BIOL Unit 3 Review PDF

CHAPTER 11- Evidence for evolution Can you define biological evolution, and distinguish it from other forms of non evolutionary change in organisms? Non-evolutionary Biological evolution - Due to short-term environmental - Change in characteris...

CHAPTER 11- Evidence for evolution Can you define biological evolution, and distinguish it from other forms of non evolutionary change in organisms? Non-evolutionary Biological evolution - Due to short-term environmental - Change in characteristics of a changes biological population that occurs - Not genetic over generations - Inherited via genes Can you illustrate the theory of common descent using a tree diagram? - Theory of Common Descent: All life shares a common ancestor Can you summarize how Darwin’s experiences led him to develop the outline of the theory of evolution? - Principles of Geology by Charles Lyell - Alfred Russel Wallace’s manuscript → Detailed mechanism for evolutionary change similar to Darwin’s natural selection - Origins of Species by Means of Natural Selection, of the Preservation of Favoured Races in the Struggle for Life Can you detail the modern biological classification system and explain how it supports the theory of evolution? - Linnaean classification: Organizes biological diversity and implies evolutionary relationships among organisms - Linne: Gave species two-part Latin name, grouped organisms in hierarchy - Classification of humans: Domain- Broader level added in 1990  Can you explain how homologies in anatomy and genetics, even in useless traits, support the theory of evolution? 1. Anatomical homology: Similarities in skeletal bone structures - Equivalent bones found in each organism - Similar structures despite different functions → Mammalian forelimbs - Similarities between chimps and humans 2. Convergent evolution: Structural similarities in unrelated species - No recent common ancestry - Evolution occurred in parallel in different groups 3. Vestigial traits: Nonfunctional or greatly reduced trait - Compare similarities between functional traits in one organism with vestigial traits in others (e.g., flightless birds) - Gametophytes: remains of ancestral relationship with ferns Can you describe how details of embryonic development support the theory of evolution? - Developmental homologies: Similarities in developmental processes from fertilized egg to adulthood Similarities in early chordate embryos - Molecular homologies: Similarities in dna sequences Closely related species have more similar genes - Molecular clock: Estimates the rate of change in DNA sequence Differences in DNA sequences between species determine when divergences from common ancestors occurred Can you define Biogeography and explain how it supports the theory of evolution? - Biogeography: the distribution of species on Earth Unique species of tortoises on each Galapagos Island Resemblances between prickly pear cacti on Islands and the Mainland Evidence of early human ancestors should be close to less-mobile relative in Africa Can you explain how the fossil record provides direct evidence of evolutionary change in species over time? - Fossils: The remains of living organisms left in soil or rock Form a record of ancient life Provide direct evidence of change in organisms over time - Hominins: human and human ancestors Foramen magnum at the base of the skull Modified pelvis and knee Elongated lower limbs relative to front limbs - Differences in fossil structures separate hominids from other primates - Anatomical differences  Chimpanzees are quadrupedal Hominins are bipedal - Radiometric dating: Ratios of radioactive elements to daughter products are used to estimate the age of rocks Radioactive isotopes decay into daughter products Element’s half-life = amount of time required for one-half of the element to decay Can you articulate why the theory of evolution is considered the best explanation for the origin of humans and other organisms? - Only theory supported by a wide range of evidence - Universality of DNA and the relationship between DNA and proteins - Robust theory - Demonstrates consilience: agreement among observations from different sources CHAPTER 12- Natural selection Theories from the Origin of Species: - Theory of common descent All species descended from a single ancestor - Theory of Natural Selection Explains how organisms evolved from a common ancestor Theory of Common Descent: - Most accepted theory - Current species are sequentially evolved from earlier and earlier species - Most compelling evidence is close similarity of DNA between organisms Biological evidence for common ancestry - Linnaean classification - Anatomical homology - Vestigial traits - Developmental homologies - Molecular homology - Biogeography - Fossil record Lamarckian evolution - Organisms have uniform traits but acquire changes in their lifetime to adapt to changes in the environment - Once trait is changed it is permanent and is passed down to future generations - Evolution occurs by successive accumulation of acquired traits  Natural Selection - Organisms have different versions of traits (alleles) and do not acquire inheritable changes in their lifetime to adapt to environment - When environment changes it weeds out undesirable traits and keeps desirable traits → Naturally selects for good traits - Evolution occurs by continuous selection of desirable traits and elimination of unwanted traits Requirements for natural selection - Individuals within populations vary Variation seen in human and non-human populations Variant: each type of individual