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AP Bio Exam Review Ecology Unit

AP Bio Exam Review Ecology Unit

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AP Bio Exam Review Ecology Unit. Ecology : the scientific study of the interactions between organisms and the environment. The ecological study of species involves biotic and abiotic influences. Biotic = living (organisms) Abiotic = nonliving (temp, water, salinity, sunlight, soil). - PowerPoint PPT Presentation

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Page 1: AP Bio Exam Review Ecology Unit

AP Bio Exam ReviewEcology Unit

Page 2: AP Bio Exam Review Ecology Unit

Ecology: the scientific study of the interactions between organisms and the environment

• The ecological study of species involves biotic and abiotic influences.– Biotic = living (organisms)– Abiotic = nonliving (temp, water, salinity, sunlight,

soil)

Page 3: AP Bio Exam Review Ecology Unit

Heirarchy

• Organisms• Population: group of individuals of same

species living in a particular geographic area• Community: all the organisms of all the

species that inhabit a particular area• Ecosystem: all the abiotic factors +

community of species in a certain area• Biosphere: global ecosystem

Page 4: AP Bio Exam Review Ecology Unit

Learning is experience-based modification of behavior

• Learning ranges from simple behavioral changes to complex problem solving

– Learning: a change in behavior resulting from experience

– Social learning involves changes in behavior that result from the observation and imitation of others

Vervet alarm call

Page 5: AP Bio Exam Review Ecology Unit

Innate behavior is developmentally fixed• Unlearned behavior• Environmental indifference - performed the

same way by all members of a species

• Fixed action patterns (FAPs): innate behaviors that exhibit unchangeable sequences; carried to completion

• Triggered by sign stimulus

• Ensures that activities essential to survival are performed correctly without practice

Page 6: AP Bio Exam Review Ecology Unit

• Kinesis: simple change in activity or turning rate in response to a stimulus

• Taxis: automatic movement, oriented movement +/- from stimulus; i.e. Phototaxis, chemotaxis, and geotaxis.

Directed Movements

Kinesis increases the chance that a sow bug will encounter and stayin a moist environment.

Positive rheotaxis keeps trout facing into the current, the directionfrom which most food comes.

Page 7: AP Bio Exam Review Ecology Unit

Types of Learning1. Habituation: loss of responsiveness to

stimuli that convey little or no information– Simple form of learning

2. Imprinting: learning + innate components– Limited to sensitive period in

life, generally irreversible– ie. Lorenz’ imprinting in greylag

geese

Page 8: AP Bio Exam Review Ecology Unit

Types of Learning

3. Associative learning: ability to associate one stimulus with another– Also called classical conditioning– Fruit fly (drosophila): trained to respond to odor +

shock

Page 9: AP Bio Exam Review Ecology Unit

Types of Learning

Operant conditioning: another type of associative learning– Trial-and-error learning– Associate its own behavior with reward or

punishment

Page 10: AP Bio Exam Review Ecology Unit

Types of Learning

4. Cognition: the ability of an animal’s nervous system to:– Perceive, store, process, and use information

gathered by sensory receptors– Problem-solving behavior relies on cognition

Page 11: AP Bio Exam Review Ecology Unit

Territorial Behavior

• Territorial behavior parcels space and resources– Animals exhibiting this behavior mark and defend their

territories

Page 12: AP Bio Exam Review Ecology Unit

Clumped. For many animals, such as these wolves, living in groups increases the effectiveness of hunting, spreads the work of protecting and caring for young, and helps exclude other individuals from their territory.

Uniform. Birds nesting on small islands, such as these king penguins on South Georgia Island in the South Atlantic Ocean, often exhibit uniform spacing, maintained by aggressive interactions between neighbors.

Random. Dandelions grow from windblown seeds that land at random and later germinate.

Patterns of Dispersal:

1. Clumped – most common; near required resource

2. Uniform – usually antagonistic interactions

3. Random – not common in nature

Page 13: AP Bio Exam Review Ecology Unit

• Additions occur through birth, and subtractions occur through death.

