Adaptation Adaptations are inherited traits that increase a groups chance of survival amp reproduction This type of finch has a thick beak adaptation for cracking open seeds Variation ID: 1042813
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1. EVOLUTIONARY THEORYEvolution= Gradual change over time
2. AdaptationAdaptations are inherited traits that increase a group’s chance of survival & reproductionThis type of finch has a thick beak adaptation for cracking open seeds
3. VariationWithin a species, there is variationVariation = differences between members of a populationSpecies = group that can breed & produce healthy offspring
4. The ScientistsJean Baptist Lamarckvs.Charles Darwin
5. Jean Baptiste Lamarck Evolution occurs as structures develop through use, or disappear because of disuse, and these “acquired characteristics” are passed to offspring.EXAMPLE: Over a giraffes lifetime it can stretch it’s neck and it’s offspring will be born with long necks….Valid?
6. Darwin and The Monkey!THIS IS NOT WHAT HIS THEORY SAYS
7. Who was Charles DarwinStudied medicineHated the sight of bloodReceived a BA in TheologyHad 10 children Darwin was a Naturalist on the HMS Beagle
8. Theory of EvolutionIn The Galapagos Islands, Darwin collected species of finches (13)Each had a specialized diet and beak structureThese finches all closely resembled a South American finch ancestral speciesOn the trip Darwin saw things he could only attribute to a process called:“Natural Selection”
9. Darwin’s Finches
10. Theory of EvolutionHypothesized that the differences were do to gradual changeDarwin referred to such change as “descent with modification” – evolution; Wrote Origin of SpeciesHe still wondered “How does evolution occur?”
11. After his voyage, Darwin made the following inferences:There is variation within populationsSome variations are favorableNot all young produced in each generation can surviveIndividuals that survive and reproduce are those with favorable variationsFavorable traits will increase in future generations.
12. Darwin called this process by which populations change in response to their environment:Natural Selection
13. So....What is Evolution?
14. Evolution happens because of natural selectionSelection acts on individuals, populations evolve
15. Change creates advantages for some species & disadvantages for othersFossils reveal changes in species over millions of years
16. Evidence for EvolutionFossils show change over timescientists can date fossils & use them to support the theory of evolutioncommon ancestors reveal whether species are relatedAnatomy of living species also shows relatedness
17. How Anatomy supports EvolutionHomologous StructuresTraits similar in different species because they share a common ancestorEx: human arm, dog front limb, horse leg, whale finThese “ look the same.” They have the same bones but different function.
18. 3. Analogous structuresDistantly related species have structures that have the same function but are different in structureEx: wing of butterfly & birdThese “ work the same.” They have different bones but the same function.How Anatomy supports Evolution
19. 4. Vestigial structuresStructures reduced in size & often unusedRemains of functional structures inherited from an ancestorEx: leg & hip bones in pythons & whalesHow Anatomy supports Evolution
20. How DNA Supports evolution 5. Molecular EvidenceAlso called biochemical evidenceCompares biomolecules such as DNA or amino acid sequences between organismsRelated organisms have more of the same molecules in common
21. So….. Where Do New Species Come From?
22. How do new species form?Geographic IsolationWhen members of a population are separated Ex: polar, grizzly, & black bears
23. 2. Reproductive IsolationWhen members of a population can’t breed even though they live nearbyEx: different mating seasons or different mating calls
24. Different Types of EvolutionDivergent evolutionConvergent evolutionCoevolutionAdaptive radiation
25. Divergent Evolution-Isolated populations evolve independently Ex: polar & grizzly bears changed independently due to different habitats
26. Convergent Evolution-Unrelated species become more alike because they live in similar environmentsEx: shark & dolphin
27. Coevolution-Species that interact closely adapt to one another Ex: Flowers & Pollinators (Birds, Bees and Butterflies too)
28. Adaptive RadiationEvolution of many diverse species from one common ancestorEx: famous Galapagos finches discovered by Darwin
29. Questions?