Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Sexual selection wikipedia , lookup
Organisms at high altitude wikipedia , lookup
Hybrid (biology) wikipedia , lookup
Evidence of common descent wikipedia , lookup
Theistic evolution wikipedia , lookup
Punctuated equilibrium wikipedia , lookup
Natural selection wikipedia , lookup
Genetic drift wikipedia , lookup
Sympatric speciation wikipedia , lookup
Hologenome theory of evolution wikipedia , lookup
Exam 5 Review: Evolution and Speciation Supplemental Instruction Iowa State University Leader: Course: Instructor: Date: Andre BIOL 211 Dr. Debinski, Dr. Heath November 6 Explain the differences between the theories explaining evolution over time. Greeks: Great Chain of Being – organized based on complexity Typological Thinking – all animals are specific unchanging types Lamarck: Inheritance of Acquired Characteristics Darwin: Theory of Evolution by Natural Selection – Pattern – evolution Process – descent with modification Evolution acts on populations Natural selection acts on individuals Explain the following evidences for evolution. Fossils: - Radioactive Decay Data: shows absolute ages of extinct animals – disproves typological thinking - Transitional Features: traits that are the intermediate between the ancestral species and the modern species - Law of Succession: fossil species are similar to the living species in the same area Vestigial Traits: non-functional traits in an organism, but similar or functional in another related organism Homology: Genetic Homology: similarity in DNA Structural Homology: homology occurring at the adult stages (similar structure) Developmental Homology: homology occurs during the developmental stages (embryonic development) Internal Consistency: data and research from independent sources to support a theory What are Darwin’s Four Postulates? How does modern science interpret them? 1. Individuals vary in their traits 2. Variations are heritable, then passed on to offspring 3. More offspring are produced than can survive 4. Certain heritable traits are better for survival and reproduction 1. Heritable Variation (1 + 2) 2. Leads to different reproductive success (3 + 4) 1060 Hixson-Lied Student Success Center 515-294-6624 [email protected] http://www.si.iastate.edu Compare the terms. Adaptation vs Acclimatization – adaptation is the heritable trait that increases fitness in a specific environment; acclimatization the genotype is staying the same, the phenotype is changing to the environment Polygeny vs Pleiotropy – polygenic traits are affected by multiple genes; pleiotropic traits are when a single allele is affecting multiple traits Pleiotropic traits are a genetic constraint on evolution Explain how the Theory of Evolution by Natural Selection is testable. 1. Drug resistant tuberculosis 2. Beak size and body size changes in Galapagos finches Mutations occur because the organism needs to adapt and solve a problem. Mutations occur at random T or False Evolution is progressive, continually producing better and more complex organisms. T or False There is no such thing as a “higher” or “lower” organism because each organism tends to be well adapted to their environment. True or F Define the following terms: The Modern Synthesis: era where scientists research proves evolution (Darwin’s theory) Gene Pool: genotypes and their frequencies in a population What is the Hardy-Weinberg Principle? p+q=1 p2 + 2pq + q2 = 1 p = dominant allele frequency q = recessive allele frequency p2 = homozygous dominant genotype 2pq = heterozygous genotype q2 = homozygous recessive genotype What is inbreeding depression and what does Heterozygote Advantage have to do with it? Inbreeding Depression – decline in fitness in a population because of increases in the homozygous individuals Heterozygote Advantage – advantage towards heterozygote individual’s fitness 1060 Hixson-Lied Student Success Center 515-294-6624 [email protected] http://www.si.iastate.edu What are the four mechanisms that change allele frequencies in populations? How is this related to the Hardy-Weinberg Principle? Natural Selection Genetic Drift Gene Flow Mutation Hardy-Weinberg CANNOT have any of the previous occurring because evolution would be happening in the population. Hardy-Weinberg also requires random mating Explain the four patterns of natural selection. Directional Selection: favoring one side/direction of characteristics Stabilizing Selection: favors the average, does not favor the extremes Disruptive Selection: favors the extremes Balancing Selection: all variations of the trait are equally favored What is genetic drift? Random change in the allele frequencies. Easily acts on small populations - Founder effect – a small new group starts a new population in a new area, resulting in changes to the allele frequencies - Bottleneck effect – large amount of original population is killed off, resulting in changes to the allele frequencies What is gene flow? Movement of alleles between populations What is mutation? Random change in a gene (most are deleterious, some are beneficial) Speciation… Explain how these changes result in speciation. 1. Genetic Isolation – gene flow is interrupted between populations 2. Genetic Divergence – characteristics change enough to prevent interbreeding between the said populations 1060 Hixson-Lied Student Success Center 515-294-6624 [email protected] http://www.si.iastate.edu There are 3 main approaches to identify a species. Explain each and provide examples. Biological Species Concept (BSC): Two species are different because they can’t interbreed or produce viable/fertile offspring Prezygotic isolation – before fertilization; based on habitat, behavior, mechanical differences Postzygotic isolation - after fertilization; offspring don’t survive or can’t reproduce Low hybrid zygote viability – doesn’t make it past the egg/developmental stage Low hybrid adult viability – lives, but it has a shortened life/weaker Hybrid infertility – lives, but completely infertile Morphospecies Concept (MSC): Different in size and shape and other physical features Disadvantages: Polymorphic Species – can be split into 2+ species Cryptic species – different in non-morphological/physical traits Phylogenetic Species Concept (PSC): Species are defined as the smallest monophyletic groups based on their evolutionary history Disadvantage: subspecies How is allopatric speciation different from sympatric speciation? Allopatric: different areas - Dispersal: group of organisms leaves a pop, moves to a new area and colonizes to form a new population - Vicariance: physical barrier splitting a population Sympatric: same area - External events: Disruptive selection based on ecological niches - Internal events: Chromosome mutation – polyploid speciation o Autopolyploid – offspring of a parent that self-fertilizes o Allopolyploid – parents that are different species When isolated populations come into contact, interbreeding can occur. Other outcomes include: - Reinforcement: selection occurring for traits that isolate populations - Hybrid Zones: the geographic area where 2 populations can interbreed and commonly have hybrid offspring 1060 Hixson-Lied Student Success Center 515-294-6624 [email protected] http://www.si.iastate.edu