(●̮̮̃•̃) /█\ .Π. ~Sir Zybs

1. Evidences of Evolution FOSSIL RECORD, MORPHOLOGY, EMBRYOLOGY, AND BIOCHEMISTRY

2. Fossil Record Fossil – preserved remains of animal or plant. We have to take note that the fossil record will never be complete. Why? Because geologic events obliterated much of it. 1. The rest of the record is slanted toward species that has hard parts, 2. has dense populations with wide distribution, 3. And had persisted for a long time. Although the fossil record is substantial enough to help us reconstruct patterns and trends in the history of life.

3. Fossil Record Types of Fossil 1. Compression fossil It is an original part of an organism that was buried under sediments and the water squeezed out of it. E.g. Thin film of plant cuticle that remained from a leaf. 2. Fossil fuels Carbon-containing fuel derived from the decomposed remains of prehistoric plants and animals. a. Coal b. Oil c. Natural Gas

4. Fossil Record 3. Impression Fossil An outline that is formed when hard parts of a dead organism pressed against soft sediment, which then hardened after the organism decayed. E.g. A. Foot prints B. Worm borings 4. Casts Fossil formed when minerals slowly replace tissue. E.g. Long horn coral

5. Fossil Record 5. Mold Impression that is left in rocks. A. Internal Mold B. External Mold E.g. Shell 6. Mineralized Fossils Minerals replaced cells and intracellular materials. E.g. Bones and teeth

6. Fossil Record 7. Petrified Fossils Crystallization of minerals inside cells. E.g. Petrified wood

7. MORPHOLOGICAL EVIDENCE OF EVOLUTION Morphology – the form and structure of an organism or of a part of an organism. Do similar parts indicate an evolutionary relationship? In Morphological Divergence, a body part inherited from a common ancestor becomes modified differently in different lines of descent. Such parts are called homologous structures.

8. Morphological Divergence Among Vertebrate Forelimbs.

9. MORPHOLOGICAL EVIDENCE OF EVOLUTION Homologous structures Similar body parts that reflect shared ancestry. Structures may be used for different purposes in different groups, but the same genes direct their development.

10. MORPHOLOGICAL EVIDENCE OF EVOLUTION Morphological Divergence Refers to a change from the body form of a common ancestor in a macroevolutionary pattern . Macroevolution Evolutionary patterns on a larger scale. Comprises large-scale patterns of evolutionary change such as adaptive radiations, the origins of major groups and loss through extinction.

11. MORPHOLOGICAL EVIDENCE Even though vertebrate forelimbs are not the same in size, shape or function from one group to the next, They are alike in the structure and positioning of bony elements.

12. MORPHOLOGICAL CONVERGENCE In morphological convergence, body parts that appear alike evolve independently in different lineages, not in a common ancestor. Such parts are called analogous structures.

13. Morphological Convergence

14. ANALOGOUS STRUCTURES Structures that look alike in different lineages but did not evolve in a shared ancestor. E.g. Bird wing – flight – feathers Bat wing – flight – skin membrane Insect wing – flight - sac

15. EMBRYOLOGICAL EVIDENCE OF EVOLUTION Embryology Branch of biology dealing with the development of the animal embryo. Development of the fertilized egg and embryo and the growth of fetus.

16. EMBRYOLOGICAL EVIDENCE OF EVOLUTION Developmental Comparisons in Animals Embryos of many vertebrate species develop in similar ways. Their tissues form the same way as embryonic cells divide, differentiate and interact. All vertebrates go through a stage in which they have four limb buds and a tail. Adult forms of these lineages are different. Why do they differ? Answer lies with the heritable changes or the onset, rate or completion of early steps in development. An altered body plan is advantageous.

17. EMBRYOLOGICAL EVIDENCE OF EVOLUTION Body appendages Buds form whenever homeotic gene Dlx is expressed. Dlx gene Encodes a transcription factor that signals clusters of embryonic cells to “srtick out from the body” and give rise to an appendage. Hox gene Help sculpt details of the bodies form. It suppresses Dlx expression in all parts of an embryo that will not have appendages.

18. Dlx/Hox gene control system operates across many phyla. A strong evidence that it evolved a very long time ago. Dlx came first in some Cambrian fossils. Hox appeared later.

19. Comparative Embryology

20. Amino Acid Sequence Similarities

21. Amino Acid Sequence Similarities Are a Measure of Evolutionary Relatedness

22. The Rate of DNA hybridization reflects the degree of evolutionary relatedness.