1. Unit 7: Evolution & Natural Selection

2. (1) Genetic Variation
Genetic Variation / Diversity  Organisms inherit different variations of traits, giving them different strengths and weaknesses.
Genetic Variation allows for some individuals to succeed + survive.

6. (2) The Struggle for Existence
Living things are always competing to stay alive AND pass on their genes:
There is limited food, water, shelter.
There are changes in climate, disease transmission, etc.
Those who can survive and reproduce during tough times are best suited/adapted to their environment.

8. (3) What does it mean to Adapt?
To have the traits necessary to remain living and sexually attractive during times of change.
It does NOT mean: To change/grow body parts so that you can survive that moment.

9. (4) Evolution
A change in the allele frequency of a population of living things, over a period of time.
“Allele Frequency” = How often a certain trait shows up in the population.

12. (5) NOT Evolution
Sudden, quick physical changes to individuals so that they can survive.
Change in populations so that only the “more perfect” versions live on.
Humans “coming from” monkeys.

14. (6) What causes/drives Evolution?
Genetic variation in a population.
Changes in the environment/resources.
Changes in sexual preference.
The dying/extinction of certain populations.

15. (7) Evolution Mechanisms (EM)
All evolutionary changes and mechanisms are still driven by natural selection.
But there are different types of events that can drive evolution.
End Result is ALWAYS the same:
There will be a change in the allele frequencies in the population.
Could produce a new species (a group of organisms that can only reproduce with each other).

16. (8) Natural Selection
As the environment changes, certain characteristics amongst living things will help them to survive (Survival of the Fittest).
If you don’t have these characteristics, you will not reproduce, or will die.

20. (9) Genetic Drift
The random removal of certain traits (alleles) from a population.
“Wrong Place, Wrong Time.”

22. (10) Genetic Migration
When organisms with different traits move into new regions and populations, and reproduce with the original organisms.

24. (11) Geographic Isolation
When a diverse population is separated and isolated by some geographic barrier (land, water, climate).

27. Natural Selection video
Now Let’s Watch This Video…
Natural Selection video
Hummingbirds YouTube Video