L3 - Decent with Modification 2025 PDF

Evolution – Decent with modification Read: Chapter 22 Mastering Biology – Chapter 22  Quiz 1 (L2-3) Due Wednesday, January 15th midnight  Key Concepts What was the intellectual climate in the early 1800’s? Who was Charles Darwin? Which observations led...

Evolution – Decent with modification Read: Chapter 22 Mastering Biology – Chapter 22  Quiz 1 (L2-3) Due Wednesday, January 15th midnight  Key Concepts What was the intellectual climate in the early 1800’s? Who was Charles Darwin? Which observations led Darwin to his theory on “Descent with Modification”? Which observations led Darwin to formulate his evolutionary mechanism – natural selection?  Evolution is associated with Darwin but many others contributed to the ideas Muslim evolutionary thinkers: D2L link  Evolution is associated with Darwin but many others contributed to the ideas Muslim evolutionary thinkers: D2L link  Aristotle (384-322 B.C.) Scala naturae: classified on scale of increasing complexity – Species are perfect and permanent  Carolus Linnaeus Father of Modern Taxonomy - 1758 – Grouped species into hierarchy of increasingly general categories based on similarity – Binomial naming system (e.g. Homo sapiens) Jean Baptiste de Lamarck Father of Evolutionary Theory - 1809 Compared extant & fossil species and recognized lines of descent (= evolutionary change) – Simple organisms continually generated, become better adapted to environment & previous form goes extinct  Jean Baptiste de Lamarck (1744-1829) (cont’d) Mechanism: inherent drive to become more complex – “Use and disuse”: used body parts become larger & stronger, others deteriorate – “Inheritance of acquired traits”: modifications acquired during lifetime passed to offspring  George Cuvier Father of Paleontology – 1812 – History of life in fossil-containing strata – Older = more divergent from extant species – Extinction is common – New species appear in successive strata Figure 22.3  George Cuvier (cont’d) Earth is too young for evolution to occur Catastrophism: – Strata boundaries correspond to catastrophic events – Local extinction of species – Inward migration of new species in subsequent strata  Charles Darwin 1809-1882 Medical school in Edinburgh Cambridge to become clergyman Darwin recommended to Captain FitzRoy to ‘serve as naturalist’ on the HMS Beagle for a worldwide voyage The seven-year-old Charles Darwin in 1816 (wikipedia).  Charles Darwin (cont’d) Figure 22.5 HMS Beagle – 1831-1836 Species had adaptations (heritable traits) that suited them to their environment Temperate S.A. species related to tropical S.A. species, not temperate European species S.A. fossils resembled S.A. extant species, not European fossils  Charles Darwin (cont’d) Galápagos Islands – Volcanic craters and recent lava (new!) – Islands with unique species related to species on other islands & from mainland S.A. – “the first appearance of new beings on this earth” (Darwin’s autobiography) – Descent with modification Richard Dawkins: Saddles and Domes: Evolution of the Giant Tortoises  Charles Darwin (cont’d) Figure 22.9 Artificial selection: “I soon perceived that selection was the keystone of man's success in making useful races of animals and plants.” (Darwin’s autobiography)  Descent with Modification: A Darwinian View of Life THINK-PAIR-SHARE Why might organisms that have been artificially selected be less fit?  Natural Selection Mechanism - Observations: –Members of a population vary in heritable traits –Organisms produce more offspring than the environment can support; many fail to survive and reproduce  Natural Selection (cont’d) Inferences: –Individuals whose inherited traits give them a higher probability of surviving and reproducing leave more offspring –Unequal survival and reproduction leads to the accumulation of favorable traits –‘Natural Selection’  Charles Darwin Published (1859): On the Origin of Species by Means of Natural Selection 1) ‘Descent with Modification’ - species were not created in their present form, but have evolved from ancestral species 2) ‘Natural Selection’ is the evolutionary mechanism for evolution “The Origin of Species was truly radical; not only did it challenge prevailing scientific views, it also shook the deepest roots of Western culture.” Darwin was fully aware of this fact!!! http://www.pbs.org/wgbh/nova/evolution/darwi ns-darkest-hour.html  Darwin in an Intellectual/Temporal Context ~1758 Linnaeus Hierarchical Classification Figure 22.2  (binomial) Species Genera Family Darwin: pictured a tree of life from the Linnaean system of classification  1. Reproduction 2. Variation in traits (differences Evolution Evolution in phenotypes) by natural by natural 3. Trait differences are heritable (genetic basis) selection selection 4. Variation in fitness (not all requires: requires: individuals succeed) and this variation is related to trait differences YouTube: Natural Selection Natural selection: differential survival/reproduction based on variation in inherited traits Key Features of Natural Selection Individuals with certain heritable characteristics survive and reproduce at a higher rate than other individuals Natural selection increases the adaptation of organisms to their environment over time If an environment changes over time, natural selection may result in adaptation to the new conditions, which may give rise to new species Can we have evolution YES!! BUT there is no adaptive evolution without natural selection without Random chance can mean that some genes/inherited natural traits/etc are lost from populations selection?  