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EVOLUTION
EXAM 2 MATERIAL
| Question | Answer |
|---|---|
| When did the universe come into existence | 14 Billion Years ago |
| When our solar system was formed | 4.6 Billion Years ago |
| Organisms synthesize and use this type of amino acids | L optical isomers |
| One way simple organic molecules can be produced | abiotic chemical reactions |
| Name of experiment thatused electric discharges to atmospheric components to yield simple organic molecules through an abiotic process | Miller-Urey |
| Why does all life have Left-handed amino acids | Because all life has a common ancestor (Grand Homology) |
| First mistake in replication | Variation |
| Differential success among variants | Evolution |
| Prebiotic Synthesis | Self-replicating molecules |
| what are Heterotrophs | Comsumed free-floating amino acids and/or small bacteria to obtain energy |
| Archean Eon | 3.8 to 2.5 Billion Years ago |
| Archean and Proterozoic Eons are also known as this time | Precambrian |
| What photosynthesis evolved in cyanobacteria and other bacteria introduced | Oxygen into the atmosphere |
| What are the Three Domains organisms are classified in | Eucarya, Archaea, Bacteria |
| What are Banded Iron Formations (BIF's) | Formed only in the Precambrian from about 3.0-1.8 BYA indicating the beginning of photosynthesis |
| Origin of eukaryotes from prokaryotes came from this | Endosymbiosis |
| Two examples of endossymbiosis | Mitochondria and Chloroplasts |
| Mitochondria was deriverd from | Purple bacteria |
| Chloroplasts were derived from | cyanobacteria |
| Advantage of Multicellularity | Provided a division of labor between different cell types with different functions |
| Charnia is this | Oldest known multicellular organism (600 MYA) |
| Ediacaran Fauna of late Proterozoic and Early Cambrian | Among the oldest multicellular animal fossils found (~65MYA) |
| What is Kimberella | Earliestg known example showing 1) Bilateral Symmetry, 2) Coelom or body cavity, and 3)Shell-like covering |
| Precambrian Events | Eukaryotes diversify,metazoans appear and radiate, Cambrian Explosion |
| What is the Cambrian Explosion | Period of time (~540MYA)where there was a rapid occurance of diversification and abundance of Hard=bodied aniamls |
| Advantages of sex | 1) Vastly increases genetic diversity and 2) Diversity allows for rapid adaptation to changing conditions |
| What is the Hadeon Era | 4.5 to 3.8 BYA Earth formed but was smoking rock, extreme heat, volacism, asteroid bombardment |
| Formation of the Moon occured by this | Collision with mars-sized object and Earth |
| What is the Burgess Shale | Most fossils from ~ Half Billion Years ago found here |
| What is Pikaia | Found in Burgess Shale. Earliest known Chordate showing 1)Bilateral symmetry 2)Sensory organs 3)Concentrated anteriorly 4)Notochord running the length of the body 5)V-shaped muscle pattern |
| What are Trilobites | Dominated Cambrian (540-240MYA, common fossils, Primary index fossil of the Paleozoic |
| Ordovician Era | 488-444MYA, all major phyla present, reef communities develop, and provided major adaptive radiation in response to new habitat |
| What are Agnathans | Jawless fish that radiated in the Ordovician Era |
| What is the Ordovician Mass Extinction | Global cooling caused a sea-level drop and loss ofshallow marine habitat. 85% species extinct |
| Devonian Era | 416-354 MYA |
| Formation of the Moon occured by this | Collision with mars-sized object and Earth |
| What is the Burgess Shale | Most fossils from ~ Half Billion Years ago found here |
| What is Pikaia | Found in Burgess Shale. Earliest known Chordate showing 1)Bilateral symmetry 2)Sensory organs 3)Concentrated anteriorly 4)Notochord running the length of the body 5)V-shaped muscle pattern |
| What are Trilobites | Dominated Cambrian (540-240MYA, common fossils, Primary index fossil of the Paleozoic |
| Ordovician Era | 488-444MYA, all major phyla present, reef communities develop, and provided major adaptive radiation in response to new habitat |
| What are Agnathans | Jawless fish that radiated in the Ordovician Era |
| What is the Ordovician Mass Extinction | Global cooling caused a sea-level drop and loss ofshallow marine habitat. 85% species extinct |
| Devonian Era | 416-354 MYA where sub classes of biny fish and gave rise to the first terrestrial vertebrates and tetrapods. Adaptive radiation of terrestrial vascular plants |
| What is Tiktaalik | Earliest known organism that showed the first transition from water to land |
| What is the Late Devonian Mass Extinction | ~354MYA where 70% species lost due to possibly global cooling &/or anoxia |
| What is the Carboniferous Era | Balance of atmosphere due to deforestation (leading to more dissovled Oxygen in air) causing the Oxygen:Carbon Dioxide ratio to increase 30%. Time of giant insects(Arthropleura. Also gave rise to the amniotic egg |
| What is the Permian/Triassic Mass Extiction | ~248MYA where 95% species extinct due to possibly bollide impact, volcanism, and climate change caused from the fusion of Pangea. Complex life almost ended |
| What is the Mesozoic Era | Divided into 3 periods: 1) Triassic (251-200MYA),2)Jurassic(200-145MYA),3)Cretaceous(145-65.5MYA). Also known as the age of the reptiles |
| What is an Anapsid | No temporal openings |
