1. Variations within a species are most likely the result of
Aim: Darwin’s Natural Selection
Enter Date
Warm-up:
Variations within a species are most likely the result of 
(1.) mutations and sexual reproduction  
(2.) mitosis and asexual reproduction  
(3.) synapsis and disjunction 
(4.) overpopulation and recombination
HW:
Regents Biology

2. Lamarck Was born in 1744 in Northern France
Dedicated his life to studying how animals grow.
He is the first to propose mechanisms explaining how organisms change over time.
Regents Biology

3. Use and Disuse
The theory that an organism could alter the size or shape of a particular organ by using their bodies in new ways.
Example – by trying to use their feet for flying, birds could eventually grow a second set of wings.
Example – if a bird did not use its wings, it would lose it.
Regents Biology

4. Inheritance of Acquired Traits
The theory that during if an animal acquires a trait during its lifetime, it can pass it to its offspring.
Example – You dye your hair red, your children will be born with red hair.
Regents Biology

5. Charles Darwin Proposed a way how evolution works
How did creatures change over time?
by natural selection
Collected a lot of evidence to support his ideas
What did Darwin say?
What evidence supports Evolution by Natural Selection?
What impact did Evolution have on biology?
Regents Biology

6. Natural Selection
The idea that individuals that are better suited for their environment will survive and reproduce most successfully.
For example – a fish will survive better in the ocean than a human will.

7. Voyage of the HMS Beagle
Invited to travel around the world
(22 years old!)
makes many observations of nature
main mission of the Beagle was to chart South American coastline
After graduation Darwin was recommended to be the conversation companion to Captain Robert FitzRoy, preparing the survey ship Beagle for a voyage around the world.
FitzRoy chose Darwin because of his education, his similar social class, and similar age as the captain.
Darwin noted that the plants and animals of South America were very distinct from those of Europe
Robert Fitzroy
Regents Biology

8. Voyage of the HMS Beagle
Stopped in Galapagos Islands
500 miles off coast of Ecuador
The origin of the fauna of the Galapagos, 900 km west of the South American coast, especially puzzled Darwin.
On further study after his voyage, Darwin noted that while most of the animal species on the Galapagos lived nowhere else, they resembled species living on the South American mainland.
It seemed that the islands had been colonized by plants and animals from the mainland that had then diversified on the different islands
Regents Biology

9. Galapagos Recently formed volcanic islands
Most of animals on the Galápagos live nowhere else in world, but they look like species living on South American mainland
Regents Biology
800 km west of Ecuador

10. Darwin found…many unique species
Many of Darwin’s observations made him wonder… Why?
Darwin asked:
Why were these creatures found only on the Galapagos Islands?
Regents Biology

11. Darwin found…clues in the fossils
present day Armadillos
Darwin found…clues in the fossils
Darwin found:
Evidence that creatures have changed over time
ancient Armadillo
Darwin asked:
Why should extinct armadillos & modern armadillos be found on same continent?
Regents Biology

12. Darwin found: Different shells on tortoises on different islands
Darwin asked:
Is there a relationship between the environment & what an animal looks like?
Regents Biology

13. Darwin found… birds He thought he found very different kinds…
Many different birds on the Galapagos Islands.
He thought he found very different kinds…
Regents Biology

14. But Darwin found… a lot of finches
Darwin was amazed to find out:
All 14 species of birds were finches…
But there is only one species of finch on the mainland!
Darwin asked:
If the Galapagos finches came from the mainland, why are they so different now?
Large ground finch
Small ground finch
Finch?
Sparrow?
Regents Biology
Warbler finch
Tree finch
Woodpecker?
Warbler?

15. The finches cinched it! different beaks are inherited variations
serve as adaptations that help birds compete for food
these birds survive & reproduce
The finches cinched it!
Darwin found:
The differences between species of finches were associated with the different food they ate
Large ground finch
Big seed eater
Small seed eater
Small ground finch
Regents Biology
Warbler finch
Insect eater
Tree finch
Leaf & bud eater

16. Relationship between species (beaks) & food
Regents Biology

17. Darwin’s finches Darwin’s conclusions variations in beaks
differences in beaks in the original flock
adaptations to foods available on islands
natural selection for most fit
over many generations, the finches were selected for specific beaks & behaviors
offspring inherit successful traits
accumulation of winning traits: both beaks & behaviors
separate into different species
Regents Biology

18. From 1 species to 14 species…
Warbler finch
Woodpecker finch
Small insectivorous
tree finch
Large
insectivorous
Vegetarian
Cactus finch
Sharp-beaked finch
Small ground
finch
Medium
ground finch
Large ground
Insect eaters
Bud eater
Seed eaters
Cactus
eater
Warbler
Tree finches
Ground finches
natural selection for best survival & reproduction
variation
Regents Biology

19. Who is the Fittest? Who would survive the best in the arctic?
A. Polar Bear
B. Grizzly Bear
C. Brown Bear

20. Darwin’s Great Journey
While he was observing animals, Darwin discovered many things about the way animals adapt. He noticed:
1. Overproduction
2. Competition
3. Variation
4. Adaptation
5. Speciation

21. Overproduction
Producing far more offspring than your environment can handle
Leads to a struggle for survival.

22. Competition
Each individual in an environment must compete in order to survive.
For example – if we were stranded in the high school and they had a pizza in the gym, each person would compete to get there and eat before the rest of the class.

23. Fitness The ability an individual has to compete in an environment.
For example – If you and Bear Grylls were stranded in Alaska, who is more fit to survive?

24. Variation Our genes make us different from one another.
Variation gives a species a bigger chance of survival.
For example – some humans are natural swimmers. If Long Island sank and we had to swim across to Connecticut, the swimmers would survive.

25. Adaptation
Inherited characteristic that increases an organism’s chance of survival.
For example – The mud skipper adapted the ability to breathe out of water because his habitat changed.

26. Speciation Formation of a new species
For Example – before homo sapiens, homo rhodensiensis could not speak. A new species evolved that could speak called homo sapiens.