• A life table is an age-specific summary of the survival pattern of a population.

• A graphical way of representing the data is a survivorship curve.– This is a plot of the number of individuals in a cohort

still alive at each age.

Demography: the study of vital statistics that affect population size

Page 14: AP Bio Exam Review Ecology Unit

Survivorship Curves:•Type I curve: low death rate early in life (humans)

•Type II curve: constant death rate over lifespan (squirrels)

•Type III curve: high death rate early in life (oysters)

Page 15: AP Bio Exam Review Ecology Unit

• Zero population growth: B = D• Exponential population growth: ideal

conditions, population grows rapidly

Number of generations

Popu

latio

n si

ze (N

)2,000

= 1.0N

1,000

1,500

500

0151050

dNdt

= 0.5NdNdt

Page 16: AP Bio Exam Review Ecology Unit

• Unlimited resources are rare• Logistic model: incorporates carrying capacity (K)

– K = maximum stable population which can be sustained by environment

• dN/dt = rmax((K-N)/K)• S-shaped curve

Page 17: AP Bio Exam Review Ecology Unit

• K-selection: pop. close to carrying capacity• r-selection: maximize reproductive success

K-selection r-selectionLive around K Exponential growth

High prenatal care Little or no care

Low birth numbers High birth numbers

Good survival of young Poor survival of young

Density-dependent Density independent

ie. Humans ie. cockroaches

Page 18: AP Bio Exam Review Ecology Unit

Factors that limit population growth:

• Density-Dependent factors: population matters– i.e. Predation, disease, competition, territoriality,

waste accumulation• Density-Independent factors: population not a factor

– i.e. Natural disasters: fire, flood, weather

Page 19: AP Bio Exam Review Ecology Unit

Age-Structure Diagrams

Page 20: AP Bio Exam Review Ecology Unit

Interspecific interactions• Can be positive (+), negative (-) or neutral (0)• Includes competition, predation, and symbiosis

Page 21: AP Bio Exam Review Ecology Unit

• Interspecific competition for resources can occur when resources are in short supply

• Species interaction is -/-• Competitive exclusion principle: Two species

which cannot coexist in a community if their niches are identical.– The one with the slight reproductive advantage will

eliminate the other

Page 22: AP Bio Exam Review Ecology Unit

Ecological niche: the sum total of an organism’s use of abiotic/biotic resources in

the environment• Fundamental niche = niche potentially occupied

by the species• Realized niche = portion of fundamental niche

the species actually occupies

Chthamalusfundamental niche

High tide

Low tideOcean

Chthamalusrealized niche

High tide

Low tideOcean

Balanusrealized niche

ChthamalusBalanus

Page 23: AP Bio Exam Review Ecology Unit

Predation (+/-)Defensive adaptations include:

– Cryptic coloration – camouflaged by coloring– Aposematic or warning coloration – bright color of

poisonous animals– Batesian mimicry – harmless species mimic color

of harmful species– Mullerian mimicry – 2 bad-tasting species

resemble each other; both to be avoided– Herbivory – plants avoid this by chemical toxins,

spines, & thorns

Page 24: AP Bio Exam Review Ecology Unit

Community StructureSpecies diversity = species richness (the number

of different species they contain), and the relative abundance of each species.

• Dominant species: has the highest biomass or is the most abundant in the community

• Keystone species: exert control on community structure by their important ecological niches– Ex: loss of sea otter increase sea urchins,

destruction of kelp forests

Page 25: AP Bio Exam Review Ecology Unit

Disturbances influences species diversity and composition

• A disturbance changes a community by removing organisms or changing resource availability (fire, drought, flood, storm, human activity)

• Ecological succession: transitions in species composition in a certain area over ecological time

Page 26: AP Bio Exam Review Ecology Unit

Primary Succession• Plants & animals invade where soil

has not yet formed– Ex. colonization of volcanic island or

glacier

Page 27: AP Bio Exam Review Ecology Unit

Secondary Succession• Occurs when existing community is cleared by

a disturbance that leaves soil intact– Ex. abandoned farm, forest fire

Soon after fire. As this photo taken soon after the fire shows, the burn left a patchy landscape. Note the unburned trees in the distance.

