Big Idea 1: The process of evolution drives the diversity and unity of life. (Chapters 22-25 with biodiversity chapters mixed in.)

Enduring Understanding 1 Enduring Understanding 1.A: Change in the genetic makeup of a population over time is evolution. Natural selection is the major driving mechanism of evolution. Darwin’s theory of natural selection states that inheritable variations occur in individuals in a population. Individuals with more favorable variations or phenotypes are more likely to survive and produce more offspring. How is evolutionary success measured? What is the smallest unit that can evolve?

Fig. 22-5 NORTH AMERICA GREAT BRITAIN EUROPE ATLANTIC OCEAN The Galápagos Islands AFRICA Pinta Genovesa Marchena Equator SOUTH AMERICA Santiago Daphne Islands Pinzón AUSTRALIA Fernandina PACIFIC OCEAN Isabela Santa Cruz Andes Cape of Good Hope Santa Fe San Cristobal Tasmania Florenza Española Cape Horn New Zealand Tierra del Fuego

Essential knowledge 1.A.1: Natural selection is a major mechanism of evolution. Genetic diversity can also be explained by the following. (Note: natural selection is the leading cause of evolution) Mutation Genetic drift: chance and random events (especially in small populations) Sexual selection Artificial selection Absence of migration Human directed processes (transgenic organisms: recombinant DNA) Gene flow

Fig. 23-15 Figure 23.15 Sexual dimorphism and sexual selection

Original population Bottlenecking event Surviving population Fig. 23-9 Figure 23.9 The bottleneck effect Original population Bottlenecking event Surviving population

Toyger: Artificial Selection

Transgenic Organisms

Hardy-Weinberg Maintaining a Hardy Weinberg Equilibrium: Large population size Absence of migration (No gene flow or exchange of alleles) No net mutations Random mating Absence of selection (no natural selection)

Essential knowledge 1.A.2: Natural selection acts on phenotypic variations in populations. Environments change and act as selective mechanisms on populations. Example: Peppered moth or flowering time and global climate change Phenotypic variations are not directed by the environment but occur through random changes in the DNA and through new gene combinations. Heterozygote advantage: Some phenotypic variations significantly increase or decrease fitness of the organism. Example: Sickle Cell Anemia, Peppered moth, DDT resistance in insects. Humans impact variation in other species. Example: Artificial selection or overuse of antibiotics

Frequency of individuals Fig. 23-13 Original population Frequency of individuals Phenotypes (fur color) Original population Evolved population Figure 23.13 Modes of selection (a) Directional selection (b) Disruptive selection (c) Stabilizing selection

Essential knowledge 1.A.3: Evolutionary change is also driven by random processes. Genetic drift is a nonselective process occurring in small populations. Occurs by chance events. Bottleneck effect: Founder effect: Reduction of genetic variation within a given population can increase the differences between populations of the same species. Example: Albinism in an Indian tribe or Huntington’s disease within a specific area in South America.

Essential knowledge 1.A.4: Biological evolution is supported by specific evidence from many disciplines. Scientific evidence of evolution uses information from geographical, geological, physical, chemical, and mathematical applications. Fossils: Age of rock where fossil is found and rate of decay of isotopes. Homologous structures and vestigial structures. Biochemical and genetic similarities (DNA and protein comparisons). Embryology: Mathematical models and simulations. Example: Phylogenetic trees or allele frequencies

Humerus Radius Ulna Carpals Metacarpals Phalanges Human Cat Whale Bat Fig. 22-17 Humerus Radius Ulna Carpals Metacarpals Phalanges Human Cat Whale Bat

Pharyngeal pouches Post-anal tail Chick embryo (LM) Human embryo Fig. 22-18 Pharyngeal pouches Post-anal tail Chick embryo (LM) Human embryo

Vestigial Structures

Enduring understanding 1 Enduring understanding 1.B: Organisms are linked by lines of descent from common ancestry. Domains of life: Domain Archae, Domain Bacteria, and Domain Eukarya Comparison between prokaryotes and eukaryotes. Elements that are conserved in ALL domains of life: DNA and RNA are carriers of genetic information. Universal genetic code: All codons code for the same amino acids. Similar metabolic pathways. (Example: glycolysis) Phylogenetic trees can model evolutionary history representing both acquired traits and those lost during evolution.

