Natural Selection, Natural Selection, Adaptations, and NichesAdaptations, and Niches

Essential Targets:Essential Targets:

Define the terms: Natural Selection, Define the terms: Natural Selection, Adaptation, and NicheAdaptation, and Niche

Explain how adaptations benefit an organismExplain how adaptations benefit an organism Identify and describe the three types of Identify and describe the three types of

interactions between organisms in a interactions between organisms in a communitycommunity

What is Natural Selection?What is Natural Selection? Every organism has some Every organism has some

unique unique characteristicscharacteristics that that enable it to live in its enable it to live in its EnvironmentEnvironment

In response to their In response to their environment, species environment, species evolve, or change over timeevolve, or change over time

The changes that make The changes that make organisms better suited to organisms better suited to their environment become their environment become common in that species by a common in that species by a process called process called natural natural selection selection

Charles Darwin 1809-1882

“ “Bummer of a birthmark, Hal.”Bummer of a birthmark, Hal.”

Example of Natural SelectionExample of Natural Selection

One of the first examples of selection in nature was One of the first examples of selection in nature was provided by the peppered moth.provided by the peppered moth.

Up until 1850, the dark form of Up until 1850, the dark form of the peppered moth had been very the peppered moth had been very

rare in England.rare in England.

By 1895, the dark form made up By 1895, the dark form made up 98% of moth populations in some 98% of moth populations in some

industrial areas.industrial areas.

What was the explanation What was the explanation for the increased frequency for the increased frequency

of the dark form in of the dark form in industrial areas?industrial areas?

The hypothesis was that pollution had The hypothesis was that pollution had darkened the trees by killing the darkened the trees by killing the

lichens, making the light phenotype lichens, making the light phenotype more susceptible to bird predation.more susceptible to bird predation.

We can test this We can test this hypothesis by asking hypothesis by asking

what should be what should be happening today since happening today since

pollution has been pollution has been reduced by legislation.reduced by legislation.

What would you predict?What would you predict?

Do the data in this graph support the Do the data in this graph support the pollution/selection hypothesis?pollution/selection hypothesis?

Natural SelectionNatural Selection

Those species that live longer live to Those species that live longer live to reproduce and pass along those characteristics reproduce and pass along those characteristics (traits)(traits)

Natural Selection leads to “?”Natural Selection leads to “?”

The results of natural selection are The results of natural selection are adaptationsadaptations

The behaviors and physical characteristics of The behaviors and physical characteristics of species that allow them to live successfully in species that allow them to live successfully in their environmenttheir environment

Every organism has a variety of adaptations Every organism has a variety of adaptations that are suited to its specific living conditions. that are suited to its specific living conditions. These adaptations create a unique role for the These adaptations create a unique role for the organism in its ecosystem organism in its ecosystem

AdaptationsAdaptations

Adaptation: A physical feature or behavior that allows an organism to survive in its environment

Lynx vs. BobcatLynx vs. Bobcat

Canada Lynx (Canada Lynx (Lynx Lynx lynxlynx

Bobcat (Bobcat (Lynx rufusLynx rufus ) )

Lynx vs. Snowshoe HareLynx vs. Snowshoe Hare

Interaction of OrganismsInteraction of Organisms

Some adaptations involve how organisms Some adaptations involve how organisms interactinteract. .

1.1. CompetitionCompetition

2.2. PredationPredation

3.3. SymbiosisSymbiosis

CompetitionCompetition

CompetitionCompetition - the struggle between organisms to - the struggle between organisms to survive as they attempt to use the same limited survive as they attempt to use the same limited resource.resource.

Swift Fox Coyote Gray Wolf

PredationPredation

PredationPredation - one organism kills and eats another organism. - one organism kills and eats another organism. The organism that does the killing is the The organism that does the killing is the predatorpredator. The . The organism that is killed is the organism that is killed is the preyprey. Predators have adaptations . Predators have adaptations that help them catch and kill their prey. Prey organisms have that help them catch and kill their prey. Prey organisms have adaptations that help them avoid being caught and eaten.adaptations that help them avoid being caught and eaten.

SymbiosisSymbiosis

SymbiosisSymbiosis - a close relationship between two - a close relationship between two species that benefits at least one of the species that benefits at least one of the species.species.

1.1. Mutualism (both species benefit)Mutualism (both species benefit)

2.2. Commensalism (one species benefits. Other is Commensalism (one species benefits. Other is not effected)not effected)

3.3. Parasitism (one species benefits. Other is Parasitism (one species benefits. Other is harmed)harmed)

NicheNiche

An organism’s particular role in its habitat, or An organism’s particular role in its habitat, or how it makes its living, is called its how it makes its living, is called its nicheniche

A niche includes the type of food the organism A niche includes the type of food the organism eats, how it obtains this food, which other eats, how it obtains this food, which other species use it as food, when and how the species use it as food, when and how the organism reproduces, and the physical organism reproduces, and the physical conditions it requires to survive.conditions it requires to survive.

Understanding an ecological nicheUnderstanding an ecological niche

The idea of an ecological The idea of an ecological niche is very simple. You just niche is very simple. You just need to know where the need to know where the animal or plant lives and animal or plant lives and what it does.what it does.

Oak treesOak trees live in oak live in oak woodlands. The oak woodland woodlands. The oak woodland is the habitat. So if you were is the habitat. So if you were writing a letter to an oak tree writing a letter to an oak tree you would address the letter to:you would address the letter to:

Mr. Deciduous Oak Tree,Mr. Deciduous Oak Tree,The Oak Forest,The Oak Forest,Maine, USA.Maine, USA.

Understanding an ecological nicheUnderstanding an ecological niche What do oak trees do? If you can answer that What do oak trees do? If you can answer that

question you know the oak trees "profession" question you know the oak trees "profession" or its ecological niche. Perhaps you think that or its ecological niche. Perhaps you think that oak trees just stand there looking pretty and oak trees just stand there looking pretty and not doing vey much, but think about it.not doing vey much, but think about it.

1.1. absorb sunlight by photosynthesis; absorb sunlight by photosynthesis; 2.2. absorb water and mineral salts from the soil; absorb water and mineral salts from the soil; 3.3. provide shelter for many animals and other provide shelter for many animals and other

plants; plants; 4.4. act as a support for creeping plants; act as a support for creeping plants; 5.5. serve as a source of food for animals; serve as a source of food for animals; 6.6. cover the ground with their dead leaves in the cover the ground with their dead leaves in the

autumn.autumn. These six things are the "profession" or These six things are the "profession" or

ecological niche of the oak tree; you can think ecological niche of the oak tree; you can think of it as being a kind of job description. If the of it as being a kind of job description. If the oak trees were cut down or destroyed by fire oak trees were cut down or destroyed by fire or storms they would no longer be doing their or storms they would no longer be doing their job and this would have a disastrous effect on job and this would have a disastrous effect on all the other organisms living in the same all the other organisms living in the same habitat.habitat.

Understanding an ecological nicheUnderstanding an ecological niche

Now you get to try:Now you get to try:

Where does this species live?

What does this species do?

Understanding an ecological nicheUnderstanding an ecological niche

Now you get to try:Now you get to try:

Where does this species live?

What does this species do?

Questions?Questions?

Essential Targets:Essential Targets:

Define the terms: Natural Selection, Define the terms: Natural Selection, Adaptation, and NicheAdaptation, and Niche

Explain how adaptations benefit an organismExplain how adaptations benefit an organism Identify and describe the three types of Identify and describe the three types of

interactions between organisms in a interactions between organisms in a communitycommunity