One year after fire. This photo of the same general area taken the following year indicates how rapidly the com-munity began to recover. A variety of herbaceous plants, different from those in the former forest, cover the ground.

Page 28: AP Bio Exam Review Ecology Unit

Ecosystems

Ecosystem = sum of all the organisms living within its boundaries (biotic community) + abiotic factors with which they interact

Involves two unique processes:1. Energy flow2. Chemical cycling

Page 29: AP Bio Exam Review Ecology Unit

Microorganismsand other

detritivores

Tertiaryconsumers

Secondaryconsumers

Detritus Primary consumers

Sun

Primary producers

Heat

Key

Chemical cyclingEnergy flow

Page 30: AP Bio Exam Review Ecology Unit

Trophic Structures

• The trophic structure of a community is determined by the feeding relationships between organisms.

• Trophic levels = links in the trophic structure

• The transfer of food energy from plants herbivores carnivores decomposers is called the food chain.

Page 31: AP Bio Exam Review Ecology Unit

• Two or more food chains linked together are called food webs.

• A given species may weave into the web at more than one trophic level.

Page 32: AP Bio Exam Review Ecology Unit
Page 33: AP Bio Exam Review Ecology Unit

Primary Production

• Total primary production is known as gross primary production (GPP).– This is the amount of light energy that is

converted into chemical energy.• The net primary production (NPP) is equal to

gross primary production minus the energy used by the primary producers for respiration (R):– NPP = GPP – R

• NPP = storage of chemical energy available to consumers in an ecosystem

Page 34: AP Bio Exam Review Ecology Unit

Open oceanContinental shelf

Upwelling zonesExtreme desert, rock, sand, ice

Swamp and marshLake and stream

Desert and semidesert scrubTropical rain forest

Temperate deciduous forestTemperate evergreen forest

Tropical seasonal forest

SavannaCultivated land

EstuaryAlgal beds and reefs

Boreal forest (taiga)Temperate grassland

Woodland and shrublandTundra

0.40.4

1.01.31.51.61.71.82.42.72.93.33.54.7

0.30.10.1

5.265.0

Freshwater (on continents)TerrestrialMarine

Key Percentage of Earth’ssurface area

Average net primaryproduction (g/m2/yr)

6050403020100 2,5002,0001,5001,0005000Percentage of Earth’s netprimary production

2520151050

125

2,500

3601,500

5003.090

900600

800

2,200

600

250

1,6001,2001,300

2,000

700140

0.3

7.99.19.6

5.43.5

0.67.1

4.93.8

2.3

24.45.6

1.20.9

0.10.040.9

22

Net primary production of different ecosystems

Page 35: AP Bio Exam Review Ecology Unit

• Primary production affected by:– Light availability (↑ depth, ↓ photosynthesis)– Nutrient availability (N, P in marine env.)

• Key factors controlling primary production:– Temperature & moisture

• A nutrient-rich lake that supports algae growth is eutrophic.

Page 36: AP Bio Exam Review Ecology Unit

Energy transfer between trophic levels is typically only 10% efficient

Growth (new biomass)

CellularrespirationFeces 100 J

33 J

67 J

200 J

Plant materialeaten by caterpillar

• Production efficiency: only fraction of E stored in food

• Energy used in respiration is lost as heat

• Energy flows (not cycle!) within ecosystems

Page 37: AP Bio Exam Review Ecology Unit

1,000,000 J of sunlight

10,000 J

1,000 J

100 J

10 JTertiaryconsumers

Secondaryconsumers

Primaryconsumers

Primaryproducers

10% transfer of energy from one

level to next

Page 38: AP Bio Exam Review Ecology Unit

Pyramids of energy or biomass or numbers gives insight to food chains

Pyramid of Numbers

Pyramid of Biomass

• Loss of energy limits # of top-level carnivores

• Most food webs only have 4 or 5 trophic levels

Page 39: AP Bio Exam Review Ecology Unit

Matter Cycles in Ecosystem

• Biogeochemical cycles: nutrient cycles that contain both biotic and abiotic components

