Ecology Exam 3

The study of behavior; all the ways organisms interact with other organisms and the physical environment

1. Mechanism of behavior
2. Development/Ontogeny of behavior
3. Function/Adaptive value of behavior
4. Evolution/Phylogeny of behavior

“how”

“why”

Comes from an animals’ heredity

Comes from watching other organisms and life experiences

the process by which an organism acquires a mental representation of its environment.

the process through which organisms acquire information about relationships between events or entities in their environment

learned by observing and imitating the behavior of others

a sudden realization of a solution to a problem

food acquisition

information exchange between organisms

interactions between members of the same species

1. reduced predation risk/decreases individual vigilance

2. access to mates

3. resource sharing

4. information center

1. Increased visibility to predators

2. disease transmission

3. increased competition

1. cooperation - positive-positive

2. selfishness - positive-negative

3. altruism - negative-positive

4. spitefulness - negative-negative

positive-positive, benefits donor, favored by selection

positive-negative, benefits donor, favored by selection

negative-positive, can indirectly benefit donor, can be favored by selection

negative-negative, benefits no one, not favored by selection

donor benefits when recipient reciprocates in future

1. kin selection

2. delayed direct fitness benefit

3. reciprocal altruism

occurs when parents and their offspring differ in the optimal level of parental investment

organism kills and eats prey organism

prey abundance

A species introduced to a region it has not historically existed

An introduced species that spreads rapidly and has negative effects on the ecosystem

Sometimes a newly introduced invasive species can mitigate or completely eliminate the effects of another invasive in the ecosystem (cactus moth vs. prickly pear)

Plant biomass

predation

coexistence

1. Behavioral - limits detection, pursuing, catching

2. Crypsis - limits detection, camouflage

3. Structural - mechanical or body shape

4. Chemical - poison or venom, can spur mimicry

1. Batesian

2. Mullerian

when a species mimics the warning signals of another species without having the characteristics that make it undesirable to their shared predator, nonvenomous mimics venomous

two or more noxious animals develop similar appearances as a shared protective device, the theory being that if a predator learns to avoid one of the noxious species, it will avoid the mimic species as well

predators

They typically don’t kill their host. Those that do kill their host do it slowly

live on the outside of the host organism ex. ticks

live inside of the host organism, often microscopic ex. tapeworm

partially embedded in the host’s body

requires host to complete its life cycle

does not require host

Destroy host’s ability to reproduce, redirects energy to parasite

vector is not required ex. lice

Most hosts not infected, others have heavy parasite loads, typically seen in direct transmission parasites

transmission via consumption by host

third party required for transmission between hosts

No, vectors carry parasite, but do not become infected

Laying eggs in other species’s nests, siblings are outcompeted

Males are reduced in size, dependent on females, typically permanently attached

1. Plants obtain carbon from photosynthesis
2. Fungi on roots trade nutrient absorption for carbon
3. Chlorophyll-less plants take carbon from fungi

are typically small endoparasites

1. exposed to a wide variety of viruses

2. Hyperactive immune system, can fight off invaders

3. Less virulent invaders may be ignored and incubated

Human impacts

an interaction between organisms or species in which both require the same limited resource

1. population dynamics

2. community structure

3. diversity

4. selection

occurs when two or more species must share a limited resource

between multiple species

A population increases until the supply of the most limiting resource prevents it from increasing further

1. the more efficient species is likely to be the winner of a competitive interaction

2. competition is asymmetrical

3. the limiting resource is environment- dependent

They cannot coexist indefinitely

species competing for the same resource cannot coexist

differences in resource acquisition prevent competitive exclusion

differentiation of competitive ability in time

1. abiotic conditions

2. disturbance

3. interspecies interactions

A special case of directional selection caused buy long periods of intense competition

Individuals consume a resource and drive down the abundance of a
resource to the point that other individuals cannot persist, favors species that access resource first

Antagonistic interactions that result in resource
exclusion for the subordinate competitor, favors large, strong adults

Two species have a negative effect on each other through a common enemy including a predator, parasite, or herbivore, Species A increases = more predators = Species B declines

symbiosis that is beneficial to both organisms involved

1. Food

2. Shelter

3. Reproduction

4. Dispersal

5. Protection

two individuals share/exchange resources

one individual provides a service (cleaning, seed dispersal, etc) in exchange for a resource (food, shelter, etc.) from the other individual

two individuals provide a service for one another; very rare

required for the survival of the species

beneficial but are not required for survival

organism receives benefit at cost to partner

one species benefits, another
does not, but neither are harmed

attachment to another species for travel

living in the burrow, nest, other living structure of other species

one species has a positive effect on another

abiotic gradients

Groups of species interacting in the same place at the same time,
can be delineated geographically at large scales

Sharp changes in environmental conditions and species composition over a relatively short distance

1. taxon

2. guild (use the same type of resources in similar ways)

3. functional group (share similar characteristics)

species depend on each other to exist, Clementsian community
concept

species do not depend on each other to exist, Gleasonian community concept

graphically display richness and evenness

number of individuals of a species

proportion of the total community made up by each species

tells you how diverse the species in a given community are, rises with the number of species and the evenness of their abundance, Ranges from 0 to ln(S

proportions of species or functional groups present on a site, more equal species in proportion to each other the greater the evenness of the site, site with low evenness indicates that a few species dominate the site, Ranges from 0 to 1

within the site

between sites

across landscape, determined by diversity within sites and
differentiation between sites

1. Resources

2. Habitat diversity

3. Keystone species

4. Disturbance

a series of indirect effects that “cascade”
through a community, top-down control

Other positions where a community is stabilized, communities don’t have just one “optimal” composition

a directional and predictable change in the [plant] community over time

initiates life