Bio 2 Plant and Animal Biology
Evolution Evolution as the explanation for life s unity and diversity
Darwinian Revolution Two main Points Descent with Modification Natural Selection
Biological Species A group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring
Two Patterns of Evolutionary Change Anagenesis Cladogenesis
Allopatric Speciation
Evidence of Allopatric Speciation
Allopatric Speciation
Allopatric Speciation 1. Small Population 2. Isolation 3. Different Environmental Conditions
Sympatric Speciation Autopolyploidy Examples: Maidenhair Fern Bufo pewzowi 2n 2n=6 Cell division error Tetraploid Cell 4n=12 2n Gametes produced by Tetraploid New Species (4n)
Sympatric Speciation Allopolyploidy Examples: Triticum aestivum Gray Treefrog
Hybrid Zone
Hybrid Zone
Hybrid Zone Over time Reinforcement Strengthening of reproductive barriers Fusion Weakening of reproductive barriers Stability Continued production of hybrid individuals
Adaptive Radiation The emergence of numerous species from a common ancestor introduced into an environment, presenting a diversity of new opportunities and problems
Adaptive Radiation (Silversword Alliance - Tarweed)
Punctuated Equilibrium Macroevolution: Evolutionary Change on a Grand Scale Time Gradualism
Also called Neodarwinism Small changes over time Supporter: Ernst Mayr Gradualism
Punctuated Equilibrium Supporters: Niles Eldredge & Stephen J. Gould Speciation occurs in episodic events large periods of time with little change and short periods of time with large changes
Macroevolution through many Speciation Events
Macroevolution through many Speciation Events Evolutionary Novelties Evolution of Genes that control development Changes in Spatial Pattern Changes in Rate and Timing
Origin of Evolutionary Most novelties are modified versions of older structures Exaptation - preadaptation Novelty
Evolution of Genes that Control Development Julian Huxley - Modern Synthesis Gradual evolution can be explained by small genetic changes that produce variation which is acted upon by natural selection
Evolution of Genes that Control Development Julian Huxley - Modern Synthesis The evolution at higher taxonomic levels and of greater magnitude can be explained by long periods of time
Evolution of Genes that control Forms change Natural Selection is the force driving change How did it occur? Development
Evolution of Genes that control Development Evo-devo How does it occur?
Evolution of Genes that control Evo-devo - Tool-kit of master genes Development
Changes in Spatial Pattern Homeotic Genes (Hox Genes) position information
Changes in Spatial Pattern
Changes in Spatial Pattern Homeobox
Changes in Spatial Pattern Changes in expression patterns of four Hox genes over time
Changes in Rate and Timing Allometric Growth the variation in the relative rates of growth of various parts of the body
Changes in rate and timing Heterochrony - evolutionary change in the timing or rate of development
Changes in rate and timing Paedeomorphosis - retention of juvenile features in an adult
Changes in rate and timing Paedeogenesis - sexual maturity in a larval form
Evolutionary trends are not goal oriented Evolutionary Trends
The Tree of Life Biological Diversity
The Fossil Record
The Fossil Record
The Fossil Record Sedimentary Rocks Hard Parts
The Fossil Record Minerals replacing organic material Organic Material
The Fossil Record Casts Trace Fossils
The Fossil Record Entire Organisms
Dating Fossils Absolute Dating (half-life)
Relative Dating Precambrian (Archaean) Origin of Earth (4.6 bya) Oldest known rocks on Earth s surface (3.8 bya)
History of the Earth Precambrian (Archaean) Oldest Prokaryotes (3.5 bya)
History of the Earth Precambrian (Archaean) Oxygen (2.7 bya)
Precambrian (Proterozoic) Oldest Eukaryotes (1.8 bya) Diversification of Multicellular Eukaryotes (542-635 mya)
