1. Adaptation,Variation and Natural Selection
March 27TH

2. Adaptations and Survival
An adaptation is a structure, behavior or physiological process
These help an organism to survive and reproduce in particular environment
Example: camouflage/mimicry
Can you find the “hidden organisms” in the following slide?
Camoflauge is genetice the genes for camoflauge were more prevalent therefore that species survived

6. Mimicry (mimic environment)/Camouflage

7. Other Adaptations Biochemical and Body Processes Structural Adaptation
Hibernation in ground squirrel
Structural Adaptation
Sharp talons and excellent vision of owl
Thick leaves of buffalo berry that help to reduce the water loss on hot summer days

8. Adaptation
Different kinds of teeth for different animals, say carnivore ripping teeth and herbivore grinding teeth
Different tissues within species
Heart vs. eye etc.

9. How do These Adaptations Develop?
They are a result of a gradual change of characteristics over time
A variation that helps an individual in a population is likely to be passed on from survivor to survivor
Some variations help and some do not, not all variations become adaptations!

10. Variation Within a Species

11. Let’s Look at Our Variations!
Question: Are there measureable differences in sizes among individuals of a species?
Two students from each table, measure your thumb and your middle finger
Collect the data and graph this information
Draw a data table and a bar graph that best suits the data gathered
Conclude what you see with this data

12. How does variation within a species occur?
Biological Species
A group of reproductively compatible populations
How does variation within a species occur?

13. Genetics
Organisms that reproduce sexually have a blueprint from both parents
Through this reproduction, particular traits are passed on to the new organisms

14. Mutations Mutations are genetic changes that happen in DNA
Occur from mistakes that happen when DNA is being copied

15. Natural Selection: It is the production of variations due to:
Mutations: Changes in the DNA
Random mate selection & fertilization
Do we see variation within different wild species ?

16. Natural Selection
Individuals with favorable traits are more likely to leave more offspring better suited for their environment.
Example:
English peppered moth (Biston betularia)
- light and dark phases

17. Humans select traits for dogs, pigeons and other animals when they breed them (we call this ARTIFICIAL SELECTION).
Bred dogs came from a single original species

18. Natural Selection is Survival of the fittest
NOBODY!!
There is no agent involved in natural selection.
Natural selection is a process of elimination
INDIVIDUALS THAT HAVE TRAITS THAT ARE BEST ADAPTED FOR THE CURRENT ENVIRONMENT ARE THE ONES THAT SURVIVE TO BREED AND PASS ON THEIR GENES TO THE NEXT GENERATION.
Organisms not possessing the beneficial traits either die or don’t have as many offspring.
Natural Selection is Survival of the fittest