1 / 34

Do Now

Do Now. What different ways do these animals use to move about? What traits does each animal have that help it move about as it does?. Unit 5 Evolution. Ch. 15 Darwin’s Theory of Evolution. The Puzzle of Life’s Diversity.

dwayne
Download Presentation

Do Now

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Do Now What different ways do these animals use to move about? What traits does each animal have that help it move about as it does?

  2. Unit 5 Evolution Ch. 15 Darwin’s Theory of Evolution

  3. The Puzzle of Life’s Diversity • Evolution - modern organisms have descended from ancient organisms (change over time) • Theory - a well-supported, testable explanation of phenomena that have occurred in the natural world

  4. Voyage of the Beagle • Charles Darwin contributed most to our understanding of evolution • He made observations & collected evidence that led him to propose a hypothesis about the way life changes over time

  5. Voyage of the Beagle • That hypothesis, now supported by a large amount of evidence, has become the theory of evolution

  6. Darwin’s Observations • Darwin collected the preserved remains of ancient organisms - Fossils • Some of these fossils resembled organisms that were still alive • Others looked unlike any creature ever seen

  7. Darwin’s Observations • The Galapagos Islands influenced Darwin the most • He observed that the characteristics of animals & plants varied among the different Islands

  8. Darwin Presents His Case • Darwin published the results of his work in a book, On the Origin of Species • In his book, he proposed a mechanism for evolution called natural selection • He stated that evolution has been taking place for millions of years, & continues in all living things • Friday “Dangerous Mind” Movie on Darwin (complete worksheet) Remember!!! Reward Friday

  9. Home Work (Monday) • Computer time required at home or library. One page required Choose 1 to write about • Compare Darwin’s and Wallace’s theories. • Compare and contrast both Darwin’s and Wallace’s careers and background. • Genetics Test

  10. An Ancient, Changing Earth • Hutton & Lyell helped scientists recognize that Earth is millions of years old • They also noted that the processes that changed Earth in the past are the same processes that are changing Earth now

  11. Lamarck’s Evolution Hypothesis • The year that Darwin was born, Lamarck published his hypothesis • He proposed that by selective use or disuse of organs, organisms acquired or lost certain traits during their lifetime • Over time, this process led to change in a species

  12. Lamarck’s Explanation

  13. Population Growth • English economist, Malthus, published a book, noting that babies were being born faster than people were dying • He stated that if the human population continued to grow unchecked, sooner or later there would be insufficient living space & food for everyone

  14. Inherited Variation & Artificial Selection • Artificial selection - nature provided the variation, & humans selected those variations that they found useful • It has produced diverse plants & animals by selectively breeding for different traits

  15. Evolution by Natural Selection • Struggle for existence - the members of each species compete regularly to obtain food, living space, & other necessities of life • Predators that are faster & better at catching prey are more likely to survive

  16. Evolution by Natural Selection • Fitness - the ability of the organism to survive & reproduce in its specific environment. • Fitness is the result of adaptations

  17. Evolution by Natural Selection • Adaptation - any inherited characteristic that increases an organisms’ chance of survival • Successful adaptations allow organisms to become better suited to their environ. & thus better able to survive

  18. Evolution by Natural Selection • Individuals that are better suited to their environ., with adaptations that enable fitness, survive & reproduce most successfully - Survival of the Fittest

  19. Evolution by Natural Selection • Since it is similar to artificial selection, Darwin referred to survival of the fittest as - Natural Selection • In both AS & NS, only certain individuals of a population produce new individuals

  20. Evolution by Natural Selection • However, in NS, the traits being selected, & therefore, increasing over time, contribute to an organism’s fitness • NS takes place without human control or direction

  21. Evolution by Natural Selection • NS results in changes in the inherited characteristics of a population, that increase a species’ fitness in its environ. • Over time, NS produces organisms that have different structures, & occupy different habitats

  22. Evolution by Natural Selection • As a result, species today look different from their ancestors • Each living species has descended, with changes, from other species over time - Descent with Modification

  23. Evolution by Natural Selection • Descent with modification also implies that all living organisms are related to each other • Common descent - all species (living & extinct) were derived from common ancestors

  24. Evidence of Evolution • Darwin argued that living things have been evolving on Earth for millions of years • Evidence of this could be found: in the fossil record, the geographical distribution of living species, homologous structures of living organisms, & similarities in early development

  25. Evidence of Evolution • The Fossil Record: • Darwin noticed that the sizes, shapes, & varieties of related organisms preserved in the fossil record, changed over time

  26. Evidence of Evolution • Geographic Distribution of Living Species: • Darwin realized that similar animals in different locations were the product of different lines of evolutionary descent

  27. Evidence of Evolution • Homologous Body Structures: • Homologous structures - structures that have different mature forms but develop from the same embryonic tissues • Not all homologous structures serve important functions • Organs of many animals are so reduced in size that they are just vestiges, or traces, of homologous organs

  28. Homologous Structures

  29. Evidence of Evolution • Homologous Body Structures: • Vestigial organs- may resemble miniature legs, tails, or other structures, a trace of a homologous structure

  30. Evidence of Evolution • Similarities in Early Development: • The early stages or embryos, of many animals with backbones are very similar

  31. Summary of Darwin’s Theory • Individual organisms differ, & some of this variation is heritable • Organisms produce more offspring than can survive, & many that do survive do not reproduce

  32. Summary of Darwin’s Theory • Because more organisms are produced than can survive, they compete for limited resources • Individuals best suited to their environ., survive & reproduce most successfully

  33. Summary of Darwin’s Theory • These organisms pass their heritable traits to their offspring • This process of NS causes species to change over time

  34. Summary of Darwin’s Theory • Species alive today are descended with modification from ancestral species that lived in the distant past • This process, where diverse species evolved from common ancestors, unites all organisms on Earth into a single tree of life

More Related