Week 15 Evolution PDF

Week 15 Evolution Objectives: At the end of this module, you should be able to: 1. describe how natural selection leads to evolution; 2. describe the evidence of evolution; 3. explain how populations of organisms have cha...

Week 15 Evolution Objectives: At the end of this module, you should be able to: 1. describe how natural selection leads to evolution; 2. describe the evidence of evolution; 3. explain how populations of organisms have changed and continue to change over time showing patterns of descent with modification from common ancestors to produce organismal diversity observed today; and 4. describe how the present system of classification of organisms is based on evolutionary relationships. What is Evolution? the cumulative change in a population of organisms over time On the Origin of Species by Means of Natural Selection two main points: (1) All species on Earth are products of descent with modification and (2) Natural selection is the mechanism for descent modification. Evidences of Evolution Evidences of Evolution FOSSIL provide concrete evidence of what organisms GEOGRAPHIC reveal how organisms evolved in their natural RECORDS looked like and how they lived DISTRIBUTION environments Scientists found out that certain layers in the sedimentary rock As Pangaea continued to move and separate into several continents, formation contain fossils that lived for a particular period. the organisms that lived on them were also distributed. Evidences of Evolution COMPARATIVE the study of the similarities and differences in COMMON TRAITS IN EMBRYO ANATOMY the structures of different species Homologous structures among bat, whale, cat, and human Homologous structures are organs that have different functions The similarity in embryonic development of vertebrates includes but have similarities in structures. fishes, birds, mammals. and amphibians can help explain the resemblance of these groups of vertebrates in terms of shared ancestry. Evidences of Evolution GENETIC CHANGES Based on multiple extensive studies conducted by molecular biologists in different parts of the world, the conclusion of human and chimps having 95% or >98% DNA similarities depend on which nucleotides are counted and excluded. How Evolution Works How Evolution Works DIVERGENT EVOLUTION CONVERGENT EVOLUTION occurs when closely related species diverted to new habitats of groups of distantly related lineages tend to evolve similar diverging lifestyles, ultimately producing distinct species structures as adaptations to a similar habitat or way of life How Evolution Works ADAPTIVE RADIATION COEVOLUTION happens when ancestral species invade a new territory with no usually observed in predator-prey relationships, as well as in known competitors, allowing them to exploit the resources of the close relationships like mutualism and competition said environment and occupy a specific niche used to describe the case of two or more nonbreeding species affecting each other’s survival and evolution A sip of nectar enslaves ants to the trees they guard. How Evolution Works PACE OF EVOLUTION How Evolution Works PACE OF EVOLUTION Gradualism shows a steady and slow evolution Punctuated equilibrium of rapid change followed by periods of no change Classification Based on Evolutionary History Classification Based on Evolutionary History Phylogenetic systematics is the field of biology that deals with identifying the evolutionary relationships among the many different kinds of life on Earth, both living (extant) and dead (extinct) Charles Darwin’s drawing of the tree of life Classification Based on Evolutionary History Classification Based on Evolutionary History