1. Happy Thursday! – 10/23 The diagram below represents a plant cell.
Which process takes place in structure A?
A cellular respiration
B heterotrophic nutrition
C digestion of fats
D protein synthesis

2. Happy Friday! – 10/24
A population of long-necked giraffes shares a habitat with a second population of organisms that eat the leaves of low-growing vegetation.
A scientist speculates that if the second population leaves the area, the giraffe population could exhibit shorter necks over time. Which mechanism could result in the giraffe population exhibiting shorter necks?
A The long-necked giraffes would breed with a short-necked
species.
B Giraffes with a genetic mutation for short necks would
survive and reproduce.
C The presence of food on shorter plants would lead to a
relaxation of giraffe necks.
D Giraffes would learn to bend their necks while feeding,
causing a shortening of neck muscles.

4. Everything must evolve…

5. Why do we accept this as a Scientific Theory?
What is Evolution?
changes in living organisms over time
explains how modern organisms have descended from ancient organisms
Why do we accept this as a Scientific Theory?

6. Evolution What we know, so far…. Many different species alive today
All life shares common characteristics
The Earth is very old
Life is very old
Life has changed over time
The changes have been little changes over long periods of time
Evolution
But how does this work?

7. Evolution explains Unity & Diversity
Evolution shows how organisms can be similar and how organisms can be different

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

9. Voyage of the HMS Beagle
Invited to travel around the world
(5 year journey!!)
records many observations of nature and took notes & drew pictures in hundreds of notebooks
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

10. 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

11. 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?

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

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

14. The finches clinched it for Darwin

15. 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

16. Darwin’s Finches Darwin’s conclusions: 1. Variations in beaks
differences in beaks in the original flock
adaptations to foods available on islands
2. Natural selection for most fit
over many generations, the beak adaptations allowed survivors to create the population diversity
3. Offspring inherit successful traits
Best adaptations allow offspring to out-compete others and survive to reproduce
4. This creates new species over time

17. Earlier ideas on Evolution
LaMarck
evolution by acquired traits
Organisms change their adaptations through use
Give those new adaptations to their offspring
example
in reaching higher leaves giraffes stretch their necks & give the acquired longer neck to offspring
not accepted as valid

18. Darwin’s view of Evolution
giraffes that already have long necks survive better
leave more offspring who inherit their long necks
variation
selection & survival
reproduction & inheritance of more fit traits 

19. What is Natural Selection?
Competition
for food, mates, nesting sites, escape predators
Fitness = having the right adaptations to out-compete others
Survival of the Fittest = organisms with the “best” traits/adaptations survive to reproduce

20. Survival & Reproduction of the fittest
not the biggest…
…the fittest!
not the fastest…
not the bravest…
not the strongest…
Adaptations
the traits that help an organism fit the environment better to
survive & reproduce

21. Descent With Modifications
Darwin concluded:
Each species has descended, with changes, from other species over time.
Darwin called this…
Descent With Modifications or
evolution
(change in population over time)