Ecology Test 2

Front 1

Predation

Back 1

one animal species eats all or some of a second animal species

Front 2

positive interactions/ facilitation

Back 2

interactions between two species that benefit at least one of the species and do not harm the other

Front 3

Mutualism/symbiosis

Back 3

when both species derive benefits from the association, win-win

Front 4

commenalism

Back 4

one species gains while there is no harm to the other, win-neutral

Front 5

mycorrhizal fungi and plants

Back 5

plants give sugars,

fungi- surface area, break down stuff and take it up,

both benefit

Front 6

Pollination

Back 6

mutualism

pollinatior benefits from stable food source

plants benefit through efficient sexual reproduction

jewelweed- landing pad

cardinal flower- long nectar tube

carrion flower- rotting mean scent

Front 7

Pollination Syndrome

Back 7

The convergence of unrelated plants on similar morphologies that attract the same kind of pollinator

Front 8

Orchids

Back 8

family orchidanceae

~25000 species

highly specialized pollination systems

co-evolution with pollinators

deceiving pollinators

Front 9

bees & coffee

Back 9

self-pollnating plants, protected from pollinators in agriculture

study showed pollinator activity increase coffee yield

increased hybrid vigor

Front 10

ants and acacias

Back 10

Acacia: protection from herbivores and other plants

acacia ant- source of food and shelter

acacias without ants ofter grow slowly and tend to perish

no chemical defenses

Front 11

foundation species

Back 11

dominant species that for the habitat that shelters many other species

ex- coral reefs, overstory trees, mangrove trees

Front 12

salt marshes

Back 12

emergent vegitation

mussles also living

-deposits feces

-provide plants with nitrogen and phos

fidler crab

-burrows into ground with a lot of H2O

-introduces O2 to H2O

-cellular respiration

add on biomass, decrease erosion

Front 13

Balancing + and - interactions

Back 13

graph

Front 14

example: nurse plants

Back 14

plants the provide some sort of protection to other plants during development (usually improve water balance)

Interaction changes over time +/0 to +/-

Example: Saguaro cactus with nurse plants blue palo verde

Front 15

overcompensation hypothesis

Back 15

moderate grazing wil stimulate biomass production

ex:

1. plant sagebrush in a common garden

2. subject to moderate, severe, and no browsing

Front 16

white bark pine and clarks nutcracker

Back 16

nutcracker eats seeds and digests them, they also plant some seeds

hide and store to eat late, but leave some for planting

Front 17

population regulation

Back 17

the maintenance of a population within a restricted zone of abundance so that the species neither becomes extinct nor increases without limit

-no population increases without limit

-abundance varies from habitat to habitat

Front 18

determining equilibrium population density

Back 18

principle: no closed population stops increasing unless either the birth rate or death rate changes with density

-a population in a closed system will increase until it reaches equilibrium point (birth=death)

Front 19

density dependent

Back 19

if death (or birth) rate per capita increases as density increases

Front 20

density independent

Back 20

death rate/birth rate does not change as density rises

Front 21

inverse density dependent

Back 21

opposite of directly density dependent rates, can never lead to an equilibrium density

Front 22

spatial variation in Abundane

Back 22

Principle: differences between two populations in equilibrium density can be caused by variation in either density- independent or dependent rates of birth and death

Front 23

measuring birth and death rates

Back 23

1. specify time interval

2. specify base population (per capita or per # population)

Front 24

intrinsic and extrinsic factors

Back 24

in: sex, age, physiology, behavior, genetics

ex: predators, food supply, disease, parasites, weather, shelter

Front 25

limitation

Back 25

a factor that produces a change in average or equilibrium density

Front 26

regulating factor

Back 26

a factor that results in an increase in % mortality as population density increases (density dependent)

Front 27

Potential Regulating Factor

Back 27

does not stop population growth

Front 28

actual regulating factor

Back 28

does stop population growth

Front 29

Allee effect

Back 29

produce instability in populations, invrese density dependence at low density

could be harmful to have overcrowding

instability

inverse density dependence at low density

Front 30

Glanville fritillary butterfly

Back 30

most populations are small (5-50)

45% of local populations became extinct in 2-yr period

smaller patches= smaller population= high probability of exinction

Front 31

Additive Mortality

Back 31

for an increase in mortality, total mortality increases by a constant amount

Front 32

compensatory mortality

Back 32

many environmental factors affecting mortality

below a threshold mortality rate, any change in losses has no effect on total mortality

Front 33

self thinning rule

Back 33

applies to plants and organisms with plastic growth rates

relationship between individual plant size and density in uniform-aged populations of a single species

(-4/3 boundary rule)

Front 34

source population

Back 34

net access of reproduction over mortality

population potential to grow infinitely

Front 35

sink population

Back 35

net excess of mortality over reproduction

potential to reach extinction

Front 36

source to sink population

Back 36

habitat fragmentation

Front 37

does natural selection affect population regulation?

