1. How do life forms (organisms) change over time?
The Big Question for chapter 6 is:
How do life forms (organisms) change over time?

2. Theories of Evolution
Chapter 6 Lesson 1

3. 2 Men= 2 Theories
Evolution: changes over time.

4. 1st Theory for Evolution: Theory of Evolution by acquired characteristics.
Author: Jean Baptiste Lamark
Traits developed during parent’s life (acquired traits) are inherited by offspring.
Example: A parent that develops large muscles will pass those to their offspring.
We know that the evidence from Gregor Mendel did not support this.

5. 2nd Theory of Evolution: Theory of Evolution by Natural Selection
Author: Charles Darwin
Organisms with traits best suited for their environment are more likely to survive and reproduce so they pass those traits on to their offspring.
Example: beaks of Finches on Galapagos islands.

6. 5 Principles to Natural Selection
Organisms produce more offspring than what can survive.
Variations exist within a population.
Variations are inherited. (passed from parent to offspring)
Some variation are helpful= survive, reproduce, pass traits on.
So, a population will change over time.

7. Variation vs Adaptation
Variation= any differences between organisms of the same species.
variations arise from mutations

8. Adaptation vs Variation
An accumulation of variations can become adaptations which increases an organisms chance for survival.
Mutations: Result in a change in the DNA.
Examples of mutations that are adaptations:
Camouflage
Mimicry

9. Camouflage vs Mimicry
Camouflage: an adaptation that allows animals to blend in with certain aspects of their environment. 
Camouflage increases an organism's chance of survival by hiding it from predators.

10. Camouflage vs Mimicry
Mimicry: a protective resemblance.

11. Factors that Affects Variation and Adaptation
Environmental factors: When the environment becomes to stressful populations will move in or out of an area, and they take with them or bring genes of variation.
events/2012-news/SchusterMiller7-2012

12. Example:
Adaptations usually develop in response to a change in the organisms habitat.  A famous example of an animal adapting to a change in its environment is the English peppered moth. Prior to the 19th century, the most common type of this moth was cream- colored with darker spots. Few peppered moths displayed a mutation of being grey or black.
As the Industrial Revolution changed the environment, the appearance of the peppered moth changed. The darker-colored moths, which were rare, began to thrive in the urbanatmosphere. Their sooty color blended in with the trees stained by industrial pollution. Birds couldnt see the dark moths, so they ate the cream-colored moths instead. The cream-colored moths began to make a comeback after the United Kingdom passed laws that limited air pollution.

13. Factors that Affects Variation and Adaptation
2. Geographic isolation: a small number of species isolate from rest of population become different from main population over time.
m/animals/mammals/r/ring-tailed- lemur/

14. Example: The wide variety of marsupials in Oceania is an example of how organisms adapt to an isolated habitat. Marsupials, mammals that carry their young in pouches, arrived in Oceania before the land split with Asia. Placental mammals, animals that carry their young in the mothers womb, came to dominate every other continent, but not Oceania. There, marsupials faced no competition.

15. Factors that Affect Variation and Adaptation
3. No variation: all species have an equal chance at surviving and reproducing.

16. Factors that Affects Variation and Adaptation
4. Competition: Different species compete for resources.
and-veterinary-medicine/zoology-general/competition-biology

17. Example
Adaptations have allowed hundreds of varieties of cichlids to live in Lake Malawi. Each species of cichlid has a unique, specialized diet: One type of cichlid may eat only insects, another may eat only algae, another may feed only on other fish.

19. Speed of Evolution
How long do you think evolution takes?

20. 2 Models for the Speed of Evolution
Gradualism: Species change is slow and ongoing.
Punctuated Equilibrium: Species change is rapid. (few thousand- million years).
Article link: equilibrium

21. 1. Gradualism

22. 2. Punctuated Equilibrium