| What is a Synapsid | Has an additional temporal opening for muscle attachments |
| What is an Euryapsid | Has a temporal an upper opening in the skull |
| What is a Diapsid | Has pair of temporal openings in the skull |
| What is a Saurischia | Type of dinosaur that has a "lizard-hipped" pelvis shape that the pubis points cranially (T-Rex) |
| What is an Ornithischia | Type of dinosaur that has a "bird-hipped" pelvis shape that the pubis is parallel with the ischium pointing caudally (Parasaurolophus) |
| What is Archaeopteryx | Oldest known bird |
| Earlist placental mammal | During the Early Cretaceous Period. Example is an Eomaia |
| What is the Cenozoic Era | "Age of giants/mammals. from ~65.5MYA to present |
| What is Biogeography | Study of the geographic distributions of organisms, attempts tgo solve |
| Darwin's Origin of Species contained three concepts of Biogeography | 1) Environment is insufficient to explain organismal variation between regions; 2) Barriers to free-migration are related to variation between regions; 3) Inhabitants of the same regionare more closely related than with inhabitants of different regions. |
| What is an Endemic species range | Species that share the same endemic (restricted) range, tend to be more closely related(Darwin's Finches on Galapogos Islands) |
| What are Analogous Organisms | 2 different species that inhabit similar niche and occurs through convergent evolution. Example: Placental vs Marsupials |
| What is Disperal | Expansion of the range of a species |
| What is Vicariance | Separation of populations by geographic barriers. Leads to evolution of placental and marsupial mammals (Vicariance hypothesis are often tied to paleogeography) |
| What is Allopatric Speciation | Speciation resulting from vicariance |
| What is Sympatric Speciation | Speciation occurring between two populations within the same region (Few, if any, examples of this) |
| What is a Cosmopolitan species reange | Species that share a range that extends across all or most of the world in appropriate habitats (killer whale). |
| What is Phylogeography | Description and analysis of the processes that govern the geographic distribution of lineages of genes, especially within closely related species |
| What is the Fundamental Ecological Niche of the Population | The set of all environmental conditions in which a species can maintain a stable poulation size |
| What is the Realized Ecological Niche of Population | The range of environmental conditions that a species actually occupies. May be further restricted if the species is excluded by competitors or predators |
| What is Phylogenetic Niche Conservatism | Species (Related) that often have similar ecological requirements, presumably derived from a common ancestor |
| What is Taphonomy | the study of the processes (as burial, decay, and preservation) that affect animal and plant remains as they become fossilized; also: the processes themselves |
| What is Taphonomic Bias | 1)Small poulations-fossilize well, large bones, low energy environment, high sedimentation. 2)Large populations-fossilize well, boney, low energy environment, high sedimentation rate. 3)Huge populations-Rarely fossilizes, no hard parts |
| What is Foraminifera | Possibly the most common fossil, Astronomically abundant, Calcite (CaCo3) bodies |
| Three characteristics that determine Speciation or Extinction | 1)Degree of Ecological Specialization. 2)Geographic Range. 3)Population Dynamics |
| What Determines Speciation or Extinction in the Degree of Ecological Specialization | Patchy distribution based on resources=Speciation. Tenuous resources=Extinction |
| What Determines Speciation or Extinction in the Geographic Range | Areally restricted species are more likely to undergoallopatric speciation, than broadly distributed species=Speciation Areally restricted species by be extinguished by local environmental changes=Extinction |
| What Determines Speciation or Extinction in the Population Dynamics | low population size promotes geographic separation=Speciation the population mean is affected more by changesin a sub-population if nis small=Speciation Small populations are more susceptible to extinction |
| Speciation vs Extinction | Taxa with high rates of speciation tend to have high rates of extinction(i.e. higher species turnover) |
| What is the Background Rate of Extinction | ~one species per million speciesper year, or between 10 and 100 species per year |
| What is a key adaptation | Adaptation that enables an organism to occupy a substantially new ecological niche, often by using a novel resource or habitat |
| What is an adaptive zone | Set of similar ecological niches |
| Natural Selection is what | Random Variation = Differencces in Fitness Purposeless, Non-Random Selection |
| Ehat is an adaptation | Characteristic that enhances the survival or reproduction of organisms that bear it,relative to alternative character states particularly plesiomorphic conditions. Can be:1)Anatomical, 2)Behavioral, 3)Physiological |
| What rule drives emergent complexity | The Mandelbrot Equation: g(z) = z2+ c |
| What is a Meme | Cultural entity analogous to a gene. Ex: song,idea, religion. Meme variants are selected by Meme replicators and thus evolve |
| What is Positive Natural Selection | Selection that drives an increase of favorable traits |
