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Biology Unit 3
Speciation, Taxonomy, & Systematics
| Question | Answer |
|---|---|
| species | replicate amongst one another but not with individuals outside species. produce viable, fertile offspring. common characteristics, common gene frequencies. group of organisms that maintains a distinctive set of attributes in nature |
| difficulty in identifying a species | a single species may exist in 2 distinct populations that are in the slow process of evolving into 2 or more different species. Most microscopic. |
| difficulty in identifying a species cont. | amount of separation time for 2 pop. short time=likely to be similar&considered same species. long time=likely to show unequal differences. may find situations where some differences are apparent but difficult to decide if two pop are diff species |
| macroevolution in geographical isolation | so significant that new species arrive= natural selection is working. evolutionary changes that create new species and groups of species. occurs by accumulation of micro evolutionary changes.(change in a single gene) small changes over along period oftime |
| phylogenetic species concept members of same species can look very diff, members of diff species can look vary similar | species identified by having an unique combination of traits. historically used physical traits, now use dna sequences. advantage: can be applied to all organisms dis: # traits to consider, traits that vary in a continous way, |
| biological species concept | a species is a group of ind. whose members have the potential to interbreed with one another in nature, produce viable fertile offspring but cannot successfully interbreed with members of other species. reproductive isolation prevents breeding with others |
| biological species concept | may be difficult to determine if 2 populations are reproductively isolated (allopatric). cases when 2 species can interbreed but do not (sympatric). cannt be applied to asexual species |
| ecological species concept | each species occupies an ecological niche. within their own niche, members of a given species compete with each other for survival. if 2 organisms are very similar, their needs will overlap resulting in competition. (likely to be same species) |
| niche | : unique set of habitat resources that a species requires as well as its influence on the environment. |
| prezyogtic isolating mechanisms | effectively maintain the species-specific barriers leading up to conception or gene mixing. habitat vs geographic isolation. prevent formation of zygote. prebreeding |
| prezygotic temporal isolation | tempus=time. reproduce at different times of the day or year. different life cycles. physically they could but do not mate at the same time-> keeps them apart. males/white tail deer. 2/3 weeks. |
| prezygotic behavioural isolation | behaviour is important in mate choice. changes in song of birds and frogs. courtship behaviour of WT deer and mule deer. two meadow larks-> diff sounds to allow males/females to mate with right species. md->2-4 day wt-> 10 mins.diff tails. |
| prezyogtic mechanical isolation | a does not go into b. incompatible genitalia prevents mating. |
| prezygotic gametic isolation | species with external fertilization. gametes fail to unite successfully. important in species that release gametes into the water or air. ie fish egg covering stops incorrect sperm |
| postzygotic isolating mechanisms | occasionally prezyogtic rims break down. there is a secondary line of isolating mechanisms. less common in nature bc they are more costly in terms of energy&resources used. |
| postzygotic types | hybrid sterility-> interspecies hybrid &viable but sterile. inviability: fertilized egg cannot progress past an early embryo. causes spontaneous abortion. doesnt come to term. hybrid breakdown: viable&fertile offspring but later gen have abnormalities. |
| mechanisms in speciation | underlying cause of speciation is the accumulation of genetic changes that ultimately promote enough differences so that we judge a population to constitute a unique species |
| patterns of speciation. anagenesis vs cladogenesis. | A: gradualist mode/one species leads to emergence of another over a long period of time. ancestral line is extinct. gradualism. C: adaptive radiation, divergent evolution. |
| allopatric speciation | most prevalent method for cladogenesis occurs when some members of a species become geographically separated. charle's darwin used to explain finches. emergence of 2 or more species. can also occur when small pop moves to a new location. |
| adaptive radiation | single species evolves into an array of descendants that differ greatly, in habitat, form or behaviour |
| hypridization | zones of contact=more likelihood of hybrids. critical component in which we test the species barrier. hybrid zone: where 2 populations can interbreed. |
| reproductive isolation initiated in allopatry& concluded in sympatry. | 1: initiation. isolate small group from parent. 2: persist for a period of time, new elements bring back together, they will overlap and amte, or bring back&they will ignore each other. 3:viable hybrids but are they sterile? |
| Gradualism | each new species evolves continuously over long spans of time. large phenotypic differences that produce new species are due to the accumulation of many small genetic changes. |
| punctuated equilibrium | tempo more sporatic. species in equilibriumm for long periods and then short rapid burts of changes |
| gradualism vs punctuated equilibrium | brought to an end and then emergence of new species. start with long period of equilirium end with catrostrphic event, rapid evolutionary dates. evidence of both in fossil record. |
| taxonomy | layers at which we classify things. field of biology concerned with the theory, practise & rules of classifying living and extinct organisms and viruses. different naming systems that go from high level, very specific |
| systematics | study of biological diversity and the evolutionary relationships among organism, both extinct and modern. |
| Domain Archae | extreme ophiles (loving) organsims. less diverse than bacteria. discovered 1970. halophiles, methanogens, hyperthermophiles (halo:salt, hyper: hot temp) |
| Bacteria | diverse collection of many species, so widespread only generalizations about their ecology. key to success is metabolic diversity. myraid of shapes and sizes |
| protistia | simplest eukaryotes, most unicellular, some colonial or simple multicellular. some photozynthesize, some eat bacteria or other protists. aquatic habitats, "leftovers" from other three kingdoms |
| fungi | yeasts, molds, mushrooms. diverse. present worldwide in aquatic and terrestrial environments. many symbiotic with plants cell walls of chitin. most multicellular. mass of hyphae to make mycelium |
| plantae | multicellular, almost all capable of photosynthesis. mosses, ferns, conifers, flowering plants, cell wall of cellulose. |
| animalia | multicellular and eat others for food. more than 1 million species.ingest food&digest in internal cavity. bodies have cells organized in tissues. complex&rapid movement. nervous system. lack rigid cell wall. most heterotrophs(energy flow through them) |
Created by:
bdinney22
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