BioL 150 final

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

1. total number of species
2. sum of interactions
3. relative abundance
4. 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