in a population - Some of the variations among individuals can be passed onto their offspring Darwin observed resemblance between parents and offspring Mendel’s work supported this evolutionary mechanism - Populations of organisms produce more offspring than will survive Even slow-breeding animals can produce large populations quickly - Survival and reproduction are not random Subset of individuals who survive and reproduce is not an arbitrary group Fitness: relative survival and reproduction of one variant Adaptation: traits that increase individual fitness in an environment - Individuals w adaptations for environment = more likely to survive and reproduce - Consequences of Natural Selection - Darwin’s inference: Natural selection causes evolution - Results: Favorable inherited variation increase in frequency Unfavorable variations tend to be lost Evolution: A change in traits of individuals in a population over generations - Testing natural selection: methods to test natural selection as a mechanism for evolutionary change Artificial selection Natural selection in lab Natural selection in wild populations - Adaptations: Changes developed to allow a species to be better equipped to survive in their environment - Subtleties of natural selection Natural selection only acts on traits present in population, not individuals An adaptation may be beneficial in most conditions, but not all Selections  1. Artificial selection: Selection imposed by human choice (ex. Dog breeds) 2. Natural selection in the lab: Environmental conditions can be manipulated (ex. Fruit flies placed in alcohol) 3. Natural selection in wild populations: Examples of evolution (Drug and pesticide resistance in other pathogens) CHAPTER 13- Speciation and Macroevolution Can you define biological species, and list the mechanisms by which reproductive isolation is maintained by biological species? - Biological species: a group of individuals that can interbreed and produce fertile offspring - Cannot reproduce fertile offspring with member of other species - Difficult to apply to fossils or organisms with asexual reproduction - Gene pool: sum total of the alleles found in all individuals of a species - Gene flow: Spread of an allele throughout a species’ gene pool - Reproductive isolation: Prevention of a gene flow between species Two forms of reproductive barriers 1. Prefertilization: Prevents fertilization from occurring - Spatial reproductive isolation - Behavioral reproductive isolation - Mechanical reproductive isolation - Temporal reproductive isolation - Gamete incompatibility 2. Postfertilization: fertilization occurs, but hybrid cannot reproduce - Hybrid inviability - Hybrid sterility Can you describe the three steps in the process of speciation? - Speciation: evolution of one or more species from an ancestral form - THREE STEPS: 1. Isolation of gene pools of populations of the species - Migration: small population becomes isolated in location far from main population - Adaptive radiation: Evolution of several, diversified new species from one founding species - Intrusion of geologic barriers → Slow rise of mountain range, sudden change in river’s course - Allopatric populations: isolated from each other by distance or geographic barrier - Sympatric populations: separated gene pools despite living near each other → reproductively isolated for other reasons - Polyploidy: process of chromosome duplication Allows infertile plant hybrids to become fertile  Cell contain two copies of each chromosome from each parent May occur in insects or frogs - Instantaneous speciation: Polyploid organism is genetically isolated from both parents Key factor in evolution of 50% of flowering plant species 2. Evolutionary changes in gene pools of populations INFORMATION FROM STEP ONE^^^ 3. Evolution of reproductive isolation between populations - Amount of divergence required between two populations is uncertain - Gradualism: slow accumulation of small changes over long period of time; assumed by Darwin - Punctuated equilibrium: Sudden, dramatic changes followed by long periods of little change - Evidence that both processes are at work Can you explain how a “race” within a biological species can be defined using the genealogical species concept? - Species consist of organisms that can interbreed, are all descendants of a common ancestor, and represent independent evolutionary lineages - Most evolutionarily meaningful - Each species has its own unique evolutionary history Can you define genetic drift, and provide examples of how it results in the evolution of a population? - Genetic drift: change in allele frequency that occurs due to chance - Occurs in two different situations: 1. Founder or bottleneck effect: - FE: genetic differences resulting when a small sample of a larger group begins new population - BNE: Variant of founder effect; small subset survives after disaster wipes out most of the population 2. Chance events in small populations - Small populations are especially prone to lose of alleles through chance Can you describe how human and animal behavior can cause evolution via sexual selection and assortative mating? - Sexual selection: when a trait influences the likelihood of mating - Assortative mating: preference to mate with someone like self By height By social factors  Tends to exaggerate physical differences between groups Natural selection since Darwin - The modern synthesis: The union between genetics and evolution; predicted on genetic principles - Genes: segments of genetic material w info about protein structure - Actions of proteins