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Bio 111 exam 2
| Question | Answer |
|---|---|
| biological species concept | a set of actually or potentially interbreeding populations |
| what species does the biological species concept apply to? | species that are sexual, extant, sympatric (occurs in the same place) |
| lineage species concept | a group of organisms that share a common ancestor, form a separate evolutionary branch, and continue evolving independently from other groups |
| what do species concepts emphasize? | different aspects of the speciation process |
| what is speciation? | the process of making a species |
| allopatric def and example | live in different places (geographic isolation). Ex) the founder effect with finches in the galapagos |
| parapatric def and example | living side-by-side. species are adjoined and then split. Ex) trees in the Amazon: white trees live in white sand habitats, while darker trees live in a clay, muddy habitat (they divided, but still in contact) |
| Example of sympatric | Lord Howe island has 2 species of palm trees that diverged there, and they need to flower at certain times (reproductively isolated) |
| Genome duplication | an organism has more than 2 complete sets of chromosomes (polyploidy). Gametes can split and don't reproduce |
| Allopolyploids | multiple sets of chromosomes from 2+ different species |
| Autopolyploids def and example | multiple sets of chromosomes all from the same species. Ex) bushes in south america appeared and then moved to north america. Hard to tell apart, closely related but isolated reproductively |
| Prezygotic barriers def and examples | Mechanisms that prevent two species from mating/prevent fertilization Ex) spatial, temporal, gametic, mechanical, behavioral, habitat |
| Postzygotic barriers def and examples | barriers for when after the zygote is formed (something goes wrong with development/survival/reproduction) Ex) hybrid zygote abnormality (horse + mule mating = donkey is sterile) |
| molecular evolution | evolution of DNA and protein sequences |
| Phylogeny | parent to offspring transmission of genes. Used to infer evolutionary relationships among species |
| Neutral Theory | gene and protein sequence evolution is dominated by the effects of genetic drift on neutral mutations |
| Polymorphisms | occurrence of 2+ different forms of a trait or gene in a population |
| Neutral mutations | synonymous base changes, base changes in introns and pseudogenes, non-synonymous base changes that don't affect protein function |
| Why is genetic drift more impactful in smaller populations? | because there can be a random loss of variation |
| What happens to deleterious mutations when they enter a population? | they are quickly eliminated |
| Where/how do beneficial mutations spread? | they spread to fixations which contribute little to polymorphism |
| what are most genetic polymorphisms for? | alleles of equal/very similar fitness |
| Molecular evolution rate =.... | neutral mutation rate |
| Mutation rate | fraction of gene copies carrying a new mutation in the next generation/time period |
| rate of neutral molecular evolution is independent of... | population size |
| molecular clock | used to estimate how long ago two species diverged from a common ancestor by looking at genetic differences in DNA/protein sequences. depends solely on mutation rate (occur in a clocklike manner) |
| what happens if most variation is neutral (molecular clock)? | differences among DNA sequences can be used to determine when past events occurred |
| what is selection more likely to act on (synonymous or non-synonymous) and why | non-synonymous, which cause amino acid change, and then a synonymous change |
| if synonymous = non-synonymous... | genetic drift occurs |
| if synonymous > non-synonymous.... | purifying selection occurs |
| if synonymous < non-synonymous... | positive selection occurs |
| orthologs def | copies of the same gene in different species descended from their common ancestor |
| paralogs | copies of the same gene in the same genome due to a gene duplication event |
| xenologs | horizontal transfer of genetic material between two distantly-related species |
| analogs | different genes in separate species that have converged to have the same function via separate evolutionary paths |
| positive selection | a genetic mutation increases an organism's fitness, causing that allele to increase in frequency in a population over time |
| purifying selection | removal of any harmful mutations from a population |
| synonymous mutation | changes a DNA codon but DOESN'T change the amino acid |
| non-synonymous mutation | changes the codon so that the amino acid changes (or becomes a stop codon) |
| what is the challenge of phylogeny? | some lineages split hundreds of millions/billions of years ago, but we only have phylogeny of recent species |
| what is taxonomy? | description, naming, and classification of organisms |
| Phylogenetic Analysis and example | shows evolutionary relationships in lineages. Ex) RNA genome mutated a lot, which caused lots of variation in different strains |
| Clade def | common ancestor and all descendant species |
| Outgroup def | used to infer ancestral state in ingroup |
| Monophyletic | common ancestor and ALL descendant species |
| Polyphyletic | doesn't include common ancestor |
| Paraphyletic def and example | common ancestor and SOME of the descendant species (ex we don't call birds "dinosaurs", though they descended from them |
| parsimony (phylogenetic methods) | minimize number of changes along branches. Shared derived characters are important |
| Cladogenesis | evolutionary splitting among lineages. Based on speciation for lineages at and above the species level |
| Anagenesis | evolutionary change within a lineage (population or species) |
| Systematics | evolutionary history of adaptation and diversification of a group |