Paleozoic Era - Cambrian Period (488 542 mya) Cambrian Explosion - Origin of most modern animal phyla
Paleozoic Era - Ordovician Period (488 444 mya) Origin of land plants First arthropods on land First jawless fish First Fungi
Paleozoic Era - Silurian Period (444 416) First jawed fish First vascular plants Diversity of early vascular plants
Paleozoic Era - Devonian Period (416 359 mya) Age of Fishes First Amphibians First Insects
Paleozoic Era - Carboniferous Period (359 299 mya) Vascular Forests First Seed Plants Amphibians Abundant First Reptiles
Paleozoic Era - Permian Period (299 251 mya) Radiation of Reptiles Origin of mammallike Reptiles Most modern orders of insects Largest Extinction
Mesozoic Era - Triassic Period (251 199.6 mya) Gymnosperms dominant Radiation of Dinosaurs First Mammals and Birds
Mesozoic Era - Jurassic Period (199.6 145.5 mya) Dinosaurs Dominate Gymnosperms Dominate
Mesozoic Era - Cretaceous Period (145.5 65.5 mya) Flowering Plants Appear Dinosaurs Disappear at End of Period
Cenozoic Era (Age of Mammals) Quaternary Period (2.6 mya Present) Neogene Period (23 2.6 mya) Paleogene Period (65.5-23 mya)
Paleogene Period - Paleocene Epoch Adaptive Radiation of Mammals, Birds, and Insects
Paleogene Period - Eocene Epoch Angiosperm Dominance Most Modern Mammal Orders
Paleogene Period - Oligocene Epoch First Primates
Neogene Period - Miocene Epoch Continued Radiation of Mammals and Flowering Plants Earliest direct human ancestors
Neogene Period - Pliocene Epoch Bipedal human ancestors appear
Quaternary Period Pleistocene Epoch Ice Ages Homo genus appears
Quaternary Period Recent (Holocene) Epoch Historic Time
Continental Drift and Plate Tectonics
Plate Tectonics
Plate Tectonics
Earth s History Pangaea (245 mya) Pangaea began to break up (180 mya) Laurasia Gondwana
Mass Extinctions Ordovician (440) Devonian (365) Permian (245) Triassic (210) Cretaceous (65)
K-T Boundary Chicxulub Crater - Caribbean Sea near the Yucatan Peninsula of Mexico
Tree of Life
Systematics The study of biological diversity in an evolutionary context
Systematic Tools Molecular Comparisons usually (rrna or mtdna) DNA-DNA Hybridization Restriction maps DNA Sequence analysis
Phylogenetic Groupings Monophyletic ancestor and all its descendants
Phylogenetic Groupings Paraphyletic ancestor with some but not all its descendants
Phylogenetic Groupings Polyphyletic two different ancestors
Phylogenetic Groupings
Similarities Homology likeness attributed to shared ancestry
Similarities Analogy likeness due to similar ecological roles and natural selection due to convergent evolution
Molecular Homoplasy Analogous species that have similar DNA sequences that evolved independently in two species
Ontogeny Recapitulates Phylogeny (Ernst Haeckel) Ontogeny individual development Recapitulates repeats Phylogeny evolutionary descent
The Science of Systematics Phenetics based on a number of similarities and differences does not take into account homology or analogy all groupings
Classical Evolutionary Systematics George Gaylord Simpson
The Science of Phylogenetic Systematics Classical Evolutionary Systematics most commonly used up until recently based on shared homologous structures takes into account the amount of adaptive evolutionary change (novelties) Monophyletic and paraphyletic groupings
The Science of Systematics Cladistics (Phylogenetic Systematics) based on shared homologous structures only monophyletic groupings Will Hennig
The Science of Phylogenetic Systematics Cladistic Assumptions 1. Monophyletic 2. Descent follows a bifurcating pattern 3. Changes in characteristics occur in lineages over time
Cladistics Synapomorphies: Shared derived characters Plesiomorphies: Shared Ancestral or Primitive characters
Phylograms
Ultrametric Trees
Cladistics
Cladistics
Cladistics
Molecular Clock