| What are mutations | Raw material for evolution. Changes in DNA sequences due to DNA replication mistakes of DNA damage. DNA replication mistakes made at low frequency |
| What is are the Types of Mutation | 1)Point Mutation-Alteration in a single nucleotide. 2)Indel-Insertion or Deletion 3)Duplication |
| Types of Point Mutations | 1)Non-Synomonous(Missense)-Mutations that change encoded amino acid. 2)Nonsense-Mutations that yield a stop codon 3)Synomonous(Silent)-Mutations that don't change encoded amino acid |
| What is Recombination | Not always a source of mutation, but represents another molecular level process that shapes genomic variation. Can alter thecombination of allelesfound on a chromosome |
| What is Homologous Recombination | Shuffling of genetic material mediated by crossing over btwn chromosomes. Recombination btwn Non-Homologous regions can cause mutations,dupl, deletions,translocations |
| What will eventually happen to mutations | Loss or Fixation (could take a long time) |
| What forces govern the fate of mutations (Population-Level Processes) | Natural Selection and Genetic Drift. These 2 forces are directly responsible for change in genome over time |
| What is Genetic Drift | Change in allele frequencies(phenotypes) across generations due to chance events. Eventually results in loss or fixation of each allele through non-adaptive means |
| Why changes occur more rapidly in small populations | Chance has more drastic effect when sample sizes are low. Resulting in small populations have greater potential to undergo rapid/drastic changesin allele frequency...and to lose/fix alleles all together...due to chance alone |
| What are Alleles | Differant variants of the same gene or "locus" |
| What is a substitution | Replacement of one nucleotide or allele with another within a population |
| What is a polymorphism | Existence within a population of two or more genotypes,rarest exceeds low frequency (1%) |
| If a trait is under (partial) genetic control, then... | Alleles(DNA sequences)that increase fitness will increase in frequency (positive selection) Alleles that reduce fitness will decrease in frequency(purifying or negative selection) |
| Neutralist-Selectionist Debate | Debate btwn biologists and geneticists over degree of genetic variation and how it was maintained. Formed 2 primary schools of thought: 1)Classical School, 2)Balance School |
| What was the Classical School side | Genetic Var. is low w/in species,Most members of same species should have homozygous alleles at all genes,Heterzygous loci due to activity of recurrent mutation,Harmful mutations gone (-)selection,Fixed alleles mutation r neutral,adapt mutation occur rare |
| What was the Balance School side | Genetic Variation high w/in species, Balancing selection(selection that maintains polymorphism)maintains variation, Members of same species are commonly Heterozygous across many loci,Natural selection acts to maintain variation |
| Types of Balancing Selection | 1)Spatially Varying Selection, 2)Heterozygote(Overdominance)Advantage 3)Multiple Niche Polymorphisms 4)Frequency Dependenr Selection |
| What is Spatial Varying Selection | Smooth cline in allele frequencies may be established if there is gene flow among populations along a gradient |
| What is Heterozygote(Overdominance)Advantage | Higher fitness in heterozygotes will act to maintain multiple alleles. Someteimes one of the alleles haas a higher fitness cost, when homozygous, than the other |
| What is Multiple Niche Polymorphism | Different phenotypes are differentially adapted to microhabitats/niches. Requires environmental heterogeneity and trade-offs. |
| What is Frequency Dependent Selection | Fitness of a given phenotype depends on its frequency w/in population |
| What did Kimura Notice about proteins from different species | Noticed that proteins from different species evolve at similar rates most likely due to drift |
| What is the Neutral Theory of Molecular Evolution | Great majority of evolutionary mutant substitutions at the molecular level are caused by random fixation,thru sampling drift, of selectively neutral mutants under continued mutation pressure |
| As population increases, genetic diversity w/in a population should... | Increase |
| what is Ka/Ks ratio | Ratio btwn non-synonymous(Ka):synonymous(Ks) substitutions across related organisms for a given gene, to detect (+)selection in protein coding genes. <1 = Purifying(-)selection =1 = Neutral evolution >1 = Positive Selection favors amino acid replaceme |
| Which genes are commonly evolving via Positive Selection (Ka/Ks > 1) | Genes involved with Immunity and Reproduction |
| What are the predominant roles in molecular evolution | 1)Genetic Drift, and 2)Purifying(-)Selection |
| How does Positive Selection play a factor in molecular evoluion | 1)Driven the fixation of amino acid substitutionsin genes involoved in immunity and reproduction, 2)Favored retention & driven evolution of some duplicated genes that acquired novel functions, 3)Likely favored retention of favorable transposons |
| Molecular evidence of Evolution | Cytochrome C |
| What is EvoDevo | Seeks to understand the mechanisms by which development has evolved,both in terms developmental processes, & evolutionary processes |
| What is Direct Development | Embryos develop directly into adult-like forms |
