es10 species, communities.pdf

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Study Questions: Evolution, Species

Interactions, and Bio logical Communities

1. Explainevolution,includingtermssuchasadaptation,naturalselectionandmutation.

1. Howand

why

might

new

species

arise?

Explain

the

terms

sympatricandallopatricspeciation.

1. Compareandcontrastcompetition,mutualism,commensa sm,pre a on,an paras sm.

2. Compareandcontrastrandkreproductivestrategies.

1. ExplainthedifferencebetweenSandJgrowthcurves.

2. Explainthedifferencebetweenabundanceanddiversity.

3. Describetheprocessofsuccession.

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Species: genetically similar organisms that can

successfully reproduce with each other

Theecologicalnicheisaspeciesrole

andenvironment

Habitat:theplaceorsetofenvironmentalconditionsinwhichaparticularorganismlives.

Ecologicalniche:theroleplayedbyaspeciesinabiologicalcommunityandthetotalsetof

distribution.

33

Competitiveexclusionprinciple:notwospeciescanoccupythesameecological

nicheforlong.

34

What Determines Where Species Live?

Factors such as

Tolerance limi ts: minimum and maximum levels of

temperature, nutrient supply, etc

Noorganisms

Feworganisms

Lower limitof tolerance

Abundance of organismsFew

organismsNo

organisms

Upper limitof tolerance

Range of Tolerance

Population

siz

Low HighTemperature

Zone ofintolerance

Zone ofphysiological stress

Optimum range Zone ofphysiological stress

Zone ofintolerance


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Selective pressures and random mutations lead to

Natural selection: the process in which better

competitors reproduce more successfully

Adaptat ion: changes that allow an organism or

population to survive in its environment

Some of these changes are passed on genetically

Evolution: gradual changes in species that result

from competition for scarce resources

Speciation: the development of a new, distinct species

Speciation can occur as a result of:

New food or other resource

New stress (climate or predator)

Geographic isolation

Behavioral isolation

Geographicisolationresultsinallopatric

speciationspeciesariseinnonoverlapping

geographiclocations.

speciationspeciesariseinthesamelocation

astheancestorspecies.

310

Geographic

isolationisa

mechanismin

allopatric

speciation.

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4 of the 13 Galapagos Finch Varieties


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Taxonomydescribesrelationshipsamongspecies

Taxonomy: thestudyoftypesoforganismsandtheir

relationships.

313 314

Competition

Organisms compete for:

Nutrients, space, mates, etc.

Species Interactions

n ra- an n er-spec c compe on ex s

Predation

Predator: organism that feeds directly upon another

living organism (prey)

Scorpion Fish

Americanbittern

Co-evolution: predator and prey evolve in response

to each other (camouflage, mimicry) Camouflage

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Monarch Viceroy

Lon horn Beetle

Symbiosis: 2 or more species living together

Commensalism : 1 species benefits, 1 is neutral

Mutualism : both members benefit Parasitism: 1 species benefits, 1 is harmed

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TheGrowthofSpeciesPopulations

Exponentialgrowth: populationgrowthwith

nolimits; itresultsinaJgrowthcurve

whengraphed.

Logisticgrowth: limitedpopulationgrowth;

itresultsinaSshapedgrowthcurvewhen

graphed.

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Jcurveofexponentialgrowth

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Scurveoflogisticgrowth

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Ideal, unlimited population growth is exponential

Actual growth slows down as resources become limited

J curve S curve

Limitstopopulationsize

Densitydependent,meaningaspopulationsize

increases,theeffectintensifies.Withalarger

population,thereisanincreasedriskthatdisease

orparasiteswillspread,orthatpredatorswillbe

attractedtothearea.

Densityindependentlimitstopopulationareoften

nonbiological,capriciousactsofnature.A

populationisaffectednomatterwhatitssize.

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Reproductive Strategies

r-adapted species: use rapid, copious reproduction

K-adapted species: slower reproduction, fewer offspring

Speciesrespondtolimitsdifferently:

randKselectedspecies

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Diversity: number of different species within an area

Abundance: number of individuals of a species within

an area

The greater diversity in a community, the greater

resil ienc and stabilit of that communit

Communities

Community: all the populations that live and interact

in an area

Ecotones: boundaries between adjacent communities

CommunitiesAreDynamicand

ChangeOverTime

ClimaxcommunityThecommunitythat

developedlastandlastedthelongest.

Pr marysuccess on an t at s areo so a

sandbar,mudslide,rockface,volcanicflowis

colonizedbylivingorganismswherenonelived

before.

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Secondarysuccessionafteradisturbance,if

leftundisturbed,acommunitywillmaturetoa

characteristicsetoforganisms.

Pioneerspeciesthefirstspeciestocolonizea

commun ty npr marysuccess onon an .

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PrimarySuccession

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Invasive species: organisms not normally found in a

particular location that disrupt the local community

Hawaiian mongoose Polynesian rat

es10 species, communities.pdf

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