| Maximum likelihood (phylogenetic methods) | allows for variation in the probability of different types of changes (ex synonymous vs. non-synonymous) |
| Bayesian analysis (phylogenetic methods) | computationally efficient method to explore parameter space and find best tree and parameter values to fit observed data |
| What can isotope dating do? and example | Isotopes have half-lives that can be used to date events (ex. isotopic analysis on a femur from the earliest known domesticated dog in North America; closest relative is a Cujo) |
| what 3 processes changed the composition of the atmosphere? | 1) volcanic activity 2) chemical reactions 3) photosynthesis: O2 as a product led to an oxygenation event |
| what's the main difference between the structures of bacteria and archaea? | bacteria- call walls of peptidoglycan (forms tough, rigid sheets); distinct protein-making machinery archaea- cell walls of polysaccharides (starches); protein-making machinery like Eukarya |
| How are ribosomes evolutionary ancient? | they're found in all of life (in common ancestor). they also play a critical role in translation |
| consequences of interfering with the gut community | -antibiotics: completely wipes out gut microbiome, hard to back to OG state -gut bacteria are environmentally acquired; we're born sterile -unusual microbiome and disease |
| evidence for endosymbiosis | -mitochondria and chloroplasts are double cell membranes -both contain DNA, organized as a circular chromosome |
| what happened in 1985 that gives evidence for endosymbiosis (mitochondria)? | small rRNA unit was sequenced of mitochondria. This sequence was nested within a form of bacteria |
| what happened in 1975 that gives evidence for endosymbiosis (chloroplast)? | chloroplasts from marine alga were much more similar to a prokaryotic sequence than to alga's nuclear sequence for rRNA |
| What's the problem with endosymbiosis? | a bacteria must consume a bacteria for endosymbiosis to work |
| what was found in 2010 that showed that eukaryotes evolved from archaea? | sediments from a hydrothermal vent in Loki's Castle were collected, showed a high diversity of Archaea. Multiple related archaeal phyla discovered |
| what are steranes and how are they used? | they're viral markers for eukaryotes. they can be used to get a date of how old eukaryotes are |
| what are rhodoplasts? | red algae and descendants (photosynthetic) |
| what are apicoplasts? | non-photosynthetic plastids |
| what is primary endosymbiosis? | heterotrophic protist (eukaryote) engulfs cyanobacterium. Retained, not digested |
| result of primary endosymbiosis? | -proplastid endosymbiont genome greatly reduced -plastid enclosed with inner and outer membranes of cyanobacterium endosymbiont |
| what is secondary endosymbiosis? | primary red or green alga engulfed by a second eukaryote |
| what do larger cells require more of? | more energy/unit time, so they require more O2/unit time |
| Basal metabolic rate and what is it usually measured by? | minimum energy that a cell needs to stay alive (usually measured as O2 consumption rate) |
| Fick's Law (equation) | flux = -(membrane permeability)(surface area)(concentration gradient) |
| Rate of diffusion equation | (area of diffusion surface)(difference in concentration)/(thickness/permeability of membrane) |
| What does the combination of diffusion time and diffusion rate do to a cell? | a) limits cell size b) influences body plan architecture of multicellular organisms |
| What are porifera and example? | sponges that have two layers. Have a "jelly" in b/w, and they pump water through their body to get thick, but they have NO circulatory system. Ex) flatworms increase their surface area, which is shape modification |
| What do spiders have that maximize their surface area (for O2 flow)? | they have a circulatory system that wraps around , so more surface area for blood + O2 to go all throughout body |
| what types of fish require more surface area to absorb O2? | larger fish and more active fish |
| Consequence of being large-bodied and benefit | More food consumed (cost) benefit: metabolism per unit mass decreases |
| Advantage of large body size (4 things) | -move faster than smaller organisms -ability to move in different directions -larger resource base -large organisms have specialized cells |
| what's the difference between somatic cells and germline cells? | somatic cells are mortal, while germline cells live forever |
| why does germline sequestration decrease mutation rate? (2 things) | -mitotic arrest (cells get stuck during mitosis and cannot complete cell division) -metabolic inactivity reduces oxidative activity |
| Synapomorphy def | shared, derived trait used to define a group of organisms |
| what is the closest multicellular relative to Anamalia? | Fungi |
| What arose due to the Cambrian Explosion? | lots of phyla in Animalia |
| How many phyla are in Animalia and what are they primarily? | 36 phyla, 95% of all Animalia are not vertebrates |
| what are ctenophora (common features)? | -comb jellies (phyla); they're all predators -have colloblasts: sticky structures attached to tentacles -living cells on the outside, get thickness by acellular reproduction -radial symmetry |
| what are placozoa | they're very very small organisms. They remain attached to rocks (all marine). They have 4 cell types, 11,000 predicted protein-coding genes |
| Gastrovascular cavity | one opening into digestive system, waste goes out |
| what are Cnidaria and what do they have (special feature)? | phylum that includes jellyfish, coral, etc. They have nematocysts (stinging cells to catch prey). They're active feeders |
| what is a coelom? | fluid-filled body cavity that's lined by the mesoderm. It's an opening in the interior of the body (to gain girth) |
| What is bilaterians-cephalization meaning? | animals that have bilateral symmetry and all their organs are towards the front of their body |
Created by:
madalynes