Evolution Part I:

Charles Darwin is known as the Father of Evolution Charles Darwin is known as the Father of Evolution. What we know now seems like common sense but in Darwin’s day, it wasn’t. So…..How did Darwin come up with his new and radical ideas that eventually led to the (controversial) Theory of Evolution?

After studying at Cambridge, Charles was recommended for a surveying trip on the HMS Beagle. He sailed around the world on the Beagle for 5 years, working as a naturalist.

On the voyage, Darwin noticed that everywhere he went, the animals and plants differed vastly. Yet, there were similarities Patterns in the species suggested that the species had changed over time and had given rise to new and different species.

“Galapagos” means turtle. Many of Darwin’s conclusions were based on observations of wildlife in the Galapagos Islands. The Galapagos Islands lie 500 miles west of Ecuador in the Pacific Ocean, directly on the equator. “Galapagos” means turtle.

Were the animals and plants created to match their environment? Then, why didn’t the Galapagos finches look like the birds of the African continent, since the environments of both the Galapagos and Africa were similar.

Darwin guessed that some of the birds from South America migrated to the Galapagos. Once on the islands, the birds must have changed over the years because each island was different from the others….landscape and flora.

Descent With Modifications Darwin concluded: Each species had descended, with changes, from other species over time. Darwin called this… Descent With Modifications or evolution (change in species over time)

…or Survival of the Fittest. The mechanism by which evolution takes place. Natural Selection …or Survival of the Fittest. Five basic components:

1. All species have genetic variation. Nature has to have some variety in order to choose. Look around you…are you all the same?

2. Organisms produce more offspring than can survive 2. Organisms produce more offspring than can survive. Many that survive do not produce offspring. The female green sea turtle lays a clutch of about 110 eggs. She may lay several clutches. It is likely that less than 1% of the hatchlings will ever reach sexual maturity.

3. Since more organisms are produced than can survive, there is competition (struggle for existence). Competition exists WITHIN and AMONG species. Within and Among Species for food water shelter space And Within a Species for mates

Short-term natural disasters can have large impacts on competion Short-term natural disasters can have large impacts on competion. (drought, fires, floods, snowstorms, hurricanes, and tornadoes) Mineral Management Service photo courtesy of GeekPhilospher.com http://geekphilosopher.com/bkg/snowAlaskaIce.htm Long-term changes in the environment also affect survival. (ice ages, biome shifts, global warming etc)

He who spreads the most genes wins! 4. Survival of the fittest Some organisms are more suited to their environment as a result of variations in the species. Fitness: the ability of an individual to survive and reproduce in its specific environment. Fitness is a result of adaptations. Individuals that are fit to their environment survive and leave more offspring than those who aren’t. He who spreads the most genes wins! 1st

5. Descent with modification: Living species today are descended with modifications from common ancestral species that lived in the past. Characteristics of fit individuals increase in a population over time. Over time, genes for less favored characteristics will be eliminated from the gene pool. Example: giraffes and their increasingly longer necks.

Natural Selection: Survival of the Fittest An adaptation is any inherited characteristic (a genetic variation) that can increase an organism’s chance of survival. An organism does not change because of the need or desire to survive. The organism is either born with the variation that enables it to survive or it dies. the variation has to already exist. If the environment changes. the variation may give an advantage to survive environmental change.

On the Origin of Species Darwin published his theory in the book November 24, 1859 On the Origin of Species And that is why Darwin is the father of Evolution

Natural Selection in Action Camouflage (Cryptic coloration)

Natural Selection in Action Mullerian Mimicry –untasty imitates untasty ….both benefit by making sure their predators gets the point. Monarch and Viceroy Butterfly

Natural Selection in Action Batesian Mimicry – palatable (tasty) mimics unpalatable (untasty) Coral vs. King Snakes: Red on yellow, kill a fellow, red on black friend of Jack

Natural Selection in Action Warning Coloration (Aposematic coloration)

Natural Selection in Action Disruptive Coloration

Natural Selection in Action Counter Shading

Natural Selection in Action Eye spots

Evolution Things to remember: a. Populations evolve, not individuals. b.  Natural selection is the mechanism of evolution. c.  Evolution occurs by chance (NOT GOAL ORIENTED). d. Organisms are born with adaptations, they can’t adapt because they need or want to