Variation and Natural Selection Notes Mutations Variations Natural Selection Adaptations Selective Breeding How Does All of This Fit Together? Evolution.

Variation and Natural Selection Notes

Mutations

Variations

Natural Selection

Adaptations

Selective Breeding

How Does All of This Fit Together?

Evolution

Charles Darwin

Charles DarwinScientist during the 1800’s that traveled around the world making observations of nature.

Darwin discovered from his travels that organisms have structural characteristics that enable them to live in their environment – Adaptations!

Background Information


Darwin’s FinchesAs Darwin was observing birds on the Galapagos Islands, he discovered that there were many variations of one kind of bird – the Finch.

Variations are differences in form of an organism within the same species or group.



Darwin’s Finches (Continued)These birds that would later become nicknamed as “Darwin’s Finches” proved that organisms adapt to live in their environment.

Each of Darwin’s Finches have a beak that is specifically designed to eat the type of food that is available in its environment.



Darwin’s Finches (Continued)Each one of these Finches was found on a different Galapagos Island. This illustration shows how various Finches adapted to eat the type of food available to them.



How Do Adaptations Come About?

How Do Adaptation Come About?


MutationsA mutation is where there is a random change in genetic information in an organism.

Mutations can be good and they can be bad.


If a mutation is good, it will help and organism to live.

If a mutation is bad, it will often cause the organisms to die.


MutationsGood or Beneficial Mutations

Below is a picture of a Black Jaguar (Left). This color mutation is good because it helps the Jaguar to hunt at night, blending into the night time landscape.



MutationsBad or Harmful Mutations

Below is a picture of a two headed calf . This type of mutation is bad because the animal is not able to survive.



VariationsGood mutations lead to variations.

When mutations are good, the organism survives to pass the mutation on to it’s offspring. As more and good mutations are passed on, more variations of a species become present as in these parakeets below.



Natural SelectionMutations which lead to variations also lead to natural selection.

Natural selection occurs when good mutations are passed on to offspring.


Natural selection is often referred to as “Survival of the Fittest”. Organisms that have “stronger” mutations or characteristics survive and the organisms that have “weaker” characteristics die.

The organisms with the stronger characteristic are able to pass their stronger characteristics on to their offspring. The organisms with the weaker characteristics die and are unable to pass their weaker characteristics on.


Natural Selection Example



Natural Selection Example (Cont.)



Natural Selection Example (Cont.)



AdaptationsOver very long periods of time, the good mutations that get pass on and on over several generations become known as adaptations.


Adaptations take hundreds, thousands, or even millions of years to come about.

If an organism is not able to adapt, it will die. If an entire species is unable to adapt, the whole species will die and become extinct.


Selective BreedingSelective breeding is when animals are bred on purpose to bring about desired traits.


Below is a picture of a horse (left) and donkey (middle) and a mule (right). When a horse is bred with a donkey a mule is produced. A mule has the strength of a horse and the sure footedness of a donkey.


http://upload.wikimedia.org/wikipedia/commons/4/40/Frecklesmule.jpg

Selective BreedingSelective breeding is when animals are bred on purpose to bring about desired traits.


Below is a picture of a horse (left) and donkey (middle) and a mule (right). When a horse is bred with a donkey a mule is produced. A mule has the strength of a horse and the sure footedness of a donkey.


http://upload.wikimedia.org/wikipedia/commons/4/40/Frecklesmule.jpg

Selective BreedingSelective breeding can also bring about bad or undesirable traits


Some breeds of dogs are selectively bred for their aggressiveness, however, this sometimes produces dogs are too aggressive an cannot be controlled.


EvolutionEvolution is the end product of adaptations. As mutations, variations, natural selection, and adaptations occur, organisms continue to change to become ever better suited for their environment.



Evolution The evolution of the horse.


The modern day horse may have looked something like a dog, but over millions of years of natural selection and adaptations, this animal changed into what we now know as a horse.


Variation and Natural Selection Notes Mutations Variations Natural Selection Adaptations Selective Breeding How Does All of This Fit Together? Evolution.

Documents

mutations good

notes mutations variations

variations good mutations

mutations bad

stronger mutations

harmful mutations

beneficial mutations

darwins finches