within an organism determine physical traits - Different versions of same gene are alleles, and variation in physical traits is due to variation in alleles - Alleles arise through mutation - Half of alleles carried by parent are passed to offspring through egg/sperm - Patterns of natural selection: different environmental conditions can lead to different changes in populations 1. Directional selection: population traits move in particular direction 2. Stabilizing selection: Extreme variants are selected against and population stabilizes; change is resisted 3. Diversifying selection: Changes in population result in two more variants Human health - Selecting for drug resistance Simple antibiotic treatment can result in directional selection in bacteria Some bacteria more resistant to antibiotic - Stopping drug resistance Maintain drug therapy for months Combination drug therapy Terms - Mutations: Random changes in the genetic makeup of an organism - Genetic Recombination: Gametes uniting during fertilization - Migration: New traits being brought into a population or taking traits out of a population → greatest effect on small populations - Genetic drift: Affects small populations; changes in gene pool due to storms → not significant in large populations CHAPTER 14- Biodiversity Biological classification - Biodiversity: Variety within and among living species - 1.3 million identified species - Extrapolations suggest about 8.7 million species → only 20% known - Estimating biodiversity: extrapolations estimate species yet to be discovered  Tree of life - Biologists think life should be classified according to evolutionary relationships - Groupings correspond to time of divergences Major groupings show very early divergences Minor groupings show more recent divergences DNA comparisons - Required to determine evolutionary relationships - DNA of closely related organisms should be more similar than DNA of distantly related organisms Gene for making rRNA Domains - Domains: large groupings of modern species according to similarities in cell structure; represents biological relationships and ancient divergences; used since 1990 Bacteria: prokaryotes w peptidoglycan Archaea: prokaryotes w/o peptidoglycan Eukarya: organisms w eukaryotic cells - Domains of bacteria and archaea Oldest forms of life, 3.6 bil Prokaryotes = no nucleus or organelles Mostly unicellular and microscopic - Microorganisms: microbes - Studied by microbiologists Cyanobacteria (blue-green algae) - Photosynthesize: supplied by oxygen to atmosphere - Fix nitrogen - Found anywhere and able to survive extreme conditions - Endospores: allow some to resist adverse conditions - Domain eukarya: organisms w genetic material within nucleus in cells - Oldest eukaryotic fossils are 2 billion years old - Endosymbiotic theory: Mitochondria and chloroplasts descended from bacteria inside primitive Eukaryotes Symbiotic relationship was mutually beneficial Cells became tied together Kingdoms - Kingdom protista  Simplest known eukaryotes Mostly single-celled, but some w multicellular forms Resemble animals, fungi, and plants Most members are still unknown Algae: photosynthesize to make food Others consume organic molecules - Can digest cellulose that humans cannot - Kingdom animalia 1.2 billion years ago: multicellular organisms appeared Edicarian fauna: ancient, many-celled creatures of 600 million years ago - Vertebrates: animals w backbone Represent 4% of animal species Compete w humans Share some human traits and behaviors - Invertebrates: Animals w/o a backbone 96% of animal species Rival human capabilities - Kingdom Fungi Immobile, multicellular eukaryotes Many reproduce by releasing spores Heterotrophic - Secrete digestive chemicals - Absorbs small, digested molecules - Hyphae grow over and within food Decomposers in nutrient cycling Studied by mycologists Commercial uses of fungi: - Yeast: single-celled - Mold: quickly reproducing and fast growing Fungal relationships: - Ant parasites Change ant’s behavior Consume ant from within - Mycorrhizae Mutualistic symbiosis w plant roots Found in 90% of all plants - Kingdom plantae Present on land 400 million years - First plants  Small and low to ground Lacked vascular tissues - Evolution of vascular tissue: transports water and nutrients Allowed growth to tree size Allowed colonization in drier areas - Evolution of seeds Protected and provided food source for young plants on dry land - Viruses: Organic entities that interact w living organisms but are not alive Nonliving = no homeostasis or reproduction Consist of a strand of DNA or RNA surrounded by protein capsid Uses transcription machinery of host cells to reproduce Infected cells cannot perform other functions Examples of viral pathogens: Polio, smallpox, etc Reconstructing evolutionary history - Evolutionary classification: reflects evolutionary relationships Descendants of common ancestors Developing evolutionary classification - Species have two-part names: Genus species - Phylogeny: The evolutionary relationship - Cladistic analysis: technique to examine variation in traits of closely related species Difficulties in reconstructing evolutionary relationships - Situations complicating reconstruction Loss of evolved traits in descendent species Similar traits in unrelated species by convergent evolution give false impression Testing evolutionary classifications - Scientists use info from fossils and living organisms Fossil examinations - Genealogy: Record of descent from ancestors Living organisms - Patterns of DNA - DNA sequences do not support sparrow phylogeny