• organic inorganic parts of an ecosystem• Nutrient Cycles: water, carbon, nitrogen,

phosphprus

Page 40: AP Bio Exam Review Ecology Unit

Cellularrespiration

Burning offossil fuelsand wood

Carbon compoundsin water

Photosynthesis

Primaryconsumers

Higher-levelconsumers

Detritus

Decomposition

CO2 in atmosphere

Carbon Cycle

• CO2 removed by photosynthesis, added by burning fossil fuels

Page 41: AP Bio Exam Review Ecology Unit

Assimilation

N2 in atmosphere

Decomposers Nitrifyingbacteria

Nitrifyingbacteria

Nitrogen-fixingsoil bacteria

Denitrifyingbacteria

NitrificationAmmonification

Nitrogen-fixingbacteria in rootnodules of legumes

NO3–

NO2–NH4

+NH3

Nitrogen Cycle• Nitrogen fixation:

– N2 plants by bacteria

• Nitrification:– ammonium nitrite

nitrate– Absorbed by plants

• Denitrification:– Release N to atmosphere

Page 42: AP Bio Exam Review Ecology Unit

• Acid precipitation: rain, snow, or fog with a pH less than 5.6

• Caused by burning of wood & fossil fuels– Sulfur oxides and nitrogen oxides released– React with water in the atmosphere to produce

sulfuric and nitric acids• These acids fall back to earth as acid

precipitation, and can damage ecosystems greatly.

• The acids can kill plants, and can kill aquatic organisms by changing the pH of the soil and water.

Acid Precipitation

Page 43: AP Bio Exam Review Ecology Unit

• Toxins become more concentrated in successive trophic levels of a food web

• Toxins can’t be broken down & magnify in concentration up the food chain

• Problem: mercury in fish

Biological Magnification

Zooplankton0.123 ppm

Phytoplankton0.025 ppm

Lake trout4.83 ppm

Smelt1.04 ppm

Herringgull eggs124 ppm

Con

cent

ratio

n of

PC

Bs

Page 44: AP Bio Exam Review Ecology Unit

Greenhouse Effect

– Greenhouse Effect: absorption of heat the Earth experiences due to certain greenhouse gases

• CO2 and water vapor causes the Earth to retain some of the infrared radiation from the sun that would ordinarily escape the atmosphere

– The Earth needs this heat, but too much could be disastrous.

Page 45: AP Bio Exam Review Ecology Unit

Rising atmospheric CO2

– Since the Industrial Revolution, the concentration of CO2 in the atmosphere has increased greatly as a result of burning fossil fuels.

Page 46: AP Bio Exam Review Ecology Unit

Global Warming

• Scientists continue to construct models to predict how increasing levels of CO2 in the atmosphere will affect Earth.

• Several studies predict a doubling of CO2 in the atmosphere will cause a 2º C increase in the average temperature of Earth.

• Rising temperatures could cause polar ice cap melting, which could flood coastal areas.

– It is important that humans attempt to stabilize their use of fossil fuels.

Page 47: AP Bio Exam Review Ecology Unit

Human activities are depleting the atmospheric ozone

• Life on earth is protected from the damaging affects of ultraviolet radiation (UV) by a layer of O3,or ozone.

• Chlorine-containing compounds erode the ozone layer

Page 48: AP Bio Exam Review Ecology Unit

The four major threats to biodiversity:

1. Habitat destruction– Human alteration of habitat is the single

greatest cause of habitat destruction.2. Introduced species: invasive/nonnative/exotic

species3. Overexploitation: harvest wild plants/animals4. Food chain disruption: extinction of keystone

species