Back 37

myxamatosis in rabbits

coevolution of virus and rabbit

affected population abundance

Front 38

balance of nature

Back 38

idea: the numbers of plants and animals were fixed and in equilibrium

modern view: shifting balance between populations that are affected by predators, competitors, diseases and mutualists, which are influences by changing weather and human activity

Front 39

intrinsic regulation

Back 39

precocial- ready to live

altricial- need support by parent(s)

Front 40

succession

Back 40

the universal process of change in communities and the order in which species replace one another

Front 41

directional change

Back 41

usually occurs in disturbed landscapes

one major group replaces another (Ex: trees replace grasses)

major focus on successional studies

Front 42

cyclical change

Back 42

occur on a small scale

replacement after death of individual or individuals

Front 43

seral stages

Back 43

the sequence of vegetation stages through which succession moves over time

Front 44

format of succession

Back 44

bare ground ---primary-> pioneer seal stage --> seal stages ---secondary-> climax

Front 45

primary succession at mt st helens

Back 45

1)Blast zone- vegetation blown down

2)pyroclastic zone- volcanic gas, pumice, and ash (North)

3) Mudflow zone- including ash deposits (South, east west)

1)seed size--> bigger establish better

2)dispersal ability--> smaller disperse better

Front 46

facilitation model

Back 46

A--+-->B--+-->C--+-->D><

key idea:climax

Front 47

mono climax hypothesis

Back 47

all processes in succession will lead to formation of climax community

at each seal stage, the dom. species modifies the environment to make it more suitable for other species

Front 48

inhibition model

Back 48

diagram

key idea: initial floristic composition

whoever is there first wins.. until they die

short lived replaced by long lived species

Front 49

tolerance model

Back 49

diagram

key idea: species are replace by others that are more tolerant of limiting resources

intermediate between facilitation and inhibition

can start anywhere

Front 50

modeling succession

Back 50

graph from class

Front 51

climax

Back 51

the final stage or stable community in a successional series. it is self perpetuation and in equilibrium with the physical and biotic communities

Front 52

mono climax theory

Back 52

every region has only one climax community toward which all communities are developing

Front 53

polyclimax theory

Back 53

many different climax communities in a given area (dependent on moisture, soil nutrients and animal activity, etc.)

Front 54

climax-pattern hypothesis

Back 54

A natural community is adapted to the whole pattern of environmental factors in which it exists.. allows for community of climax types, varying gradually along environmental gradients

Front 55

cyclical patch dynamics

Back 55

whole community moves slowly toward climax

local (patch scale)- experience rapid, cyclical changes (ex. heather and lichen)

Front 56

bracken fern patch dynamics

Back 56

fire resistant

underground rhizomes

spreads vegetatively

vigorous "front" of invading bracken fern

die back at the rear

Front 57

forest gap dynamics

Back 57

codominance

large gaps- large amounts of sunlight- maples are quicker to the punch, but these larger gaps are rare

beeches are good at being understory

frequent gaps= more maples in understory

Front 58

measuring biodiversity

Back 58

3 levels:

Genetic diversity

species diversity

community diversity

Front 59

richness

Back 59

number of resident species

Front 60

evenness

Back 60

relative abundance of resident species

Front 61

heterogeneity

Back 61

combination of richness and evenness

Front 62

alpha diversity

Back 62

within the environment

Front 63

beta diversity

Back 63

between habitats

how many species added when combining

Front 64

biodiversity today

Back 64

estimate 13-14 million species on earth

only 13% of these have been formally described and named by taxonomists

Front 65

tropical biodiversity

Back 65

general trend: biodiversity increases from the poles to the equator

Exceptions to this helps us understand other ecological factors that influence biodiversity

Front 66

hotspots of biodiversity

Back 66

linked with patterns of geographical isolation from continental drift

determined by number of endemic species

not restricted to tropics, but hotspots often occur in these regions

Front 67

what caused differences in biodiversity?