Evolution in biology is the change in populations over time, not individuals natural selection does not equal competition  The Evidence for Evolution is Overwhelming Examples of evolution by natural selection are known in nature Text example of “Host race radiation in soapberry bug” Drug resistance in bacteria Homology of features among different organisms Fossil record shows a progression of species through time Ray Troll Cruisin the Fossil Freeway Biogeographical patterns of species distribution Youtube: Evidence for Evolution  The Evidence for Evolution is Overwhelming Examples of evolution by natural selection are known in nature Text example of “Host race radiation in soapberry bug” Drug resistance in bacteria Homology of features among different organisms Fossil record shows a progression of species through time Ray Troll Cruisin the Fossil Freeway Biogeographical patterns of species distribution Youtube: Evidence for Evolution  The Evidence for Evolution is Overwhelming Examples of evolution by natural selection are known in nature Text example of “Host race radiation in soapberry bug” Drug resistance in bacteria Homology of features among different organisms Fossil record shows a progression of species through time Ray Troll Cruisin the Fossil Freeway Biogeographical patterns of species distribution Youtube: Evidence for Evolution Drug resistance in bacteria  The Evidence for Evolution is Overwhelming Examples of evolution by natural selection are known in nature Text example of “Host race radiation in soapberry bug” Drug resistance in bacteria Homology of features among different organisms Fossil record shows a progression of species through time Ray Troll Cruisin the Fossil Freeway Biogeographical patterns of species distribution Youtube: Evidence for Evolution  Homology Homology is similarity resulting from common ancestry Homologies are traits present in two or more organisms that were inherited from their common ancestor Anatomical/structural homologies Developmental homologies Genetic homologies  Anatomical and Molecular Homologies Homologous structures are anatomical resemblances representing variations on a structural theme present in a common ancestor Figure 22.15 Mammalian forelimbs: homologous structures.  Anatomical and Molecular Homologies Comparative embryology reveals anatomical homologies not visible in adult organisms – For example, all vertebrate embryos have a post-anal tail and pharyngeal arches Figure 22.16 Anatomical similarities in vertebrate embryos.  Developmental homologies Developmental similarities between organisms during early embryonic stages (due to inheritance of developmental processes from a common ancestor) Slide credit: Lynn Norman  Developmental homologies Developmental similarities between organisms during early embryonic stages (due to inheritance of developmental processes from a common ancestor) Which individual is a human: A, B, C, D, or E? Slide credit: Lynn Norman Anatomical and Molecular Homologies Vestigial structures are remnants of features that served important functions in the organism’s ancestors Anatomical and Molecular Homologies Examples of homologies at molecular level are genes shared among organisms inherited from a common ancestor Humans & Chimpanzee Humans & Mouse DNA is about 99% the protein coding regions same 85% identical Anatomical and Molecular Homologies All living taxa are made of cells Basic chemical building blocks are common to all cells (e.g. amino acids, proteins, nucleotides) Universality of DNA as the genetic code Universal flow of biological information, DNA to RNA to amino acids/proteins  Homologies and “Tree Thinking” Evolutionary trees are hypotheses about relationships among different groups Homologies form nested patterns in evolutionary trees Evolutionary trees can be made using different types of data, for example, anatomical and DNA sequence data Tree Thinking Copyright © 2025 Pearson Canada, Inc. 22 - 48  A Different Cause of Resemblance: Convergent Evolution Convergent evolution is the evolution of similar, or analogous, features in distantly related groups Analogous traits arise when groups independently adapt to similar environments in similar ways Convergent evolution does not provide information about ancestry  An Example of Convergent Evolution Figure 22.18 Convergent evolution. Copyright © 2025 Pearson Canada, Inc. 22 - 50  The Evidence for Evolution is Overwhelming Examples of evolution by natural selection are known in nature Text example of “Host race radiation in soapberry bug” Drug resistance in bacteria Homology of features among different organisms Fossil record shows a progression of species through time Ray Troll Cruisin the Fossil Freeway Biogeographical patterns of species distribution Youtube: Evidence for Evolution  The Fossil Record Fossil record provides evidence of: – The extinction of species – The origin of new groups – Changes within groups over time  The Transition to Life in the Sea Fossils can document important transitions – For example, the transition from land to sea in ancestors of cetaceans Figure 22.20 The transition to life in the sea.  The Evidence for Evolution is Overwhelming Examples of evolution by natural selection are known in nature Text example of “Host race radiation in soapberry bug” Drug resistance in bacteria Homology of features among different organisms Fossil record shows a progression of species through time Ray Troll Cruisin the Fossil Freeway Biogeographical patterns of species distribution Youtube: Evidence for Evolution  Biogeography Biogeography, the study of the geographic distribution of species, provides evidence of evolution Earth’s continents were formerly united as single large continent (Pangaea), but separated by continental drift An understanding of continent movement and modern species distribution allows us to predict when and where different groups evolved Copyright © 2025 Pearson Canada, Inc. 22 - 56 Biogeography  FOR NEXT CLASS READ Chapter 23 ***Review genotypes, phenotypes, alleles & mutation before next class!***