Theory of Evolution:Change in living organisms over many successive

generations.

Adaptations :inherited characteristics that increases an organisms chance of survival and opportunity to reproduce in it’s niche.

Niche: the specific area where an organism inhabits and its role in that specific area

Founded the theory of natural selection and author of the book “Origin of Species”.

“It is not the strongest of the species that survives,

nor the most intelligent that survives. It is the one that is the most adaptable to

change.” -Charles Darwin, Origin of Species

Overproduction Variation

Natural Selection(struggle for survival)

Reproductive Advantage

Populations tend to produce more offspring than are needed to replace the parents. Natural populations normally maintain constant numbers. There must therefore be a certain death rate.

Individuals in a population vary in their phenotype and therefore, their genotype.

Factors in the environment will determine which traits are favorable or unfavorable. Some traits increase a chance for survival and others do not. Biotic factors: amount of food, presence of

predatorsAbiotic factors: temperature, amount of water,

territory

The variations (both favorable and unfavorable) are passed on to offspring. Each new generation will contain proportionally more descendents from individuals with favorable traits (“the fittest”) than those with unfavorable.

Favorable trait = adaptation

1. Natural selection involves organisms trying to adapt. False

2. Natural selection acts for the good of the species. False

3. Natural selection produces organisms perfectly suited to their environments.

False

4. The fittest organisms in a population are those that are strongest, healthiest, fastest, and/or largest.

False

5. Individuals with favorable traits tend to produce more offspring than those with unfavorable traits. Therefore, over time, favorable traits become more common within a population found in a particular environment.

True

6. The environment determines which traits are favorable and unfavorable

True

7. The only thing random about natural selection is the rate and type of mutations , not the “selection” process.

True

8. Natural selection is one mechanism of evolution. True

Mutations!

1.Mutations are random: Mutations can be beneficial, neutral, or harmful for the organism, but mutations do not “try” to supply what the organism “needs.”

2.Not all mutations matter to evolution: • Somatic mutations occur in non-

reproductive cells and won’t be passed onto offspring.

• The mutation must be inheritable.

In order to see a change in a population, natural selection must take place over multiple generations.

If the environment changes, the favorable adaptation may no longer be favorable.

Geographic Isolation: 1. A population is separated by a physical barrier

into different environments (ocean, mountains). 2. Different traits will be selected for in each

location.3. Genetic differences will gradually accumulate

between the populations to a point that they can no longer interbreed.

The islands are small and close to each other, but have different environments.

Darwin noticed several kinds of small brown birds on the different Galapagos islands.

The bird’s beaks looked so different from each other that Darwin thought that they were unrelated…he was surprised to discover that all of them had a common ancestor.

coloration or markings of an animal serving to warn off predators

http://www.youtube.com/watch?v=GRSbC6HAgNE

a form of mimicry in which a harmless species has evolved to imitate the warning signals of a harmful species in order to avoid predators

Yellow jacket (left)Clearwing moth (right)

COMMON ANCESTOR:an organism from the past in which present organisms have evolved from

PAST

PRESENT

Fossil: Preserved remains or evidence of an ancient organism.

How are fossils formed? An organism dies and is covered by sediments before being rotted or eaten. It will become part of the sedimentary layer that becomes rock.

https://www.youtube.com/watch?v=SEDfRy6DQns

http://www.youtube.com/watch?v=c_DCP4cLVNg

https://www.youtube.com/watch?v=gLuwQ9AbfyA

The lower the layer is, the older the fossil is.

The higher the layer is, the younger the fossil is.

Homologous Structures: organisms with similar structure, but different function.

Analogous Structures: Different structure, similar function. These organisms DID NOT inherit their structural adaptations from a common ancestor.

Vestigial Structures: a structure that is no longer used by an organism, but is found in closely related species. (Ex. Human appendix and tail bone & whale hip bone).

Comparative Embryology: Embryos exhibit homologous structures

during certain phases of development, but become totally different structures in adult forms. All vertebrae embryos have a tail and paired

pharyngeal pouches. Fish gillsReptiles, birds, mammals ear, jaw and throat

Comparative Biochemistry: Scientists compare patterns of biochemical molecules (DNA, RNA and amino acid sequences). Evolutionary theory predicts that molecules in species with a recent common ancestor should share certain sequences.

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