Evolution Basics
1. Mutation- This can only occur when new allies form. These alleles can be harmful or helpful. If the alleles is helpful the trait will be passed along and will become more common as individuals without the alleles die off.
2.Genetic Drift - a random change in allele frequency.
a. founder effect- small population with one mutation that is passed through population due to interbreeding.
b. population bottleneck- a environmental disaster happens and wipes out a population leaving only a few.
3. Migration- most of a cretin population moves from one environment to another.
4. Natural Selection- Survival of the fittest.
2.Genetic Drift - a random change in allele frequency.
a. founder effect- small population with one mutation that is passed through population due to interbreeding.
b. population bottleneck- a environmental disaster happens and wipes out a population leaving only a few.
3. Migration- most of a cretin population moves from one environment to another.
4. Natural Selection- Survival of the fittest.
Evidence of Evolution
1. Fossil record- Fossils found in different places show how animals have changed over time. We can see from fossils that whales once had legs, it seems as though they lived on land and were descendants of dinosaurs.
Relative Dating is used to tell how old a fossil is. the deeper in the layers of rock it is found, the older it is. In the diagram to the left you can tell that layer E is one of the oldest layers
2. geography and species- Similar fossils that are found in different parts of the world show that when the continents were connected, animals were the same. As the plates moved and weather changed, the animals adapted to survive.
3. Comparative anatomy- many bone structures that mammals have are similar. This shows that we evolved from the same ancestors but evolved in different ways to meet the necessary anatomy and to live.
CASE STUDY
Evolution is the change of a spices over time. This is caused by different allele frequencies that allow a certain individual to survive in there habitat better. this is called survival of the fittest. In the example of this is shown to the right. Two types of Peppered moth exist. A black and a black and white. The Trees in there habitat were Black and white so the Black moths would be seen and eaten, therefore not reproducing. However, Coal started to be used and bade the trees back, suddenly the black and white moths could be seen and the black moths thrived.
Birds
Birds are thought to have evolved from dinosaurs. Big scaly beasts morphed into big scaly beings small arms. These arms slowly evolved into wings. Birds adapt in order to survive and reproduce. Different birds need different size and shaped beaks. The father of evolution Darwin, found that on different islands of the Galapagos the same bird varied. longer and sharper beaked birds lived on and island where the food source was bugs that had to be picked out of trees, where as birds with short strong beaks lived off of nuts and berries on a different island. He believed that these birds had changes over time in order to better survive on there island.
Special Adaptations
~snowy owls have adapted to blend in with their environment
~one ear is higher than the other ear allowing sounds to be picked up from different altitudes
~stiff feathers around there eyes direct sound waves to there ears
~one ear is higher than the other ear allowing sounds to be picked up from different altitudes
~stiff feathers around there eyes direct sound waves to there ears