1. Evolution
Change Over Time

2. Evolution Refers to the process through which species change over time
This change results from a difference in the genetic material of an organism and that successful trait being passed from one generation to another.

3. Influential Scientists
Jean Baptiste de Lamarck
Charles Darwin

4. Jean Baptiste de Lamarck (1744-1829)
Believed that the fossil record showed that the species had changed over time
Around 1800, he proposed that an organism could ACQUIRE a new trait during its lifetime and then pass that trait on to its offspring
Unfortunately he was unable to provide evidence to support this idea.

5. Jean Baptiste de Lamarck
Inheritance of Acquired Characteristics

6. Charles Darwin ( )

7. Charles Darwin Studied medicine at Cambridge University
Witnessed surgery on a child…quit medicine
Dropped out of College
Studied botany with Professor Henslow
Decides he wants to become a naturalist like Henslow
Professor John Henslow & George Peacock invite him to be the Naturalist aboard the H.M.S. Beagle
They travel to South America and explore for 5 years

8. Charles Darwin
After the trip, when he returned to England, he came up with the modern theory of evolution, using his research from the 18 different Galapagos Islands.

9. On The Origin of Species
Collected massive amounts of data while on his trip
(3 volumes of 1,000 pages a piece)
Did not publish his book for 20 years
For fear of how people would react

10. Answer the following question
Why is Charles Darwin important today?
Restate the question in your answer.

11. Darwin’s Tortoises

12. Darwin’s Tortoises Tortoises:
Darwin noticed that tortoises with short necks were living in damp areas with abundant plant life that grew close to the ground.
Longer necked tortoises were living in dry areas with cacti.
He considered whether the lengths of their necks made it possible for the tortoises to live in different environments.

13. Darwin’s Finches

14. Darwin’s Finches
Among the different islands he noticed a variety of beak shapes and sizes.
Some finches had heavy, short beaks useful for pecking trees or seeds, while others had small, thin beaks that could be used for capturing insects.
These observations cause Darwin to wonder if the birds had evolved from similar species.

16. Bird's Beaks

17. How did tortoises and birds differ among the islands of the Galapagos?
competitive exclusion = adaptation = speciation
Each island had its own type of tortoises and birds that were clearly different from other islands

18. SPECIATION The Formation of A New Species:
portion of gene pool becomes isolated; process of generating new species
the accumulation of changes may separate a population into distinct groups

19. Speciation

20. These squirrels live on opposite sides of the Grand Canyon.
This is an example of geographic speciation.

21. Speciation in Darwin’s Finches
Speciation in the Galapagos occurred by:
- Geographic Isolation
which led to
- Reproductive Isolation
and
- Changes in the gene pool
driven by
- Competition.

22. Natural Selection

23. Natural Selection
Natural Selection: This is a process by which members of a species that are best suited to their environment survive and reproduce at a higher rate than other members of species
“Survival of the fittest.”

24. Natural Selection overproduction variation adaptation selection
Darwin came up with this theory of Natural Selection based on 4 key principles:
overproduction
variation
adaptation
selection

25. Principles of Natural Selection
Overproduction:
When a plant or animal reproduces, it usually makes more offspring than the environment can support

26. Principles of Natural Selection
Variation:
Within a species there are natural differences in traits among individuals

27. Principles of Natural Selection
Mutation:
a change in genetic material causing a new variation to come about which can be passed to the next generation
BrainPOP - Genetic Mutations

28. Principles of Natural Selection
Adaptation:
any inherited trait that gives an organism an advantage in its particular environment

29. Principles of Natural Selection
Individual organisms with a particular adaptation that are most likely to survive long enough to reproduce will pass this adaptation to the next generation.
As this process repeats from generation to generation, more members of a species show the adaptation; the species is evolving over time

30. Artificial Selection
Outside forces guiding selection of desired traits.
Nature provides variation then humans select upon specific variations.
Ex: A farmer breeds only his best livestock

31. Evidence Supporting the Theory of Evolution
A widely accepted statement based on scientific evidence that helps explain a group of facts

32. Evidence Supporting the Theory of Evolution
Biological Evolution
Genetic Evidence
Geological Evolution
Fossil Record

33. Evidence Supporting the Theory of Evolution
Biological (Organic)Evolution:
genetic change in a population of organisms
 the change over time in the proportion of individual organisms differing in one or more inherited traits

34. Biological Evidence Similarities in Structure:
Vestigial Structures:
physical structures that were fully developed and functional in an ancestral group of organisms but are reduced and unused in the later species.
Ex: Snakes have traces of leg-like structures, whales also have small leg-like structures that are not used

35. Biological Evidence Similar Structure, Different Function:
Many species share similar structures but the structures have different functions
Ex: lizards, bats, and manatees have forelimbs that have a similar bone structure but they are all used in different ways

36. Biological Evidence

37. Biological Evidence Similarities in Development
Various animals look similar in their earliest stages of life

38. Biological Evidence

39. Genetic Evidence DNA is the genetic material found in all organisms
DNA contains the information all organisms need to grow and to maintain themselves
When an organism reproduces they pass their DNA on to their offspring

40. Genetic Evidence
Scientists are able to tell how closely organisms are related by comparing their DNA