Studied by 11 people
trophic structure
Feeding relationships between organisms in a community.
Heterotroph
is an organism that synthesizes its biomass from the consumption of organic tissue
Detritivore
heterotroph that feeds on dead tissue but does not mineralize organic material back to nutrients (scavengers)
Decomposer
Heterotrophs that MINERALIZE dead organic material back into inorganic nutrients (fungi, bacteria)
what happens when energy transfers to next trophic level?
only about 10% of energy is transferred
Bioconcentraion
uptake of contaminants from water
Biomagnification
uptake of contaminants from food
Bioaccumulation
uptake of contaminants from all food
Homeorhesis
A dynamic system that returns to a specific trajectory instead of a specific point
resistance
is the ability of a community to remain unchanged when challenged by disturbances
resilience
is a measure of the rate a community can recover following a disturbance (inverse relationship between resistance and resilience)
specilast
cannot cope with wide range of conditions, but v. little competition
generalist
can cope with wide range of conditions, but lots of competition
is an ecosystem with a lot of generalists more resilient or resistant?
more resilient (organisms can tolerate more change)
Hysterisis
is the dependence of a state of a system on the history of that system
Nikolaas Tinbergen's four questions
mechanism-what stimulus causes behavior?
ontogeny-how does an individuals reaction or response to the stimulus change over lifetime?
adaptive value- what about the behavior increases an individuals fitness
phylogeny-what is the evolutionary history of the behavior?
What is behavior?
is action (stimulus-response) that alters the relationship between an organisms and its environment
innate behavior
inherited or inborn
flexible behavior
condition dependent (response to environmental conditions)
what type of behavior is reflexive behavior
withdraw reflex(innate)
what type of behavior is learned
learned is a flexible behavior (changes in response to learning)
instinctual
inborn/ inherited/ inflexible
rover allele
Favored at high population density More likely to find unused food patches
sitting allele
favored at low population density
sexual dimorphism
the phenotypic differences between males and females of the same species
Sexual selection
differential reproductive success resulting from differential abilities to find a mate
Parental investment
refers to the energy, time and resources devoted to mating, gestating, and caring for offspring. (usually higher parental investment for females)
reproductive success
the number of offspring an individual produces and rears to reproductive age; an individual's genetic contribution to the next generation
do males or females have a high variance in reproductive success?(in most cases)
Males. males have little parental investment so their reproductive success is limited by how many mates they can have instead of how many eggs they can produce
intrasexual selection
interactions between members of the same sex
intersexual selection
Interactions between members of opposite sexes
infanticide
Males kill females young in order to gain mating opportunity
phenology
the study of seasonal timing in life cycle events
female choice sexual selection
Females choose which males to mate with. Features the female prefers will be selected for.
sneaker males (redback spiders)
male sneaks in while other male "dances" bc female might eat male after mating. sneaker fertilizes eggs without female knowing
polygyny
One male, several females.
classic Polyandry
One female, several males. (males tend to clutches)
cooperative polyandry
one female, several males. (all males raise babies together)
Migration
cyclic movement often in response to cyclic environmental change
diel migration
daily migration trade off between predator avoidance and food
Seasonal Migration
moving with each season or in response to labor or climate conditions
piloting
remembering landmarks while navigation migration
compass orientation
ability to identify directions in navigation
true navigation
ability to locate a specific place on Earth's surface
why migrate?
trade off between risk and benefits(energy, predation, not reproduction for resources, habitat, avoid cyclic hazards)
dispersal
is the movement of individuals in a population, typically from the area of birth to a new location (different than migration)
communication
is a social process in which a signal from one individual modifies the behavior of another individual
language of light (fireflies)
uses flash patterns to signal bad taste to praetors and attract correct mates.
some species provide inaccurate info to mislead predators when does this work best
when it is relatively rare
frequency-dependent selection
as the strategy becomes more common fitness decreases
altruism
behavior with a direct fitness cost to the individual carrying out the behavior and a direct fitness benefit to the recipient
kin selection
Pass down your genetic info by producing offspring or by helping your relatives produce more offspring
Hamilton's rule
when C < r x B (then altruism is favored)C = cost to the altruistic party r = genetic relatedness B = fitness benefit to recipient of altruism
direct fitness
derived from an individual's own offspring
indirect fitness
derived from helping relatives have more offspring than they could otherwise
inclusive fitness
direct fitness + indirect fitness
Coeffcient of relatedness
rBC = (sum of)(rBA x rAC)
r between half siblings
1/4
r between full siblings
1/2
r of diploid sisters
0.75
r of diploid mother to daughter
0.5
reciprocal altruism
an exchange of fitness benefits that are separated in time
altruistic behavior among unrelated species (why does it help)
increases likelihood of receiving help in the future from non kin
Coevolution
Process by which two species evolve in response to changes in each other
competition
a -/- interaction that occurs when individuals use the same limiting resources
intraspecific competition
occurs among members of the same species. Intraspecific competition is a major cause of density dependent population growth
interspecific competition
competition occurs between members of different species
consumptive competition
occurs when two species consume the same resources
preemptive competition
exists when one species makes space unavailable to another species
overgrowth competition
happens when one species grows above another
Chemical Competition
takes place when one species produces toxins that negatively affect another species
territorial competition
arises when a mobile species protects its feeding or breeding territory against other species
encounter competition
occurs where two species interfere directly for access to specific resources.
niche
The range of resources that a species is able to use, and the range of conditions that it can tolerate
what happens when niches of two species overlap?
interspecific competition
asymmetric competition
one species has greater fitness reduction than other species
symmetric competition
when the fitness reduction in both species is approximately the same, or equal
competitive exclusion
the competitive exclusion principle states that it is not possible for species with the very same niche to coexist.
fundamental niche
the total theoretical range of resources, habitats, and conditions used or tolerated when there is no competition
realized niche
the portion of the fundamental niche that a species actually occupies the resources, habitats, and conditions used/ or tolerated when there is coemption
niche differentiation
an evolutionary change in the traits of species that reduces the amount of niche overlap (also called resource partitioning) (reduced comp)
character displacement
evolutionary change in the traits of the species during the process of niche differentiation
consumption
+/- interaction that occurs when one organism eats another. it increases the fitness of one organism and decreases the other
parasitism
is the consumption of tissues or nutrients from another organism or host
endoparasite
parasite living on the inside of its host
Ectoparasites
Parasites that feed on external surface of host.
Parasitoids
a parasitoid lives freely as an adult, but is an endoparasite as a larva. In contrast to parasites, they always kill their host
constitutive or standing defenses
defenses that are always present (camo, schooling, mimics, weaponry)
inductile defenses
only present when a predator or consumer is present
aposematic coloration
a bright warning of dangerous or noxious defenses
Mullerian mimicry
harmful species resemble each other to make predators learn to avoid them
Batesian mimicry
A type of mimicry in which a harmless species looks like a species that is poisonous or otherwise harmful to predators.
the 4 key elements of community structure
total number of species
sum of interactions
relative abundance
physical attributes of the community
species richness
the number of different species in a given area
species abundance
The number of individuals within a species (or each different species) in an area
species diversity
H' = -∑pi ln pi
keystone species
A species that influences the survival of many other species in an ecosystem
generalists
consumers that have a varying diet(increase diversity)
ecosystem engineers
a keystone species that causes the physical changes in the environment that affect community structure
keystone prey
can maintain numbers despite being predated upon
Note
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