Survival of the Fittest - PowerPoint Presentation

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Survival of the Fittest

Adaptation, Mutation, and Finches?Slide2
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Natural Selection

Natural selection means that traits that offer an advantage will most likely be passed on to offspring; individuals with those traits have a better chance of surviving. Slide4

Lemurs of MadagascarSlide5

Amazonian FrogsSlide6

Bred Pigeons came from a single original species

Humans select traits for dogs, pigeons and other animals when they breed them.

Who

selects the traits for wild plans & animals?Slide7

INDIVIDUALS THAT HAVE TRAITS THAT ARE BEST ADAPTED FOR THE CURRENT ENVIRONMENT ARE THE ONES THAT SURVIVE TO BREED AND PASS ON THEIR GENES TO THE NEXT GENERATION.

NOBODY!!

Organisms not possessing the beneficial traits either die or don’t have as many offspring.

There is no agent involved in natural selection.

Natural selection is a process of elimination

Natural Selection is

Survival

of the

FittestSlide8

Survival of the fittest?

The individuals that survive are not always the strongest, fastest, or smartest. Therefore, "survival of the fittest" may not be the best way to describe what natural selection really is as it applies to

evolution.

Darwin

meant "fittest" to mean the one best suited for the immediate environment. This is the basis of the idea of natural selection.

The

individual of the population only needs to have the most favorable traits to survive in the environment. It should follow that individuals who have the favorable adaptations will live long enough to pass down those genes to their offspring.

Individuals

lacking the favorable traits, in other words the "unfit", will most likely not live long enough to pass down the unfavorable traits and eventually those traits will be bred out of the population.

The

unfavorable traits may take many generations to decline in numbers and even longer to disappear completely from the gene pool.

This

is evident in humans with the genes of fatal diseases are still in the gene pool even though they are unfavorable for the survival of the species.Slide9

Natural Selection is a mixture of both Chance and

necessity

Natural Selection is not goal directed. It does not have a long term goal.Slide10

What

are pressures that act on

a population?

Competition for food

Competition for a mate

Changes in the environment

Predators

ParasitesSlide11

Examples of selection pressures...

Predators -

variants with adaptations allowing them to escape predators have more offspring

e.g

. speed, defensive weapons, camouflage,

mimicry

Prey/Food

- variants with adaptations allowing them to obtain food have more offspring

e.g

. Speed, senses for finding prey/food, weapons for killing prey or obtaining food, camouflage for

stealth

Climate - those who can survive new climate best have more kidse.g. ice age, change in climate due to migration

.

Mates

- variants with adaptations allowing them to attract a mate to have offspring

- e.g. strong, attractive, good providerSlide12

Mechanism for change in a population of organisms

Animals who have greater

fitness

survive in environment and live to reproduce

Random changes (

mutations) can lead to greater or less fitness Adaptations allow an organism to survive better in their environmentSlide13

Natural Selection vs. Selective Breeding

Natural Selection

Selective Breeding

Process by which organisms that are

most suited

to their environment

survive and reproduce most successfully.

Method of breeding that allows only those organisms with

desired characteristics

to

produce the next generation.Slide14

*Follow along with your video note sheet!Slide15

Let’s Review

Do you remember these guys?Slide16

The adaptation of a population in response to pollution.

“Industrial

Melanism

”- darkness- of the skin, feathers, or fur. Acquired by a population of animals living in an industrial region where the environment is soot-darkened. Slide17

Example: Peppered Moths

Manchester, England from 1845 to 1890.

Before the industrial revolution, the trunks of the trees in the forest around Manchester were light grayish-green due to the presence of lichens.Slide18

Most of the peppered moths in the area were light colored with dark spots.

As the industrial revolution progressed, the tree trunks became covered with soot and turned dark.

Over a period of 45 years, the dark variety of the peppered moth became more common.Slide19

Can you see the moths?Slide20

Natural

Selection

Summary:

Environmental Influence due to organism adaptation.

Mouth parts

ex: beaks, teeth

External color

ex: fur,

scales, feathers

BehaviorSlide21

Galapagos Islands

1850’s: Charles Darwin described how organisms might change over time.

Theory of Evolution

5 years of observations on the islands.

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The Galapagos Island

The smallest, lowest islands were hot, dry, and nearly barren-Hood Island-sparse vegetation

The higher islands had greater rainfall and a different assortment of plants and animals-Isabela- Island had rich vegetation

.Slide23

Galapagos

FinchesSlide24

The Galapagos Island

Darwin was fascinated in particular by the land tortoises and marine iguanas in the Galápagos.

Giant tortoises varied in predictable ways from one island to another.

The shape of a tortoise's shell could be used to identify which island a particular tortoise inhabited. Slide25
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Animals found in the Galapagos

Land Tortoises

Darwin Finches

Blue-Footed Booby

Marine IguanasSlide27

AnimalsSlide28

The Journey Home

Darwin Observed that characteristics of many plants and animals vary greatly among the islands

Hypothesis:

Separate species may have arose from an original ancestorSlide29

Selective

breeding

Summary:

Human Influence on characteristics and behavior

.

Domestic Animals

Ex: Chickens, Dogs, Cows

Plants:

Ex: Corn,

Brasilica

, Fruit hybridsSlide30

Domestic Animals

Various animals that have been tamed and made fit for a human environment.Slide31

Bull Terrier

Basset Hound

Boxer

A shorter face means a host of problems. The modern Boxer not only has a shorter face but the muzzle is slightly upturned. The boxer – like all

bracecyphalic

dogs – has difficulty controlling its temperature in hot weather, the inability to shed heat places limits on physical performance. It also has one of the highest cancer rates.

Pug

The Pug is another extreme brachycephalic breed and it has all the problems associated with that trait – high blood pressure, heart problems, low oxygenation, difficulty breathing, tendency to overheat, dentition problems, and skin fold dermatitis. The highly desirable double-curl tail is actually a genetic defect, in more serious forms it leads to paralysis.Slide32
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Hybrid Fruits

Nectarcots

Pluots

How many types of apples are there?Slide37