Ecology and BehaviorEcology and Behavior

EOC GOALS for this unit:EOC GOALS for this unit:

Develop an understanding of ecological Develop an understanding of ecological relationships among organismsrelationships among organisms

Develop an understanding of the behavior Develop an understanding of the behavior of organisms, resulting from a combination of organisms, resulting from a combination of heredity and environmentof heredity and environment

Interrelationships in EcologyInterrelationships in EcologyPopulationPopulationCommunityCommunityEcosystemEcosystemBiosphereBiosphere

PopulationPopulationMembers of the same species in a given Members of the same species in a given

area.area.Population growth and characteristics are Population growth and characteristics are

the study of population ecologiststhe study of population ecologistsThree Key Features of Populations A

population’s future survival is determined by its size, density, and dispersion.

Exponential Growth Growth Rate The rate of population growth is

the difference between the birthrate and the death rate.

Exponential Growth Curve A J-shaped graph in which the rate of population growth stays the same is known as an exponential growth curve. (increasing)

• Rapidly Growing Populations R-strategists grow exponentially when environmental conditions allow them to reproduce and this often results in temporarily large populations.

Exponential Growth in anr-selected species.

Logistic GrowthLogistic GrowthLeveling off at carrying capacityLeveling off at carrying capacityK = carrying capacity – the number of K = carrying capacity – the number of

organisms a population can sustain.organisms a population can sustain.Slowly Growing Populations = K-

strategists grow slowly, have small population sizes, and their population density are near the carrying capacity.

initial carrying capacity

(or K)

Logistic Growth of a K-selected Species

Community Community

All the populations that live together in a given areaAll the populations that live together in a given area Community interactions involve things like predator-Community interactions involve things like predator-

prey, symbiosis, and competitionprey, symbiosis, and competition Every organism in a community has the following:Every organism in a community has the following:

habitat: place where an organisms liveshabitat: place where an organisms lives niche: an organism’s job; all the resources that an organism usesniche: an organism’s job; all the resources that an organism uses

Type of habitat shapes a community’s structureType of habitat shapes a community’s structure

NicheNiche

Sum of activities and relationships in Sum of activities and relationships in

which a species engages to secure and which a species engages to secure and

use resources necessary for survival and use resources necessary for survival and

reproductionreproduction

Species InteractionsSpecies Interactions

Most interactions are neutral; have no effect on either Most interactions are neutral; have no effect on either

speciesspecies

Interspecific competition has a negative effect on both Interspecific competition has a negative effect on both

speciesspecies

Predation and parasitism both benefit one species at Predation and parasitism both benefit one species at

a cost to anothera cost to another

Symbiosis - Living together for at Symbiosis - Living together for at least some part of the life cycleleast some part of the life cycle

Commensalism, mutualism, and Commensalism, mutualism, and

parasitism are forms of symbiosis parasitism are forms of symbiosis Commensalism helps one species and has no effect Commensalism helps one species and has no effect

on the other on the other

Mutualism helps both speciesMutualism helps both species

Parasitism helps the parasite at the cost of the hostParasitism helps the parasite at the cost of the host

ParasitismParasitism

Parasites drain nutrients from their Parasites drain nutrients from their

hosts and live on or in their bodieshosts and live on or in their bodies

Natural selection favors parasites that Natural selection favors parasites that

do not kill their host too quicklydo not kill their host too quickly

PredationPredation

Predators are animals that feed on other Predators are animals that feed on other

living organismsliving organisms

Predators are free-living; they do not Predators are free-living; they do not

take up residence on their preytake up residence on their prey

Ecosystem Ecosystem

An association of organisms and their An association of organisms and their

physical environment, interconnected by physical environment, interconnected by

ongoing flow of energy and a cycling of ongoing flow of energy and a cycling of

materialsmaterials

Matter (Biogeochemical) Matter (Biogeochemical) CyclingCycling

The flow of a nutrient from the The flow of a nutrient from the

environment to living organisms and back environment to living organisms and back

to the environmentto the environment

Main reservoir for the nutrient is in the Main reservoir for the nutrient is in the

environmentenvironment

Three CategoriesThree Categories

Hydrologic cycleHydrologic cycleWaterWater

Atmospheric cycles Atmospheric cycles Nitrogen and carbonNitrogen and carbon

Sedimentary cycles Sedimentary cycles Phosphorus and sulfurPhosphorus and sulfur

Water (Hydrologic) CycleWater (Hydrologic) CycleAtmosphere

Ocean Land

evaporation from ocean

425,000

precipitation into ocean 385,000

evaporation from land plants (evapotranspiration)

