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What do you notice?.

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Presentation on theme: "What do you notice?."— Presentation transcript:

1 What do you notice?

2 What do you notice?

3 What do you noticed?

4 What do you notice?

5 ______________________of Evidence for the Theory of Evolution

6 1.____________ Evidence of Evolution
Fossils Rock fossils are created when three events occur organism buried in sediment calcium in bone or other hard tissue mineralizes surrounding sediment hardens to form rock

7 Fossil Evidence of Evolution
Absolute dating: Relative dating: Isotopes, like U238, transform at precisely known rates into nonradioactive forms. The rate of decay is known as an isotope’s half-life

8 Fossil Evidence of Evolution
Radioactive Decay

9 Fossil Evidence of Evolution
records document the course of life through time

10 Fossil Evidence of Evolution
Fossils The oldest known bird fossil is the It is intermediate between bird and dinosaur Possesses some ancestral traits and some traits of present day birds Archaeopteryx was first found in 1859

11 Fossil Evidence of Evolution
Fossil of Archaeopteryx

12 Fossil Evidence of Evolution
Recent discoveries Four-legged aquatic mammal Important link in the evolution of whales and dolphins from land-dwelling, hoofed ancestors Fossil snake with legs Tiktaalik: a species that bridged the gap between fish and the first amphibian Oysters: small curved shells to large flat shells

13 Fossil Evidence of Evolution
Whale “missing links”

14 Fossil Evidence of Evolution
Evolutionary change in body size and toe reduction of horses

15 HOMOLOGOUS STRUCTURE Similar features that originate in a shared ancestor (derive from same embryonic structure) Can result from modifications that change an original feature to 2 extremely different types (wing and arm) Homologous structures

16 Anatomical Evidence for Evolution
2. Homologous structures: structures with common evolutionary origins (can be similar in structure, function, or both) The bones in the forelimb of mammals are homologous structures Different functions, same ancestor structure

17 Anatomical Evidence for Evolution
Homology of the bones of the forelimb of mammals

18 ANALAGOUS FEATURE Serve identical functions and look similar
No anatomical/embryological similarity Wing developed independently and differently in more-recent ancestors of each animal 3. Analogous structures:

19 Anatomical Evidence for Evolution
Vestigial structures: Vestigial structures of a whale: hind leg bones!?

20 4. Vestigial Structures Humans
Muscles for wiggling ears (similar muscles that animals use to move ears to hear predators or prey) Tail bones present in human and all vertebrate embryos. In humans, the tail is reduced; most adults only have three to five tiny tail bones and, occasionally, a trace of a tail-extending muscle. Appendix Structure which presumably had a digestive function in some of our ancestors, like the cecum of some herbivores. In humans, it varies in length from 5–15 cm, and some people are born without one.

21 Vestigial Structures cont.
Wisdom teeth There are two possible reasons why the wisdom teeth have become vestigial. The first is that the human jaw has become smaller than its ancestors -and the wisdom teeth are trying to grow into a jaw that is much too small. The second reason may have to do with dental hygiene. A few thousand years ago, it might be common for an 18 year old man to have lost several, probably most, of his teeth, and the incoming wisdom teeth would prove useful. Now that humans brush their teeth twice a day, it's possible to keep one's teeth for a lifetime. The drawback is that the wisdom teeth still want to come in, and when they do, they usually need to be extracted to prevent any serious pain.

22 Vestigial Structures cont.
Pythons have tiny femurs (leg bone) Manatees Fingernails on their fins Blind cave fish Nonfunctional eyes

23 Anatomical Evidence for Evolution
Strongest anatomical evidence supporting evolution comes from comparisons of how organisms develop. Early vertebrate embryos possess pharyngeal pouches (gill slits) that develop into: In humans: glands and ducts In fish: gills

24 5. ________________ Evidence for Evolution
Developmental similarities reflect descent from a common ancestor


26 6. All Two closely-related organisms will have similar DNA, RNA, and protein (amino acid) sequences. This also gives evidence of a common ancestor.

27 Convergent Evolution Biogeography: the study of the geographic distribution of species Some plants and animals have similar appearance but are only distantly related Convergent evolution: the independent development of similar structures in organisms that are not directly related Convergent evolution is usually seen in animals and plants that live in similar environments

28 Convergent Evolution Marsupials and placentals
Marsupials: young are born in an immature condition and held in a pouch until they develop Placentals: young are not born until they can safely survive in the external environment

29 Convergent Evolution

30 Convergence among fast-swimming predators
Convergent Evolution Convergence among fast-swimming predators

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