542140
Descripción
Fichas por jennabarnes12387, actualizado hace más de 1 año
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Creado por jennabarnes12387
hace casi 11 años
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| Pregunta | Respuesta |
| What is natural selection? | the ability of a population to developing and refining adaptive traits to meet environmental challenges through evolution. These traits can show up by chance in an organism and increase its success in survival and reproduction. |
| Why is natural selection slow and subtle? | the traits must be able to be passed to offspring. the population is subject to evolution while only the individual is effected by natural selection |
| what is directional selection? | when one phenotype is favored over another e.g. during different water levels in an environment a different beak depth in a species of finch survives better |
| What is disruptive selection? | when the extremes of a phenotype are favored. e.g. big and small plants do well but not medium plants |
| what is stabilizing selection? | the intermediate of the phenotype is favored. e.g human babies should be between 3-4 kg. any bigger or smaller, there will be issues |
| Why are there no perfect organisms? (3) | often adaptions are compromising, such as the lower part of the human spin being prone to weakness in exchange for upright standing. also the variations are limited to genetic history and can only change existing information. some adaptions don't even help an organism survive, they just happen |
| what is anagenesis? | when one species gradually turns into another species until the parent species no longer exists. |
| What is cladogenesis? | one one species gradually turns into another species but the parent species will still exist |
| What is the tempo or speed of speciation? | gradualism, first proposed by Hutton which is the gradual change through the sum of many small genetic changes |
| How can gradualism as a way to describe speciation be criticized? | many fossils stay unchanged and then suddenly disappear |
| A new paper about the tempo of speciation was published by Eldredge and Gould? What did they propose as an alternative? | punctuated equilibrium which is a time of unchanged genetic information followed by a period of speciation. this can be supported by looking at the tests of dead protists. It is seen that the shells remain unchanged for a long time followed by short period of speciation, this cycle repeating until change was obvious. |
| How many different species concepts do we study? What are they called? | 4. Biological, ecological, morphological, and phylogenetical. |
| what is the biological concept? | species are groups that can interbreed to produce fertile offspring |
| what is the ecological concept? | a species is a group that shares a niche in there environment |
| what is the morphological concept? | a species is a group that have the same structural features. usually used when classifying organisms that are already dead |
| what is the phylogenetic concept? | a species is a group that is located in one of the smallest groups at the top of a phylogenetic tree |
| what is reproductive isolation? | factors that stop the ability of different species from mating or producing offspring. |
| what is prezygotic inhibition? | when either the physical structure of the species inhibits mating or the egg and sperm cannot join if mating does occur |
| What is post-zygotic inhibition? | if a two species do mate, the fertilized zygote cannot be carried to term or cannot survive to a fully fertile adult or the offspring is sterile |
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