71,000

precipitation onto land 111,000

wind-driven water vapor40,000

surface and groundwater flow 40,000

Figure 48.14Page 876

Carbon CycleCarbon Cycle

Carbon moves through the atmosphere Carbon moves through the atmosphere

and food webs on its way to and from and food webs on its way to and from

the ocean, sediments, and rocksthe ocean, sediments, and rocks

Sediments and rocks are the main Sediments and rocks are the main

reservoirreservoir

Carbon Cycle - LandCarbon Cycle - Land

photosynthesis aerobic respirationterrestrial

rocks

soil water

land food webs

atmosphere

peat, fossil fuels

combustion of wood

sedimentation

volcanic action

death, burial, compaction over geologic time

leaching, runoff

weathering

combustion of fossil fuels

Figure 48.16 Page 878

Nitrogen CycleNitrogen Cycle

Nitrogen is used in amino acids and Nitrogen is used in amino acids and

nucleic acidsnucleic acids

Main reservoir is nitrogen gas in the Main reservoir is nitrogen gas in the

atmosphereatmosphere

Nitrogen CycleNitrogen Cyclegaseous nitrogen (N2)

in atmosphere

NO3-

in soil

nitrogen fixationby industry

fertilizers

NH3-,NH4+

in soil

1. Nitrification leaching

uptake by autotrophs

excretion, death, decomposition

uptake by autotrophs

nitrogen fixation

leaching

ammonification 2. Nitrification

dentrification nitrogenous

wastes, remains

NO2-

in soil

food webs on land

Figure 48.21Page 882

Nitrogen FixationNitrogen Fixation

Plants cannot use nitrogen gasPlants cannot use nitrogen gasNitrogen-fixing bacteria convert Nitrogen-fixing bacteria convert

nitrogen gas into ammonia (NHnitrogen gas into ammonia (NH33))

Ammonia and ammonium can be Ammonia and ammonium can be

taken up by plantstaken up by plants

Human EffectsHuman Effects

Humans increase rate of nitrogen loss by Humans increase rate of nitrogen loss by clearing forests and grasslandsclearing forests and grasslands

Humans increase nitrogen in water and air Humans increase nitrogen in water and air by using fertilizers and by burning fossil by using fertilizers and by burning fossil fuelsfuels

Too much or too little nitrogen can Too much or too little nitrogen can compromise plant healthcompromise plant health

Energy Energy Flow in Flow in

EcosystemEcosystemss

energy input from sun

nutrientcycling

PHOTOAUTOTROPHS(plants, other producers)

HETEROTROPHS(consumers, decomposers)

energy output (mainly heat)

Consumers Consumers Herbivores-plants Herbivores-plants Carnivores-meat Carnivores-meat ParasitesParasites Omnivores-Omnivores-

meat/plants meat/plants DecomposersDecomposers Detritivores Detritivores

SPRING

rodents, rabbits

fruitsinsects

birds

SUMMER

rodents, rabbits

fruits

insects

birds

Seasonal variation in the diet of an omnivore (red fox)

Trophic LevelsTrophic Levels

All the organisms at a trophic level are the All the organisms at a trophic level are the

same number of steps away from the same number of steps away from the

energy input into the systemenergy input into the system

Producers are closest to the energy input Producers are closest to the energy input

and are the first trophic leveland are the first trophic level

Trophic Levels in PrairieTrophic Levels in Prairie

5th

4th

3rd

2nd

1st

Fourth-level consumers (heterotrophs):