Back 67

evolutionary speed

geographic are

interspecific interactions

ambient energy

productivity

disturbance

Front 68

evolutionary speed

Back 68

more time and rapid evolution permits evolution of new species

more time: tropical biotas are mature and have more time to experience evolutionary changes (temp/polar are immature from glaciation and climate shifts)

Rapid evolution: warm, humid conditions support shorter generation time, higher mutation rates

Front 69

evolutionary speed at lake baikal

Back 69

25 million year old lake

deepest freshwater lake in the world

contains 5800 species of benthic macroinvertabrates

Front 70

Geographical Area

Back 70

-larger areas are physically/biologically complex habitats provide more niches

-tropics have larger land area than temperate zones, contain more & varied habitats

-tropographic Relief: mountanious regions introduce mammal diversity by providing different niches and by geographical isolation

-not the small for tree diversity

Front 71

interspecific interactions

Back 71

-competition affects niche partitioning, predation delays competitive exclusion

-more competition produces more specialized organisms and produces species with smaller niche breadths and/or higher niche breadths and/or higher niche overlaps

-population regulation by predators decreases competition, but increases diversity

Front 72

ambient energy

Back 72

fewer species tolerate climatically unfavorable conditions

energy availability maintains species richness gradients

climate determines availability (solar radiation, temp, water)

can be measured by evapotranspiration rates.. consider radiation, temp, water

Front 73

Ambient energy- coral reefs

Back 73

warm water coral reefs-more available energy, species rich

cool water coral reefs- less available energy, fewer taxa

Front 74

Productivity

Back 74

Idea: greater production will result in greater biodiversity

no proof for this

Front 75

intermediate disturbance hypothesis

Back 75

moderate disturbance delays competitive exculsion

hypothesis predicts that species diversity will be highest at intermediate levels of disturbance

if disturbances are frequent, community remains at pioneer stages of succession

if disturbances are reduced, succession proceeds and richness reaches a peak

Front 76

saturated comunities

Back 76

no more species can be squeezed in

all niches have been filled

Front 77

community organization

Back 77

what species are present, how abundant, who eats who, how do they interact?

3 approaches to understanding community organization

1. measure biodiversity

2. define feeding roles

3. determine importance of individual species

Front 78

equilibrium communities

Back 78

stability

-measured by time it takes for a community to recover from disturbance

-fluctuation in comm. size

-presistance of comm. over time

major characteristics

-many biotic interactions

-rare species invasions

-rare weather catastrophes

Front 79

non equilibrium communities

Back 79

species operate individually

climate catastrophes are frequent

composition highly variable- result of frequent immigration/emmigration

Front 80

food chains

Back 80

trophic levels:

1)Producers

2)Primary consumers

3)secondary consumers

A given species may occupy one or more trophic level

often organized by size

Front 81

food chain length

Back 81

typical range is 1 to 9 links

most common number is 5 links

why?- energetic and stability hypothesis

constant proportion pred to prey (1:2.5)

Front 82

energetic hypothesis

Back 82

limited by inefficiency of energy transfer

longer chains in productive envirnoments

Front 83

stability hypothesis

Back 83

longer chains- less stable, fluctuations in low levels cause high levels to extinct

Front 84

guilds/functional groups

Back 84

groups of species exploiting a common resource base in a similar fashion (bees&hummingbirds)

Advantages:

1)focus on potentially competing species, regardless of taxonomy

2) Managable units of functional groups

3)Represent basic building blocks of communities

Front 85

Guilds case study: Eastern deciduous forest

Back 85

62 tree species

9 guilds determines by regeneration ecology

Front 86

pioneer guilds

Back 86

regenerate quickly in disturbed areas

Front 87

opportunistic guilds

Back 87

regenerate in a wide variety of conditions

Front 88

persistent guilds

Back 88

regenerate in shade and are long lived

Front 89

guild concept generalizations

Back 89

1) some species serve as a functional equivalents w/in a community

2) # of functional roles is small in relation to # of species

3) Limit to number of species that can fill and functional role

4) species within guilds fluctuate in abundance in such a way that total biomass/density of a guild remains stable