This document provides notes on natural selection. It begins by stating the objective is to explain how natural selection works. It then outlines the four main steps of natural selection: 1) overproduction where each species produces more offspring than will survive, 2) genetic variation between individuals provides different traits that help or hurt survival, 3) struggle to survive and competition for limited resources means only some individuals survive to adulthood, 4) successful reproduction where the individuals best adapted to the environment are more likely to survive and pass on their genes, leading to evolution over long periods of time. Examples of adaptations like camouflage and fast swimming are provided. The document asks questions to check understanding of natural vs artificial selection and factors controlling natural selection.

1. Natural Selection Notes
OBJECTIVE:
You will be able to explain how natural
selection works

2. Natural Selection Notes
“How the changes in the
environment can bring
about changes in species”

3. 1. Artificial selection – breeding animals
and plants for certain characteristics

7. 2. Darwin explains evolution
a. 1858 Darwin writes “The Origin of Species”,
explains evolution through the theory of
NATURAL SELECTION.
b. Natural selection – the process where
individuals that are better adapted to their
environment are more likely to survive and
reproduce than other members of the same
species. (“Survival of the Fittest”)

8. NATURAL SELECTION
Step 1: OVERPRODUCTION – each species
makes more offspring than will survive

10. NATURAL SELECTION
Step 2 – GENETIC VARIATION –
Any difference between individuals of the same
species
- some traits help, some hurt them.
- Some variations are helpful = adaptation

11. Step 2 – GENETIC VARIATION
Not everyone is identical
a. Different genes = different traits
b. Fast swimmers, better camouflage

12. NATURAL SELECTION
Step 3: STRUGGLE TO SURVIVE - COMPETITION
– A natural environment doesn’t have enough
resources for everyone, so only some
individuals survive to adulthood.

13. Step 3 - Competition:
Usually indirect – no actual physical fights
Not enough food, not be able to escape from
predators
Only strong organisms will survive long enough to
reproduce

14. NATURAL SELECTION
Step 4: SUCCESSFUL REPRODUCTION
– the individuals that are well adapted to the
environment are more likely to survive and
reproduce. Their genes will be passed on.
**Over a long period of time, natural selection
can lead to evolution.**

18. The Heike or Oni-gani (“demon spirit” crab, Dorippe japonica),
whose name derives from a Japanese legend. The pattern on
its shell is thought to resemble the face of a Samurai warrior.
Natural or artificial selection? Intentional or accidental?

19. Sexual Selection (“Darwin’s headache”)

20. Archaeopteryx,
discovered 1861

24. Exit Slip
1. Give me an adaptation that rabbits have to
help them survive?
2. A factor that controls natural selection is
a. Inheritance of acquired traits
b. Unused traits become smaller
c. Organisms produce more offspring than can
survive
d. The size of the organism