Essential knowledge 1.B.1: Organisms share many conserved core processes and features that evolved and are widely distributed among organisms today. Structural and functional evidence. Relatedness of all eukaryotes: Cytoskeleton: Microtubules, intermediate filaments, and microfilaments. Membrane-bound organelles: Linear chromosomes: Endomembrane system including the nuclear envelope. (ER, Golgi Apparatus, Lysosome, and plasma membrane)

Essential knowledge 1.B.2: Phylogenetic trees and cladograms are graphical representations of evolutionary history that can be tested. Phylogenetic trees and cladograms can represent traits that are either derived or lost due to evolution. Example: Number of heart chambers in animals or absence of legs in some sea mammals. They illustrate speciation that has occurred. Allopatric versus sympatric speciation. Can be constructed from morphological similarities or DNA and protein comparisons. They are constantly being revised based on current and emerging knowledge.

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Homologous characteristic Fig. 22-19 Branch point (common ancestor) Lungfishes 1 Amphibians Tetrapods 2 Mammals Tetrapod limbs Amniotes 3 Lizards and snakes Amnion 4 Crocodiles Homologous characteristic 5 Ostriches Birds 6 Feathers Hawks and other birds

Enduring understanding 1 Enduring understanding 1.C: Life continues to evolve within a changing environment. Speciation and extinction rates vary greatly. Rates can be slow and gradual (gradualism) or occur in rapid bursts followed by quiet periods (punctuated equilibrium). During ecological stress extinction rates are rapid and are often followed by adaptive radiation (the rapid evolution of species when new habitats open). A species is defined as a group of individuals capable of interbreeding and exchanging genetic information to produce viable, fertile offspring.

Essential knowledge 1.C.2: Speciation may occur when two populations become reproductively isolated from each other. Allopatric speciation: A geographical barrier prevents gene flow and as a result two new species result. Example: Pre and post zygotic mechanisms. Sympatric speciation: A new species evolves within the parent population. Example: Plants and their ability to be polyploidy.

Fig. 24-4a Prezygotic barriers Habitat Isolation Temporal Isolation Behavioral Isolation Mechanical Isolation Individuals of different species Mating attempt (a) (c) (e) (f) (d) Figure 24.4 Reproductive barriers (b)

Reduced Hybrid Viability Reduced Hybrid Fertility Hybrid Breakdown Fig. 24-4i Prezygotic barriers Postzygotic barriers Gametic Isolation Reduced Hybrid Viability Reduced Hybrid Fertility Hybrid Breakdown Viable, fertile offspring Fertilization (g) (h) (i) (l) (j) Figure 24.4 Reproductive barriers (k)

Essential knowledge 1.C.3: Populations of organisms continue to evolve. Examples: Chemical resistance. Emergent diseases. Directional phenotypic changes in a population (Darwin’s finches). Evolution of a structure or process (heart chambers).

Enduring Understanding 1 Enduring Understanding 1.D: The origin of living systems is explained by natural processes. One hypothesis suggests that early Earth provided inorganic precursors from which organic molecules could have been synthesized due to the availability of free energy and the absence of a significant amount of oxygen. (organic soup model) Other hypotheses suggest that these reactions occurred on solid reactive surfaces such as clay. RNA may have been the earliest genetic material. (siRNA has a direct effect on protein synthesis) These organic molecules became the monomers to form polymers (macromolecules).

Essential knowledge 1.D.2: Scientific evidence from many different disciplines supports models of the origins of life. Earth formed approximately 4.6 billion years ago. Environment was too hostile until 3.9 bya. Earliest fossil evidence was 3.5 bya. Experiments suggest that it is possible to form complex organic materials from inorganic molecules in the absence of life.