Top carnivores, parasites, detritivores, decomposers

Third-level consumers (heterotrophs):Carnivores, parasites, detritivores, decomposers

Second-level consumers (heterotrophs):

Carnivores, parasites, detritivores, decomposers

First-level consumers (heterotrophs):

Herbivores, parasites, detritivores, decomposers

Primary producers (autotrophs):Photoautotrophs, chemoautotrophs

Food ChainFood Chain

A straight-line A straight-line

sequence of who eats sequence of who eats

whom whom

Simple food chains Simple food chains

are rare in natureare rare in nature

marsh hawk

upland sandpiper

garter snake

cutworm

plants

Tall-Grass Prairie Food WebTall-Grass Prairie Food Web

earthworms, insects

sparrow

vole pocketgopher

groundsquirrel

coyotebadgerweasel

spider

frog

snake

sandpiper crow

marsh hawk

grasses, composites

Ecological SuccessionEcological Succession

Change in the composition of species over Change in the composition of species over

timetimeClassical model describes a predictable Classical model describes a predictable

sequence with a stable climax communitysequence with a stable climax community

Types of SuccessionTypes of Succession

Primary succession - new Primary succession - new

environments environments

Secondary succession - Secondary succession -

communities were destroyed or communities were destroyed or

displaceddisplaced

Pioneer SpeciesPioneer Species

Species that colonize barren habitatsSpecies that colonize barren habitats

Lichens, small plants with brief life cyclesLichens, small plants with brief life cycles

Improve conditions for other species who Improve conditions for other species who

then replace themthen replace them

Climax CommunityClimax Community

Stable array of species that persists Stable array of species that persists

relatively unchanged over timerelatively unchanged over timeSuccession does not always move Succession does not always move

predictably toward a specific climax predictably toward a specific climax

community; other stable communities may community; other stable communities may

persistpersist

Cyclic ChangesCyclic Changes

Cyclic, nondirectional changes also shape Cyclic, nondirectional changes also shape

community structurecommunity structureTree falls cause local patchiness in Tree falls cause local patchiness in

tropical foreststropical forestsFires periodically destroy underbrush in Fires periodically destroy underbrush in

sequoia forestssequoia forests

Human Activities/Impacts on Human Activities/Impacts on EnvironmentEnvironment

Global WarmingGlobal WarmingHuman Population GrowthHuman Population GrowthPesticide UsePesticide UseSpecies EffectsSpecies Effects

Carbon in AtmosphereCarbon in Atmosphere

Atmospheric carbon is mainly carbon Atmospheric carbon is mainly carbon dioxidedioxide

Carbon dioxide is added to atmosphereCarbon dioxide is added to atmosphereAerobic respiration, volcanic action, burning Aerobic respiration, volcanic action, burning

fossil fuels fossil fuels Removed by photosynthesisRemoved by photosynthesis

Greenhouse EffectGreenhouse Effect

Greenhouse gases impede the escape Greenhouse gases impede the escape

of heat from Earth’s surfaceof heat from Earth’s surface

Figure 48.18, Page 880

Global WarmingGlobal Warming

Long-term increase in the temperature Long-term increase in the temperature

of Earth’s lower atmosphereof Earth’s lower atmosphere

Figure 48.19, Page 881

Carbon Dioxide IncreaseCarbon Dioxide Increase

Carbon dioxide levels fluctuate seasonally Carbon dioxide levels fluctuate seasonally

The average level is steadily increasingThe average level is steadily increasing

Burning of fossil fuels and deforestation Burning of fossil fuels and deforestation

are contributing to the increaseare contributing to the increase

1999

1975

domestication of plants, animals 9000 B.C. (about 11,000 years ago)

agriculturally based urban societies

beginning of industrial, scientific revolutions

Human Population GrowthHuman Population Growth

DDT in Food WebsDDT in Food Webs Synthetic pesticide banned in United States Synthetic pesticide banned in United States

since the 1970ssince the 1970s

Birds that are carnivores accumulate DDT Birds that are carnivores accumulate DDT in their tissues, produce brittle egg shellsin their tissues, produce brittle egg shells