| What is Indirect Development | Embryos first pass through a larval stage |
| What are Deuterostomes | 1)Anus opening made first from blastopore 2)General Anterior/Posterior Patterning 3)General Dorsal/Ventral Patterning 4)Bilateral Symmetry |
| What are the HOX (Homeotic) Genes | Transcription Factors, each has conserved homeobox sequence that control the patterning of specific body structures. Control identity of segments along Ant-Post body axis |
| Experimental evidence also shows that the basic genes that pattern the body have also been conserved over this time. Thus, alterations of these “genetic toolkit genes” can lead to... | Significant alterations in body form and function. |
| What is the phylogenetic concept of homology | Homologus features are those that arise from a common ancestor in which the feature first evolved,Homologous SX r synapomorphies, similar in position relative to other body SX & some SX features, presence of inter forms among species or ontogeny |
| What is Biological Homology Concept | Suggests that a feature may be homologous among species at one level of organization (phenotypic), but not at another level (genetic or developmental)Constructed from set of conserved tools,Sig #downstream circ that master regs can control,tinkering=spec |
| What are "eyeless"/PAX6 | Master control gene that controls the development of the eye. "eyeless" in flys Pax6 in mammals |
| What are Evolutionarily Conserved Developmental Pathways | Proteins that relay molecular signals between cells, transcription factors, receptor, which respond to these signals by upregulating or downregulating target genes |
| What are Cis-regulatory elements | Enhancers, promoters…that tell a gene when and where to turn on. A change in when and where that gene’s function is turned on during development Diff arget genes of that same T.F. @ diff times during development and in different tissues during developme |
| Example of how turning off gene expression works in regulation | The evolution of webbed feet in ducks via interactions btwn BMP4 & Gremlin |
| What is BMP4 | A gene encoding a protein called bone morphogenetic protein 4 (BMP4) is expressed in the spaces between the developing bones of the toes and instructs the cells in those spaces to undergo apoptosis, destroying the webbing between the toes. |
| What is Gremlin | A BMP inhibitor protein |
| How ducks kept their webbed feet | When Gremlin is expressed, it prevents BMP4 from signaling apoptosis in the webbing, thus the webbed feet remains |
| What is Trans-regulatory | Differences between species and development due to the difference in the transcription factors themselves. Changes in the protein coding sequence: possible, but due to pleiotropyof protein function, will alter ALL of that protein’s functions. |
| What are Co-option and the evolution of novel characters | Genes and pathways have multiple dev roles, depend on when and where they r Xpressed in development,Redeployment of pathways and genes to serve new functions,Co-option (recruitment)-Xpress of a gene past its norm Xpression pattern & new area in developmen |
| Example of Co-option & Evolution of Novel characters | Distal-less is used to organize the development of outgrowths from the body (limbs, wings, antennae, etc). But it is also used in late stages of wing development to form the eyespots on the wings of some butterflies. |
| What is Heterochrony | One mechanism to change gene expression by changing the timing of developmental events. |
| Example of Herterochrony | Timing of somitedevelopment (leading to vertebrae number) is slow in mammals, leading to less vertebrae than snakes, where timing is much faster. |
| What is Allometry | Allometric growth is a change in the rate of growth of a dimension or feature relative to other features. |
| Example of Allometry | Some evol changes that produce Bat wings- are like paws with really long fingers and skin stretched btwn them.The rate of growth of finger bones incr relative to growth of bat's body—or rate of growth of rest of the body decreased relative to the fingers. |
| What are Environmental Influences on Developmental Patterns | Developing organisms respond to signals such as day length, temperature, and precipitation in such a way that the adults they become are adapted to the predicted conditions. |
| What are the Developmental Constraints and Morphological Evolution | 10Physical Constraints; 2)Selective Constraints; 3)Genetic Constraints; 4)Developmental Constraints |
| What are the Physical Constraints | Due to biology (DNA, bones, etc). Ex. Oxygen diffusion rates in trachea of insect bodies sets a limit on insect size. |
| What Re the Selective Constraints | Some features are disadvantageous |
| What are the Genetic Constraintgs | May be some limit in the regulation of the developmental pathways that control development (optimal transcription factor level or convergence of multiple developmental pathways that control too many cellular processes) |
| What are the Developmental Constraints | A lineage’s development may limit the sorts of phenotypes that it can evolve. Naturally occurring variations can be constrained by intrinsic differences in species specific developmental programs |
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md586
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