Ecology Pt.2

Animal Behavior

the study of how animals move in their environment, how they socially, how they learn about their environment, and how an animal might achieve cognitive understanding of its environment

Kinesis

the nondirectional movement of an organism or cell in response to a stimulus

Taxis

an innate behavioral response by an organism to a directional stimulus.

Classical conditioning

arbitrary stimulus associated with particular outcome

Operant conditioning

a type of associative learning that’s based on reinforcement or punishment to modify a conditioned behavior

Cognition

process of knowing that involves awareness, reasoning, recollection, judgment

Population growth formula

dN/dT = B - D (dN = change in pop size; dT = change in time; B = birth rate; D = death rate

exponential population growth

ideal conditions; population grows rapidly

Exponential Growth Equation

dN/dT = rN (dN/dT change in population; r = growth rate of pop.; N = population size)

Logistic Growth

population expansion decreases as resources become limited; levels off when carrying capacity is reached

Logistic growth formula

dN/dt = rN((K-N)/K) (dN/dT change in population; r = growth rate of pop.; N = population size; K = carrying capacity)

K-selection

* Population close to carrying capacity
* Live around K
* High prenatal care
* Low birth numbers
* Good survival of young
* Density-dependant

r-selection

* Maximize reproductive success
* exponential growth
* little or no care
* high birth numbers
* poor survival of young
* density independant

Density- dependant factors

factors that affect the population based on density

* Predation
* disease
* competition
* territoriality
* toxic wastes
* physiological factors

Density-independent factors

factors that affect the population size and doesn’t depend on density or size

* natural disasters (fire, flood, weather)

Carrying capacity

* the number of people, other living __organisms__, or __crops__ that a region can support without environmental degradation.
* when close to it, resources become more partitioned, resulting in niche partitioning

Niche partitioning

decrease in competition over limited resources because each species is accessing the resource in different ways

Mark & Recaptured Method

used to estimate the size of a population

Mark & Recaptured Method Formula

N = MT/R (N = predicted pop. size; M = Marked; T = total # of organisms in second collection; R = # of recaptured that are marked)

Interspecific interactions

interactions between species

Competition (-/-)

the direct or indirect interaction of organisms that leads to a change in fitness when the organisms share the same resource; bad for both species

Predation (+/-)

the preying of one animal on others

Herbivory - (+/-)

the consumption of plant material by animals

Facilitiation - (+/+ or +/0)

create new landscapes or habitats (ex: beaver or sea otters)

Symbiosis

2+ species live in direct contact with one another

Parasitism (+/-)

\n parasites attatches to and harms organisms by draining nutrients

Mutalism - (+/+)

both species benefit (ex: bee and flower)

Commensalism

species 1 benefits, 2 isn’t affected

Keystone species

exert control on community structure by their important ecological niches - **increase community diversity** (wolves and sea otters)

Facilitating Species

one species positively impacts the fitness of another (intertidal mussels)

Simspon’s Diversity Index

diversity based on species richness & relative abundance; higher diverse communities are more resistant to invasive species

Simpson’s Diversity Index Formula

D = 1- Σ(n/N)^2