Transcript Evolution
Evolution • Evolution is the change in genes in a population over time • Evolution helps us understand the history of life • Present-day species evolved from earlier species What is a population? Members of the same species living in a certain location at a specific time Evolution does NOT take place in an individual The changes in the genes (sections of DNA) must be passed on to another generation Types of evidence used to support the Theory of Evolution: A. B. C. D. E. Biogeography The Fossil Record Embryology Comparative Anatomy Biochemical Analysis Biogeography • The study of where species are located on the Earth • Organisms change over time due to environmental changes/stresses A. Biogeography Organisms found on islands share features with species on the mainland – Galapagos Islands • Finch birds • Tortoises Islands with similar environments have similar species Adaptations Organisms change over time due to environmental stresses Three types of adaptations: • Structural • Behavioral • Physiological/function B. Fossil Record Paleontologists study records Fossil records reveal the chronological order of vertebrates is: 1. 2. 3. 4. 5. FISH first appeared on Earth then came… AMPHIBIANS REPTILES BIRDS MAMMALS Types of fossils • • • • • • Imprint Mold Casts Petrified samples Frozen samples Amber—sap from trees C. Comparative Embryology • Study of early stages of development before birth Timing of stages and new features reveals evolution/history of ancestors • New features in different organisms came from the remodeling of ancestral structures Examples: – jaws and inner ears develop from gill slits Gill slits in red Gills still present in fish and some salamanders Embryology and Fossils • Snakes have legged ancestors – Some species have hind (rear) limb buds as early embryos – They lose the buds and develop into legless adults – Fossil evidence of snakes with hind limbs exists – Suggests snakes evolved from a limbed ancestor D. Comparative Anatomy Do birds have phalanges? Do cats have lumbar vertebrae? Do frogs have a humerus bone? Scientists study homologous, analogous, and vestigial structures to show evolutionary relationships Homologous Structures – Share the same pattern of structure—arm bones – Have a recent common ancestor – Come from the same part of the embryo – May or may not perform the same function Analogous Structures – Body part different in structure such as wings – Share a different origin and development – Yet similar in function Vestigial Structures Fully developed in some organisms, yet reduced or functionless in others Examples: – Hip bones in snakes and hip bones in humans – Eyes in blind cave fish E. Biochemical analysis Molecular level living things are very similar • DNA/RNA code • proteins for building blocks • ATP for energy • sugars for fuel • genes for traits Biochemical analysis --Protein synthesis follows the same process in eukaryotes DNARNARibosomesProteins --Roundworms share 25% of their genes with humans Biochemical analysis Examples: --Insulin may control sugar levels in numerous species --Animal cells and plant cells use glucose for making energy Evolutionary pattern of the Animal Kingdom ProtocellsProkaryotesEukaryotes ProtistsInvertebratesVertebrates Evolution Review • What is the definition of evolution? • What are the types of evidence for evolution? • Describe (explain and provide examples) of each type of evidence. • What is the evolutionary pattern for members of the animal kingdom? • Organisms are grouped based on_____? Classification of organisms • Organisms are • The study of grouped based on classification is similarities such called taxonomy phenotypes and evolutionary history