Warm Up: 11/24 (Back of the NB)

1. Which of these would not be used by a scientist to determine the evolutionary relationship between two species?A. bone structureB. fossilsC. DNAD. population size

In a sentence justify your

answer.

Warm Up: 11/24 (Back of the NB)

1. Which of these would not be used by a scientist to determine the evolutionary relationship between two species?A. bone structureB. fossilsC. DNAD. population size

Bones structure, fossils and DNA can all be used to determine

ancestry. Population size can not.

Warm Up: 11/24 continued…

2. Which of these is least likely to show common ancestory?A. homologous structuresB. DNAC. analogous structures

In a sentence justify your

answer.

Warm Up: 11/24 continued…

2. Which of these is least likely to show common ancestory?A. homologous structuresB. DNAC. analogous structures

Analogous structures show

common functions, but do not come

from common ancestors.

Natural Selection

natural selection

“survival of the fittest”

process by which organisms that are best suited to a particular environment survive and reproduce.  

Darwin’s Theory of EvolutionDarwin’s Theory Includes 5 Ideas1. Organisms have _____________________________, and those variations are _________________________ to the organisms’ babies. 2. Some variations are ___________________________ (better than others). 3. More offspring are _________ than can _____________________. 4. Those that __________ have _____________________ and ____________. 5. Because of this, ______________________________________________.

Darwin’s Theory of Evolution

Darwin’s Theory Includes 5 Ideas1. Organisms have ___Variations_________, and those variations are _passed down_____ to the organisms’ babies. 2. Some variations are __favorable____ (better than others). 3. More offspring are __produced___ than can _survive_. 4. Those that _survive__ have ___favorable traits ___ and _will reproduce___________. 5. Because of this, ___a population will change over time_.

Mutation

mutation Causes a genetic variation

a change in a gene or chromosome

Genetic Variation

genetic variation

differences that exist naturally among members of a population or species.

Adaptation

adaptation polar bears have thick, waterproof

fur for insulation

in the arctic

traits that help an organism survive in a given environment.

Survival of the Sneakiest Cartoon

Cast Members:• Narrator• Picnic Guy• Big, Strong Cricket• Female Cricket• Sneaker Cricket• Bat• Misc Parts

Survival of the Sneakiest Cartoon

• What was the mutation in the story?• What trait(s) will be passed down to the baby

crickets?

• How is this an example of natural selection?

Things to think about…

•Mutations cause genetic variations.•Genetic Variations that are favorable, result in the organism being best “fitted” for its environment.•“Survival of the Fittest” refers to a variation or adaptation that allows an organism to survive and reproduce.

Natural Selection Practice - 1

There are 2 types of worms: worms that eat at night (nocturnal) and worm that eat during the day (diurnal). The birds eat during the day and seem to be eating ONLY the diurnal worms. The nocturnal worms are in their burrows during this time. Each spring when the worms reproduce. They have about 500 babies but only 100 of these 500 ever become old enough to reproduce.

Natural Selection Practice - 2

There are 3 types of polar bears: ones with thick coats, ones with thin coats and ones with medium coats. It is fall, soon to be winter. The temperatures are dropping rapidly and the bears must be kept warm, or they will freeze to death. Many of the bears have had 2 cubs each but due to the extreme temperatures, many mothers only have one cub left.

Natural Selection Practice - 3

In ostriches, there are 2 types: ones that lay eggs with thick shells and ones that lay eggs with thin shells. Eggs with thick shells are harder to break into and eat. A flock of ostriches had 10 eggs. But 6 of them were eaten by rodents before they could hatch.

Natural Selection Practice - 4

There are two types of rabbits: those that strictly eat grass and those that strictly eat berries and flowers. A drought occurs one year, and the plants have difficulty producing any extras (flowers, berries, etc.). They can only try and keep themselves green. At the beginning of the year, there were 1200 rabbits. By Autumn, 300 rabbits have starved to death.

Extinction

extinction the permanent dying out of a species or a larger group of organisms.

Homework:

Work on Study Guide! Study Vocabulary!

The Pilosa Population

Once upon a time, there was an animal called a pilosa that caught insects with its trunk. Some pilosas had wide trunks. Others had skinny trunks. When habitat changes caused their dinners to tunnel underground, pilosas with wide trunks began to starve and die. The pilosas with thin trunks could still reach the bugs. So they stayed healthy and had babies that also had thin trunks. Eventually, all pilosas had skinny trunks and they lived happily ever after. Or they might have, if they were real.