Ecology 3

Community

a group of species that occupy a given area, interacting directly or indirectly with one another

Species interactions are classified by their…

reciprocal effects on each other

Neutral

Neither benefit

Mutualism

both benefit

Commensalism

One benefits and one is not effected

Competition

both harmed by competing for a resource

Amensalism

only one harmed

Population is controlled by…

the rate at which individuals are added to B,I or lost from E,D in the population

Factors such as predation, parasitism, parasatoidism influence whether beneficial and detrimental…

the birth and death of population levels

Species interactions can function as agents of…

natural selection

Co-evolution

two or more species affect each others evolution

Thwart adaptive changes

predator-prey/ parasite- host

Magnify adaptive changes

mutualisms

Adaptive radiation

the process by which one species gives rise to multiple species that exploit different features of the environment

Diffuse coevolution

groups of species interact with other groups of species, leading to natural selection and evolutionary changes that cannot be identified as example of specific

Competition results…

when resources are limited

Intraspecific competition

utilization of the same resources by members of the same species

Interspecific competition

Utilization of the same resources by 2+ different species

What type of competition reduces fitness

interspecific

Consumption competition

shared food resource

Encounter competition

non-territorial meetings that negatively effect one or both participants

Pre-emptive competition

preclude establishment

Overgrowth competition

inhabit access to essential resource

Chemical interactions

chemical growth inhibitors or toxins

Territorial competition

behavioral exclusion of others from a defended territory

Density dependence

regulation of population growth by mechanisms controlled by the size of the population; effects scale with population size

Key factors of density dependance

1. resource availability

2. predation

3. disease and parasites

Ecological niche

a species position within an ecosystem, including he range of conditions necessary for persistence and its ecological niche

Fundamental niche

niche that is potentially occupied by a species

realized niche

part of fundamental niche that is actually occupied by a species

Competitive release

when a species expands its niche, habitat, or population size after the removal of a competing species

Enemy release hypothesis

species can become invasive in new environments because they are freed from their natural enemies that regulated their populations in their native ranges

Resource partitioning

the division of limited resources by species to help avoid competition in an ecological niche

Character displacement

is a shift in morphological, behavioral, or physiological character as a result of niche partitioning due to competition

What directly influences physiological processes related to growth and reproduction?

environmental factors

Predator and prey population function as density- dependent regulators of each other through effects on…

mortality and death rates

Predator- prey interaction results in…

population cycles

Functional response

change in rate of exploitation of a prey species by a predator in relation to changing prey density

The greater the number of prey, the more predator eats is an example of…

functional response

Numerical response

change in predator population size in response to change in density of its prey

Type 1 functional response…

predators are never full and never stop feeding

predators are NOT limited by handling time

(zooplankton)

Type 2 functional response

predators are limited by handling time

(most common in predators)

Type 3 functional response

predators are limited by handling time

imperfect detection

(refuge from predation- coral)

Optimal foraging theory

natural selection favors “efficient” foragers, individuals that maximize their nutrient intake per unit of effort

Costs

time and energy expended for foraging

Benefit

increased fitness as measured in terms of energy or nutrition gain, which is assumed to correlate with fitness

Small prey

easy to handle, but too little energy gained

Large prey

hard to handle relative to energy gained

Coevolution

two or more species reciprocally affect each others evolution

Prey adaptations to evade predation…

armor

Predator defense

characteristics to avoid being detected, selected, and captured by predators

Chemical defenses

substance utilized by prey to repel, deter, injure, harm, distract, or prevent detection by predators

Coloration

1. camouflage

2. warning

3. mimicry

Aposematism

use of warning coloration to inform potential predators that an animals is poisonous, venomous, or otherwise dangerous

Mullerian mimicry

two unrelated and both unpalatable organisms display similar aposematic colorations

Batesian mimicry

edible animals living in the same habitat as inedible species sometimes evolve a coloration that resembles the warning coloration of the toxic species, also predator phenotype

Mimicry

close external resemblance of an organism with a feature of their environment

Grouping

by maintaining tight, cohesive groups, prey make it difficult for any predator to obtain a victim

Avoidance Behavior

can be spatial or temporal and avoid predation

Landscape of fear

the spatial variation in prey perception of predation risk

predation risk

the likelihood of prey animal being killed by a predator

Secondary compounds

chemicals that are not involved in the basic metabolism of plant cells to function to deter herbivory

Three general methods…

ambush, stalking, and pursuit

Ambush

lie in wait for prey to come by where they are waiting

• low energy output, low success rate

Stalking

deliberate hunting method with a quick attack

• search time is long, pursuit time is short

Pursuit

predators chase down prey

• search time is short, pursuit time is long

Traps and lures

used to attract a pray, this is a form of ambush

Symboises

a long-term interaction between two or more organism of different species living close physical association

Parasite

a consumer that feeds intimately on one host during a particular life stage

Microparasites

viruses, bacteria, protists

Microparasites

viruses, bacteria, protists

Ectoparasite

live on a hosts exterior

Endoparasite

live within the host

Hemiparasite

photosynthetic

• partial dependence

Holoparasite

non- photosynthetic

• complete dependence on the host

Direct transmission

a parasite is transferred from one host to another without the involvement of an intermediate organism

Passive transmission

a cyst/spore/egg contacts or is ingested by a host

Active transmission

a host-seeking, free-living parasite stage

contact transmission

transfer when infected and uninfected host

Indirect transmission

parasite involved an intermediate host

Trophic transmission

when predator host consumes an infected prey host

Host defenses

reduce parasitic invasion

ex. avoidance/ grooming and preening

Combat parasitic infection

inflammation and isolation and immune response

Antigen

a protein on a foreign object that stimulates the immune system to produce antibodies

ex. virus, bacteria, toxin

ways that parasites have adapted…

difficulty to detect

short generation time (r-selected)

immune evasion

Infection

heavy load of parasites

Infectious disease

the illness that results from infection and can kill the host and lower reproduction

Zoonotic disease

passed from animals to humans

Bubonic plague

bite of flea infected with bacterium → caused human population to crash

Emerging infectious disease

those that have recently appeared within a population, or whose incidents geographic range is readily increasing

Mutualism can be classified by…

duration, dependency, and benefits

Duration of interaction

symbiotic vs non-symbiotic

Dependency of partnership

obligate vs facultative

Types of benefit

resource food, service-resource, service- service

Facultative

can survive and reproduce with the association

Obligate

cannot survive or reproduce without the association

How did mutualism evolve?

parasitism → commensalism → mutualism

Mutualism benefits

enhance the transfer of nutrients

Commentionalism

species interaction which is beneficial for one party and does not affect the other

Amensalism

a species interaction in which one species is adversely affected but the other is unaffected

• often used to deserve strongly asymmetrical competitive interactions