predators
* Speed
* Sharp spines,
* Poison
* Camouflage
- Individuals that are more adept/better at capturing prey may live longer/reproduce, etc
why is predation typically beneficial for a
population
- Predators typically remove young, old, and sick - take out the weakest links - produce stronger pops
- controls overall population - decreasing the frequency of disease
what is coevolution
- Predator and prey and parasites and hosts
may evolve in response to one another - species influence each other’s evolution due to
each exerting selective pressure on other