DDT in an Estuary (1967) – DDT in an Estuary (1967) – Rachel Carson’s Rachel Carson’s Silent SpringSilent Spring

DDT Residues (ppm wet weight of whole live organism)

Ring-billed gull fledgling (Larus delawarensis)Herring gull (Larus argentatus)Osprey (Pandion haliaetus)Green heron (Butorides virescens)Atlantic needlefish (Strongylira marina)Summer flounder (Paralychthys dentatus)Sheepshead minnow (Cyprinodon variegatus)Hard clam (Mercenaria mercenaria)Marsh grass shoots (Spartina patens)Flying insects (mostly flies)Mud snail (Nassarius obsoletus)Shrimps (composite of several samples)Green alga (Cladophora gracilis)Plankton (mostly zooplankton)Water

75.5 18.5 13.8 3.57 2.07 1.28 0.940.420.33 0.30 0.26 0.16 0.083 0.040 0.00005

Keystone SpeciesKeystone Species

A species that can dictate community A species that can dictate community

structurestructure

Removal of a keystone species can cause Removal of a keystone species can cause

drastic changes in a community; can drastic changes in a community; can

increase or decrease diversity increase or decrease diversity

Exotic SpeciesExotic Species

Species that has left its home range Species that has left its home range

and become established elsewhereand become established elsewhere

Becomes part of its new communityBecomes part of its new community

Can have beneficial, neutral, or harmful Can have beneficial, neutral, or harmful

effects on a communityeffects on a community

Endangered SpeciesEndangered Species

A species that is extremely vulnerable to A species that is extremely vulnerable to

extinctionextinction

Close to 70 percent of endangered Close to 70 percent of endangered

species have been negatively affected by species have been negatively affected by

exotic competitorsexotic competitors

Adaptive Responses to Adaptive Responses to Environmental PressuresEnvironmental Pressures

Prey DefensesPrey Defenses

CamouflageCamouflage

Warning colorationWarning coloration

MimicryMimicry

Parental behaviorsParental behaviors

Feeding strategiesFeeding strategies

Behavioral responsesBehavioral responses

Plant Tropisms and other Plant Tropisms and other ResponsesResponses

Phototropism – plants grow towards a light Phototropism – plants grow towards a light sourcesource

Geo/gravitropism – stems grow away from Geo/gravitropism – stems grow away from gravity; roots grow towards gravitygravity; roots grow towards gravity

Types of Animal BehaviorsTypes of Animal BehaviorsTaxisTaxisReflexesReflexes InstinctsInstinctsLearned behaviorsLearned behaviors

Waggle dance signals food >100 meters from hive

Orientation of straight run shows direction to food

Complex Complex Innate Innate

BehaviorsBehaviors

Biological Clocks and Rhythmic Biological Clocks and Rhythmic BehaviorsBehaviors

Circadian rhythms-internal “biological” Circadian rhythms-internal “biological” clocks clocks

Migration-movement during seasonal Migration-movement during seasonal changeschanges

EstivationEstivationhibernationhibernation

Evolution of Behavioral AdaptationsEvolution of Behavioral Adaptations

Courtship ritualsCourtship ritualsCoevolutionCoevolutionSocial behaviorSocial behaviorJane Goodall- said chimpanzees have Jane Goodall- said chimpanzees have

intricate social and personal personalitiesintricate social and personal personalities

Subordinate member of a wolfpack

CoevolutionCoevolution

Joint evolution of two or more species that Joint evolution of two or more species that exert selection pressure on each other as exert selection pressure on each other as an outcome of close ecological interactionan outcome of close ecological interaction

As snail shells have thickened, claws of As snail shells have thickened, claws of snail-eating crabs have become more snail-eating crabs have become more massivemassive

Predator ResponsesPredator Responses

Any adaptation that protects prey may Any adaptation that protects prey may

select for predators that can overcome select for predators that can overcome

that adaptationthat adaptation

Prey adaptations include stealth, Prey adaptations include stealth,

camouflage, and ways to avoid chemical camouflage, and ways to avoid chemical

repellentsrepellents