Evolution

Theory

An explanation of some aspect of the natural world that is confirmed by evidence.Observations, data, laws, and confirmed hypothesis.

Charles Darwin

HMS BeagleStudied the Galapagos IslandsTried to determine where different species came fromStudied similarities and differences.

Evolution

The process of change where new species develop from existing species over time. Species change over MANY generations to become better adapted to their new conditions.Change as the Earth changes.

Evidence for Evolution

DNA: the sequence of DNA can tell us how closely related different organisms are.Or how closely related different SPECIES are.

FossilsThe fossil record shows scientists what kind of creatures lived millions of years ago.Scientists can find out when these organisms lived in two ways.

1. Relative Dating: Where the fossils are underground

2. Carbon Dating: Measuring the amount of Carbon in the fossil.

Fossils

Body fossils show us what a plant or animal looked like.

Fossils

Footprints and coprolites (fossil poop) are trace fossils - they show us how an animal lived.

Finding Fossils

Scientist must search for fossilsOnce found fossils must be carefully extracted from the rock around them.

Adaptations

Any characteristic of an organism that improves its ability to survive and reproduce in its environment.Darwin studied the adaptations of Finches.He missed the adaptations of the Giant Tortoise.

Niches

The place or function of an organism within its environment.This can include: where it lives, what it eats, where it eats, when its active, when it reproduces, etc.Koalas have a narrow (small) niche– Only eat a few species of Eucalypt Trees

Crows have broad (large) niche– They can live in a variety of places and can eat a

variety of things.

Natural Selection

Individuals of a species are better adapted to their environment are more likely to survive and reproduce than other members of the same species.

Galapagos Tortoise AdaptationsSaddleback Tortoise Lives in dry region leaves high in trees Highly arched shell opening Long neck Long legs

Domed TortoiseLives in area of thick vegetation Eats grasses and leaves close to groundLow, rounded shell openingShort neck  Short legs

                                          

                         

Which is Which

Saddleback or Domed Tortoise?

Would a Saddleback survive in the same area Domed Tortoises survive?

                                          

                         

                                          

                         

Interesting Adaptations

Displays of strength to attract mates:Female Great Reed Warblers only mate with males that can sing a wide range of tunes. Both male and female parrots are attracted to those with fluorescent plumage. It actually glows by absorbing ultraviolet (Sun) light. Humans cannot see it, except under fluorescent lights.The ideal man for a female peacock is one with the most eyes, oceli, on its spectacular tail.Female butterflies also choose mates with the biggest eyespots on their dorsal wings.

Adaptations to Compete for Space/Food

A giant panda that upends itself into a handstand may be sending a message that it's one big bamboo-thrasher and not to be messed with.In a dispute fruit flies will Sumo wrestle. Scientists observed fights where the flies push each other out with their forelimbs out of the arena (piece of fruit).Hummingbirds are master swordsmen. The tiny birds will dive-bomb other birds that are a threat to their territory. Their needle sharp bill can even fatally stab and enemy.

Adaptations for Survival

Some animals can mimic others.To frighten off predators the California gopher snake will spread out the back of their heads, hiss, and vibrate their tails to look like a rattlesnake.Stick insects look like twigs, they also produce eggs that look like and SMELL like seeds to deter predators from eating them.The peacock butterfly flashes its eyespots on its wings when in danger. The attackers is momentarily confused, unsure if they are facing a blinking owl or another large bird. Meanwhile, the butterfly escapes.

Peacock Butterfly