Exam 4 Study Guide Key PDF

Exam 4 Study Guide Chapter 11 Biological evolution- process by which organisms change over generations through variations in traits and natural selection Nonevolutionary changes are due to short-term environmental changes and are not genetic Theory of common descent-...

Exam 4 Study Guide Chapter 11 Biological evolution- process by which organisms change over generations through variations in traits and natural selection Nonevolutionary changes are due to short-term environmental changes and are not genetic Theory of common descent- theory that all living organisms share a common ancestor Phylogenetic trees illustrate how different species are related through one common ancestor o Branches represent :evolutionary changes o Point where branches represent: common ancestors What experiences influenced Darwin’s theory of evolution? Collection of diverse animals and plants Principles of Geology Divergence between island organisms and mainland species Linnean system is based on shared traits and evolutionary relationships and shows how organisms share common ancestors. Domain: eukarya Kingdom: animalia Phylum: chordata Class: mammalia Order: primates Family: hominidae Genus: homo Species: homo sapiens Anatomical homology- similarities in skeletal bone structures Convergent evolution- structural similarities in unrelated species with relevant lifestyles Vestigial traits- nonfunctional or greatly reduced traits Developmental homologies- similarities in developmental processes from fertilized egg to adulthood Molecular homologies- similarities in DNA sequences Embryonic development Biogeography- the distribution of species on Earth Fossil record: Radiometric dating- ratios of radioactive elements to daughter products are used to estimate the age of rocks Provide direct evidence of change in organisms over time Why is the theory of evolution the best explanation for the origin of humans and other organisms? Good explanation of a wide variety of observations Well-supported by a wide variety of evidence o Anatomy o Geology o Molecular biology o Genetics Demonstrates consilience- agreement among observations from different sources Chapter 12 *use the Natural Selection Worksheet* Chapter 13 Biological species- a group of individuals that can interbreed and produce fertile offspring, cannot reproduce fertile offspring with members of other species  difficult to apply to fossils or organisms who asexually reproduce Reproductive isolation- prevention of gene flow between species prefertilization barriers- prevents fertilization from occurring o spatial reproductive isolation- individuals from different species do not come in contact with each other o behavioral reproductive isolation- ritual behaviors that prepare partners for mating are different in different species o mechanical reproductive isolation- sex organs are incompatible between different species, so sperm cannot reach egg o temporal reproductive isolation- timing of readiness to reproduce is different in different species o Gamete incompatibility- proteins on egg that allow sperm binding do not bind with sperm from another species postfertilization barriers- fertilization occurs but hybrids cannot reproduce o hybrid inviability- zygote cannot complete development because genetic instructions are incomplete o hybrid sterility- hybrid organism cannot produce offspring because chromosome number is odd Three steps of speciation- the evolution of one or more species from an ancestral form: isolation of gene pools of populations of the species evolutionary changes in gene pools of populations evolution of reproductive isolation between populations Race (as defined using the geological species concept)- organisms able to interbreed, descended from a common ancestor, and representing independent evolutionary lineage Evidence that modern humans arose in Africa: Humans have less genetic diversity than any other great ape (indicates young species) African populations have greatest genetic diversity (indicates oldest human population)  physical differences between humans arose within about 10,000 generations (not very long) Genetic evidence of race: allele frequencies- the percentage of the gene copies of a particular allele in a population Evidence that human races are not deep biological divisions within the human species: Human races are not isolated Evidence shows more variation within groups than between groups Traits that have become common due to natural selection of specific populations: skin color sickle-cell nose shape Genetic drift- change in allele frequency due to chance Examples of how it results in the evolution of a population: o Founder effect- genetic differences resulting when a small sample of a larger group begins a new population o Bottleneck effect- variant of founder effect; a small subset survives after disaster wipes out most of the population o Chance events- small populations are especially prone to loss of alleles through chance Sexual selection- when a trait influences the likelihood of mating How does it cause evolution? Traits that are chosen are the ones that get passed on to the next generation Assortative mating- preference to mate with someone like self (height, etc.) How does it cause evolution? Influences allele frequencies- traits selected for increase in the future population Chapter 14 Estimated # of species? 1.3 million Why is this number an estimate? There are species that have yet to be discovered- only 20% are known Three major domains: Bacteria- prokaryotes with peptidoglycan Archaea- prokaryotes without peptidoglycan Eukarya- eukaryotic cells Broad overview of the history of life: prokaryotes evolved into more complex eukaryotes Prokaryotes Found anywhere and able to survive extreme conditions Endospores- allow some to resist adverse conditions Endosymbiotic theory- mitochondria and chloroplasts descended from bacteria inside primitive eukaryotes Four major kingdoms of Eukarya: Protista o Mostly single-celled  o Resemble animals, fungi, and plants o Most members are unknown o Some photosynthesize (algae) o Others consume organic molecules and cellulose Animalia o Vertebrates o Invertebrates o Eukaryotic o Multicellular o heterotrophic Fungi o Immobile o Multicellular o Spores o Heterotrophic o Decomposers o Yeast- single celled o mold Plantae o Multicellular o Eukaryotic o Autotrophic o First plants lacked vascular tissue > evolved o Flowering and nonflowering Adaptive radiation- rapid diversification of some species into a large and varied group of descendant species Examples: evolutionary breakthrough group, extinction of competing group Viruses- organic entities that interact with living organisms but are not quite alive Why are they considered nonliving? o cannot maintain homeostasis o Incapable of growth or reproduction without assistance of other organisms How are evolutionary classifications of living organisms created and tested? Phylogeny- evolutionary relationships Cladistic analysis- technique to examine variation in traits of closely related species Tested by fossil examination and patterns of DNA