1. Aim: How does evolution occur by natural selection?

2. How Does Evolution Occur?
EVOLUTION is a slow change in a _________ over time.
Evolution occurs by a process called _________________________.
species
NATURAL SELECTION
Read this cartoon, what do you think NATURAL SELECTION is?

3. Lamarck’s theory of Evolution
Lamarck believed that by the selective USE or DISUSE of characteristics, organisms lost or acquired certain traits that would be passed on to the offspring.

4. Darwin Considered the “_________” of evolution.
Charles Darwin traveled to the ___________________ , an uninhabited environment, where he studied evolution (_________________)
father
Galapagos islands
Darwin’s Finches

5. Natural Selection
KEY
NATURAL SELECTION is the _________ to Darwin’s theory.
According to this theory, evolution is controlled by __________ . Only the organisms that are able to ___________ and ________________ will pass on their genes.
NATURE
SURVIVE
REPRODUCE

6. Natural Selection vs. Artificial Selection
________ select the desirable traits that will appear in the
Offspring.
People
____________ selects
the desirable traits
that will appear in
the offspring.
Environment

7. Conditions that are vital to Evolution:
Overproduction
Variation
Struggle For Survival
Best Adapted To Survive
Darwin did NOT have knowledge of the _________ basis of inheritance
genetic

8. Overproduction leads to
More offspring are produced than can ___________ (most die young).
Organisms such as bacteria, fish, insects, and rabbits have ________ reproductive rates because the chance that their young will survive is___________.
survive
Overproduction leads to
COMPETITION!!
high
minimal

9. Variation
Variation: Individuals have__________ in their appearance, structure, or genes.
Source of variation:
_______ Reproduction (sperm + egg)
__________ (Indp. Ass. & Crossing Over)
__________ (Change in DNA)
differences
Sexual
Meiosis
Mutation

10. Mutations change the base sequence of ________. DNA
Most mutations are ___________, but some can help the organism ____________.
DNA
HARMFUL
SURVIVE

11. Best Adapted To Survive
The __________________ chooses which traits have adaptive value.
An individual that has traits favorable in a certain environment will live to _____________ and pass on those traits, others will _____ out.
ENVIRONMENT
reproduce
die

12. Struggle For Survival “Survival of the fittest”
Only those _________ suited will survive because of competition for ______ (limited) resources (___________________________)
BEST
finite
oxygen, water, food, and shelter

13. Patterns Of Change SHORT
Species with ________ reproductive cycles that produce ________ offspring tend to evolve more ________ than species with _________ life spans and ______ offspring.
Types:
a) Gradualism – evolution occurs _________ through time (Slow & Continuous) .
b) Punctuated Equilibrium- species stay the same for long periods of time and then change _______.
MANY
quickly
LONG
FEW
steadily
rapidly

14. Examples of Natural Selection
Industrial Melanism
Antibiotic / Pesticide Resistance

15. Antibiotic Resistance
Ex: Punctuated Equlibrium
When bacteria are exposed to an antibiotic there is a chance that a few will have a gene that makes them ____________.
The bacteria ___________ the resistance will be killed, while those that are __________ will ________ and pass on their genes for antibiotic resistance.
RESISTANT
WITHOUT
RESISTANT
survive
The antibiotic is the selecting agent
Resistant Bacteria
Antibiotic X

16. Extinction disappearance
The ______________ of an entire species (ex. Dinosaurs)
It can be caused by _______________________________________
___________________
temperature changes, pollution, or landscape changes