Populations and Populations and CommunitiesCommunities

Living Things and the Living Things and the EnvironmentEnvironment

A little vocab…A little vocab… EcologyEcology - the study of - the study of

how organisms interact how organisms interact with their environmentwith their environment

OrganismOrganism - a living - a living thingthing

HabitatHabitat - the specific - the specific environment that environment that provides the things an provides the things an organism needs to live, organism needs to live, grow, and reproducegrow, and reproduce

Living or Nonliving?Living or Nonliving?

Biotic FactorBiotic Factor - living parts of a - living parts of a habitathabitat

– ExamplesExamples - flowers, worm, frog - flowers, worm, frog

Abiotic FactorAbiotic Factor - nonliving part of - nonliving part of a habitata habitat

– ExamplesExamples - water, sunlight, oxygen - water, sunlight, oxygen

The Line-UpThe Line-Up SpeciesSpecies - group of organisms - group of organisms

that mate and reproducethat mate and reproduce

PopulationPopulation - all members of - all members of oneone species in a particular species in a particular areaarea

CommunityCommunity - all - all differentdifferent populations that live in an populations that live in an areaarea

EcosystemEcosystem - a community - a community including its surrounding including its surrounding environment (abiotic factors)environment (abiotic factors)

Populations and Populations and CommunitiesCommunities

Studying PopulationsStudying Populations

Types of ObservationsTypes of Observations

Direct ObservationDirect Observation - counting all - counting all individuals by onesindividuals by ones

Indirect ObservationIndirect Observation - counting the - counting the “signs” of an individual“signs” of an individual

Methods of StudyMethods of Study SamplingSampling - taking an - taking an

estimate of a type of estimate of a type of organism in an areaorganism in an area

Mark-and-Mark-and-Recapture StudiesRecapture Studies - catch an organism, - catch an organism, mark it, then releasemark it, then release

Population FluctuationPopulation Fluctuation Birth RateBirth Rate - # of births in a population - # of births in a population

during a specific timeduring a specific time

Death RateDeath Rate - # of deaths in a population - # of deaths in a population during a specific timeduring a specific time

If birth rate is > than death rate, then If birth rate is > than death rate, then population is ____________population is ____________

If birth rate is < than death rate, then If birth rate is < than death rate, then population is ____________population is ____________

Population FluctuationPopulation Fluctuation

ImmigrationImmigration - organisms moving - organisms moving intointo a a populationpopulation

EmigrationEmigration - organisms moving - organisms moving outout of a of a populationpopulation

Population Growth Equation:Population Growth Equation:

(B - D) + (I - E) = N(B - D) + (I - E) = N

*If N is a positive #, the population is increasing*If N is a positive #, the population is increasing

Population FluctuationPopulation Fluctuation

Population DensityPopulation Density - # of - # of individuals in a specific areaindividuals in a specific area

Population Density Equation:Population Density Equation:

# individuals# individuals

Unit areaUnit area

Population FactorsPopulation Factors Limiting FactorLimiting Factor - an environmental factor - an environmental factor

that causes a population to decreasethat causes a population to decrease– Examples:Examples: food and water, space and weather food and water, space and weather

Carrying Capacity (K)Carrying Capacity (K) - the largest - the largest population that an area can carrypopulation that an area can carry

Populations and Populations and CommunitiesCommunities

Interactions Among Living Interactions Among Living ThingsThings

The TheoryThe Theory Natural SelectionNatural Selection – –

individuals who have individuals who have the best characteristics the best characteristics are more likely to are more likely to survive and produce survive and produce offspringoffspring

– Charles DarwinCharles Darwin – (1809 – (1809 – 1882) father of – 1882) father of evolutionary biologyevolutionary biology

A Place in the WorldA Place in the World AdaptationsAdaptations – a physical – a physical

characteristic that helps an organism characteristic that helps an organism live in an area live in an area – Example:Example: cacti in the desert cacti in the desert

NicheNiche – the role of an organism in its – the role of an organism in its habitat, or how it makes its livinghabitat, or how it makes its living– type of food I eattype of food I eat– Who else eats youWho else eats you– Whether you need to surviveWhether you need to survive

The FightThe Fight

CompetitionCompetition – the struggle (fight) – the struggle (fight) between two organism to get the between two organism to get the same thingsame thing

Let’s Eat!Let’s Eat! PredationPredation – when one organism kills – when one organism kills

another for foodanother for food

– PredatorPredator – dominant organism – dominant organismPredator AdaptationsPredator Adaptations – help them catch – help them catch

and kill their preyand kill their prey

– PreyPrey – inferior organism – inferior organismPrey Defense StrategiesPrey Defense Strategies – certain – certain

adaptations to prevent being killed by adaptations to prevent being killed by predatorspredators

– Skunk, poison ivy, porcupinesSkunk, poison ivy, porcupines

RelationshipsRelationships MutualismMutualism – both species benefit – both species benefit

– ExampleExample – hippo and bird – hippo and bird

CommensalismCommensalism – one species benefits – one species benefits and the other is neither helped nor and the other is neither helped nor harmedharmed– ExampleExample – clown fish and sea anemone – clown fish and sea anemone

ParasitismParasitism – one species is benefited and – one species is benefited and the other is harmed. Doesn’t kill because the other is harmed. Doesn’t kill because it needs the host to liveit needs the host to live– ExampleExample – head lice, ringworm, tape worm, – head lice, ringworm, tape worm,

ticksticks

RelationshipRelationship Species OneSpecies One Species TwoSpecies Two

MutualismMutualism ++ ++

CommensalismCommensalism ++ OO

ParasitismParasitism ++ --

Populations and Populations and CommunitiesCommunities

Changes in CommunitiesChanges in Communities

Primary SuccessionPrimary Succession Where no soil or organisms existWhere no soil or organisms exist

– Example: rocks after volcano erupts or Example: rocks after volcano erupts or glaciersglaciers

Pioneer SpeciesPioneer Species – the very first – the very first organisms that inhabit an areaorganisms that inhabit an area– How do they get there?How do they get there?

wind, water, other organisms carry themwind, water, other organisms carry them

– What are they?What are they?Lichens and mossLichens and moss

Secondary SuccessionSecondary Succession

A series of changes in an area where A series of changes in an area where the ecosystem has been disturbed, the ecosystem has been disturbed, but the soil and organisms still existbut the soil and organisms still exist– Example – tornadoes, hurricanes, fires, Example – tornadoes, hurricanes, fires,

logging, and farminglogging, and farming– Faster rate of successionFaster rate of succession

Succession DiagramSuccession Diagram