Ecology Quiz pt.2

Interspecific Interactions

predation, competition, parasitism, mutualism, commensalism, amensalism

Predation

short term relationship where 1 organism gains fitness by consuming the other, ex. lion and zebra

Competition

2 different species fighting over a limited resource, ex. lion and hyenas

Parasitism

long term relationship where one benefits (parasite) and the other is harmed (host) , ex. brown headed cowbird-brood parasite, fleas and dogs

Mutualism

long term relationship where both organisms benefit , ex. plovert and crocodile

Commensalism

long term relationship where one benefits and other is not affected , ex. shark and romora

Amensalism

one individual is harmed and other is not affected , ex. elephant stomping on grass

3 affects on interactions

1 - per capita growth rates (r) of at least 1 species is modified 2 - average population density of at least 1 species is altered 3 - interactions with negative effects can cause local extinction

competitive exclusion principle

no 2 species can occupt the same niche at the same time

competitive exclusion principle example

rock barnacles and stellate barnacles cannot have overlapping niches

Food web represents -----

the flow of energy through an ecosystem from 1 trophic level to another

most species interact with other species to form a web,

interactions based on trophic (energy) and form many different levels

Effects of species diversity on health/fragility of ecosystem

fewer species = higher dependence upon other species ecosystems with higher species diversity can absorb loss of a single species

What is one ecosystem that is more fragile than forest

desert

Trophic Cascade Effect

effects of the abundance of species at one trophic level at other trophic level , ex. overfishis of cod in northwest atlantic, led to explosion of smaller species like herring and shrimp, which reduced zooplankton population

non-native species

exotic introduced species

invasive species

non-native species that have a negative impact on the fitness of native species

example of introductions with negative effects on native populations

Kedzu and lionfish

example of introductions with positive effects on native populations

gizzard shad in claytor lake

example of introductions with neutral effects on native populations

Pheasant

How can predator-prey relationship cause evolutionary arms race (example)

lion vs. zebra, zebra evolves to escape lion (predator), lion evolves to catch zebra, this keeps repeating with many improvements to each species

how can intraspecific competition increase carrying capacity for a species

as competition increases the less favorable phenotypes die off, more fit individuals reproduce and maximize their resources, increasing carrying capacity through stabalizing selection

community

a group of species that co-exist and interact within a geographic area

3 parts of community structure

Species Competition, Number of different species, Relative abundance of each species

Turnover

changes in species composition

succession

a natural, predictable, and gradual change after a disturbance that ultimately leads to a community that resembles the original , ex. secondary succession, grass growing back after forest fire

ecological transition and example

a transition from one ecological community to a different one following a disturbance , ex. elephant creation of desert

GPP

gross primary productivity: total amount of energy that producers capture and convert into chemical energy per unit time

NPP

net primary productivity: the amount of energy stored in primary producer's tissues per unit time (energy available to consume)

NPP =

GPP - Respiration

transfer of energy from one trophic level to the next =

10%

2 parts of species diversity

species evenness and species richness

Species Evenness

a measure of the similarity of abundances of species in a community

Species Richness

total number of species in a community

Species diversity index equation

D= 1 - (En(n-1) / N(N-1))

Why does species richness vary with latitude

species diversity highest at tropics (equator), climate most stable in tropics, as distance from equator increases climate stability decreases . becasue equator ideal area (temperture is same all year)

what is Theory of Island Biogeography

how new island is colonized

6 parts of theory of island biogeography

1: islands gain species by colonization from nearby ecosystems 2: the rate at which new species arrive declines as the island fills with species 3: extinction rate increases as the island fills with species 4: species richness stops changing when extinction rate = colonization rate 5: population size decreases as island size decreases. extinction rate is higher for small islands 6: colonization rate and species richness are higher on close islands that on distant islands