Environmental ScienceEnvironmental ScienceLiving Things in Living Things in

EcosystemsEcosystems

Chapter 2Chapter 2

Notes #3Notes #3

10/09/0810/09/08

LaVigne

2.1 Ecosystems2.1 Ecosystems

Biotic/Abiotic interactionsBiotic/Abiotic interactions

► Limiting FactorsLimiting Factors Anything that controls a populationAnything that controls a population RainRain FoodFood FF ireire ????????

► Carrying CapacityCarrying Capacity # of a species that can be kept in an ecosystem# of a species that can be kept in an ecosystem Most populations vary above and below the Most populations vary above and below the

carrying capacity but stay near it.carrying capacity but stay near it.

2.2 2.2 How species interact with each How species interact with each

other other ►5 Major Interactions Among Biotic 5 Major Interactions Among Biotic

Factors in an EcosystemFactors in an Ecosystem PredationPredation CompetitionCompetition ParasitismParasitism MutualismMutualism CommensalismCommensalism

5.3 Adapting to the 5.3 Adapting to the EnvironmentEnvironment

► Charles DarwinCharles Darwin an English naturalist (1859) an English naturalist (1859) Sailed on the HMS Beagle 1600’sSailed on the HMS Beagle 1600’s King wanted inventory of his territoryKing wanted inventory of his territory Sailed to all British coloniesSailed to all British colonies Saw many different types of plants & animalsSaw many different types of plants & animals

►Darwin’s ObservationsDarwin’s Observations Saw finches on the Galapagos IslandsSaw finches on the Galapagos Islands Noticed that each island had finches that all fit the Noticed that each island had finches that all fit the

food available on that islandfood available on that island How can different beaks be on the same type of How can different beaks be on the same type of

finch?finch?

5.3 Adapting to the 5.3 Adapting to the EnvironmentEnvironment

► Darwin tried to make sense of his Darwin tried to make sense of his observations observations He proposed that the environment exerts a He proposed that the environment exerts a

strong influence over which individuals strong influence over which individuals have offspringhave offspring

►Natural SelectionNatural Selection – some individuals – some individuals because of certain traits are more likely to because of certain traits are more likely to survive & have offspring than otherssurvive & have offspring than others (there’s unequal survival/reproduction that results (there’s unequal survival/reproduction that results

from the presence or absence of particular traits)from the presence or absence of particular traits)

5.3 Adapting to the 5.3 Adapting to the EnvironmentEnvironment

►over many generations characteristics over many generations characteristics change- change- evolutionevolution

►adaptationadaptation – inherited trait increases – inherited trait increases an organisms chance of survival & an organisms chance of survival & reproduction in a certain environmentreproduction in a certain environment

►BearsBears Similar animals in different environments Similar animals in different environments

have different adaptationshave different adaptations Polar bear- white, big feet, large sizePolar bear- white, big feet, large size Black bear- black, small feet, medium sizeBlack bear- black, small feet, medium size

►Each has gone through selection over a long Each has gone through selection over a long time in their environmentstime in their environments

5.3 Adapting to the Environment5.3 Adapting to the Environment

5.3 Adapting to the 5.3 Adapting to the EnvironmentEnvironment

►species can evolve in response to each species can evolve in response to each other = other = coevolutioncoevolution Ex.Ex. A plant starts creating a chemical to A plant starts creating a chemical to

prevent animals from eating it and then prevent animals from eating it and then the animal gains the ability to detox itself the animal gains the ability to detox itself from the chemicalfrom the chemical►Ex. Ex. Cabbage butterfly caterpillars can break Cabbage butterfly caterpillars can break

down mustard oils, when many other animals down mustard oils, when many other animals cannot – so it can feed on plants that other cannot – so it can feed on plants that other animals cannotanimals cannot

►extinctionextinction – irreversible disappearance – irreversible disappearance of a population or speciesof a population or species

5.3 Adapting to the 5.3 Adapting to the EnvironmentEnvironment

►Theory of Evolution Based on Natural Theory of Evolution Based on Natural SelectionSelection

►OverproductionOverproduction►VariationVariation►Reproduction (passing on variation)Reproduction (passing on variation)►Some variations are helpfulSome variations are helpful►Helpful variations make up more and Helpful variations make up more and

more of the population as time goes bymore of the population as time goes by

5.3 Adapting to the Environment5.3 Adapting to the Environment► AntibioticsAntibiotics

Dr. prescribes antibiotics and says “take these until they are all Dr. prescribes antibiotics and says “take these until they are all gone in 10 days”gone in 10 days”

After 5 days you feel betterAfter 5 days you feel better Should you stop taking the pills?Should you stop taking the pills?

► If you stop you may be helping select a stronger If you stop you may be helping select a stronger version of your illness!!!!version of your illness!!!! Why?Why? Antibiotics are prescribed to help you by killing bacteria.Antibiotics are prescribed to help you by killing bacteria. After 5 days the weaker bacteria are dead, there are few left, After 5 days the weaker bacteria are dead, there are few left,

and you feel better.and you feel better.► THE STRONG BACTERIA ARE ALIVE!THE STRONG BACTERIA ARE ALIVE!► By not killing off all the bacteria you are helping to By not killing off all the bacteria you are helping to

breed a stronger strain!breed a stronger strain!

AssignmentsAssignments

►Complete the 2.2 Section review (#1-4)Complete the 2.2 Section review (#1-4) Definition of each interaction + ex on the Definition of each interaction + ex on the

backback Hand it inHand it in Complete and hand in the video worksheet Complete and hand in the video worksheet

packet from yesterday.packet from yesterday.

►Complete the 2.3 section review (p 46, Complete the 2.3 section review (p 46, 1-4)1-4)

►Complete the Transparency ws #3Complete the Transparency ws #3