Theory of Evolution (mechanism of developing)

The theory that organisms today developed from more simple life forms and have changed (evolved) over time.

1. LIBERAL ART of SCIENCES “THEORY OF EVOLUTION” Lecturer : Taalai Mambetov

2. EVOLUTION The theory that organisms today developed from more simple life forms and have changed (evolved) over time.

3. A new era of biology began in 1859 when Charles Darwin published The Origin of Species The Origin of Species focused biologists’ attention on the great diversity of organisms Darwin noted that current species are descendants of ancestral species Evolution can be viewed as both a pattern and a process

4. Charles Darwin 1809 - 1882

5. Scale of discovers

6. Evolution Pre-Darwin Beliefs

7. Evolution Pre-Darwin Beliefs Jean Pierre Lamark believed that organisms can change their traits during their lifetime by use or disuse. He thought that these traits are passed on to offspring. Over time this would cause change in a species.

8. Darwin’s Research As a boy and into adulthood, Charles Darwin had a consuming interest in nature Darwin first studied medicine (unsuccessfully), and then theology at Cambridge University After graduating, he took an unpaid position as naturalist and companion to Captain Robert FitzRoy for a 5-year around the world voyage on the Beagle

9. The Voyage of the Beagle During his travels on the Beagle, Darwin collected specimens of South American plants and animals He observed that fossils resembled living species from the same region, and living species resembled other species from nearby regions His interest in geographic distribution of species was kindled by a stop at the Galápagos Islands west of South America He hypothesized that species from South America had colonized the Galápagos and speciated on the islands

10. Voyage of the Beagle What did Darwin find? The finches on each island in the Galapagos had different types of beaks. (a) Cactus-eater (b) Insect-eater (c) Seed-eater

11. Voyage of the Beagle What did Darwin find? The tortoises on each island in the Galapagos had different types of shells.

12. hypothe s is? Darwin hypothesized that organisms had a common ancestor, but had adapted to their particular environments and changed over time. Darwin published his research in 1859 .

13. Artificial Selection , Evolution and Natural Selection

14. Evolution & Natural Selection Genetic variations are passed on through r eproduction Evidence for evolution illustrates how organisms are related Natural selection leads to evolution Our understanding of evolution has changed over time

15. Artificial Selection Darwin noted that humans have modified other species by selecting and breeding individuals with desired traits, a process called artificial selection. Darwin drew two inferences from two observations:

16. Observation #1: Members of a population often vary in their inherited traits

17. Spore cloud Observation #2: All species can produce more offspring than the environment can support, and many of these offspring fail to survive and reproduce

18. Natural Selection The theory that states that those organisms best adapted to their environment have a better chance of surviving and reproducing.

19. Natural Selection For natura l selection t o occur, there must be at least two varieties of a species. For example: the peppered moth

20. Peppered Moths At the beginning of the Industrial Revolution in England, coal burning produced soot that covered the countryside in many areas

21. What do you think happened?

22. Evolution/Natural Selection White moths became easier to see, while the black moths became harder to see. The black moths were more likely to survive and pass on the gene for dark color to their offspring. Over time, the black moths have become more.

23. (a) A flower mantid in Malaysia (b) A leaf mantid in Borneo

24. Evidence for Evolution: Common Ancestry

25. Evidence for Evolution: Homologous Structures

26. Evidence for e volution : Embryo Development What do you notice?

27. Evidence for Evolution: Vestigial Organs Some organisms have structures or organs that no longer have a useful function. These structures or organs may have been useful to the ancestors of a species, but over time have evolved into what we term vestigial organs.

28. Examples of Vestigial Organs Kiwi (flightless bird) Whales (hind leg bones) Humans (tailbone, appendix)

29. Evidence for Evolution Fossils Fossils provide a look into the past . Scientists can trace how a species has evolved by studying fossils .

30. Wrap Up the Evidence