12863370
Description
Flashcards by abby Radske, updated more than 1 year ago
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Created by abby Radske
over 6 years ago
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| Question | Answer |
| Anoxic Atmosphere | in the absence of oxygen life developed in unicellular form because multi-cellular life requires too much energy, which later oxygen provided oxygen was poison at first |
| Early Earth : Evolutionary Events | Nutrients in the hot water, such as hydrogen and methane, contain energy in the form of electrons As time went on, RNA developed and then further complexified and eventually was able to self-replicate and catalyze simple reactions DNA developed, became more stable ensuring the genetic info was lass susceptible to destruction, later surrounding itself with lipids : LUCA |
| Biological Evolution | Genetic change in populations of organisms across generations May be random or directed by natural selection |
| Natural Selection | the process by which traits that enhance survival and reproduction are passed on more frequently to future generations than those that don’t |
| Why is Evolution Vital? | It alters the genetic makeup of a population It is important for understanding antibiotic and pesticide resistance, agricultural issues etc. Organisms adapt to their environment and change over time |
| Genetic Variation : Adaptive Trait | a trait that promotes the reproductive success |
| Genetic Variation: Mutations | accidental changes in DNA that may be passed on to the next generation non lethal mutations provide genetic variation on which natural selection acts |
| Genetic Variation: Sexual Reproduction | the production of new living organisms by combining genetic information from two individuals of different types (sexes) also leads to variation |
| Directional Selection | drives a feature in one direction/extreme phenotype is favored over other phenotypes (thick shells favoured) |
| Stabilizing Selection | Produces intermediate traits, Instead of favoring individuals with extreme phenotypes, it favors the intermediate variants. It reduces phenotypic variation |
| Disruptive Selection | Traits diverge in two or more directions/ extreme values for a trait are favored over intermediate values. In this case, the variance of the trait increases and the population is divided into two distinct groups. |
| Divergent Evolution | one species evolves in many different directions usually a result of diffusion of the same species to different and isolated environments which blocks the gene flow among the distinct populations allowing differentiated fixation of characteristic |
| Convergent Evolution | the process by which unrelated organisms evolve similar body forms, coloration, organs, and adaptations. Natural selection can result in evolutionary convergence |
| explain lactose tolerance in humans | a long time ago, no humans could digest lactose migration from the Middle East, people began to keep animals for meat and cheese eating cheese caused a mutation where people could eat lactose |
| Species | a population or group pf populations whose members share characteristics and can freely breed with one another and produce fertile offspring |
| Population | a group of individuals of a species that live in the same area |
| Allopatric Speciation | species formation due to physical separation of populations can be separated by glaciers, mountains, rivers etc. the main mode of species creation |
| Extinction | the disappearance of a species from earth occurs when a species cannot adapt quickly enough to a changing environment irreversible: once a species is lost, it is lost forever |
| Endemic Species | a species only exists in a certain, specialized area. these species: -are very susceptible to extinction -usually have small populations |
| Earth Mass extinctions | five events in earth's history that killed off massive numbers of species at once humans are causing the sixth mass extinction event |
| Biosphere | the total living things on earth and the areas they inhabit |
| Ecosystem | communities and the nonliving material and forces they interact with |
| community | interacting species that live in the same area |
| population ecology | investigates the quantitative dynamics of how individuals within a species interact |
| community ecology | focuses on interactions among species |
| Ecosystem ecology | studies living and nonliving components of systems to reveal patterns eg. nutrient and energy flows |
| Habitat | the environment in which an organism lives -- includes living and nonliving elements |
| Habitat use | each organism thrives in certain habitats, but not in others |
| habitat selection | the process by which organisms actively select habitats in which to live availability and quality of habitats are crucial to an organisms well being human developments conflict with this process |
| sympatric speciation | species form from populations that become reproductively isolated within the same area eg. feed in diff areas, mate in different seasons |
| Niche | an organisms use of resources and its functional role in a community habitat use, food selection, role in energy and nutrient flow, interactions with other individuals |
| specialists | species with narrow niches and very specific requirements extremely good at what they do, but vulnerable to change |
| Generalists | species with broad niches that can use a wide array of habitats and resources able to live in many different places |
| Population size | the number of individual organisms present at a given time numbers can inc., dec., cycle, or remain the same |
| Population density | the number of individuals within a population per unit area high densities make it easier to find mates, but increase competition etc. low densities make it harder to find mates, but get plentiful resources and space |
| Population Distribution | spatial arrangement of organisms within an area Random: no pattern Uniform: individuals evenly spaced due to territory Clumped: arranged according to availability of resources |
| Birth and Death Rates | birth/death rates = rates per 100 individuals survivorship curves = likelihood of death varies with age |
| survivorship curves: Type 1 | more death rates at older ages |
| survivorship curves: type 2 | equal number of death at all ages |
| survivorship curves: type 3 | more deaths at young ages |
| exponential population Growth | something increases by a fixed percent graphed as a J shaped curve cannot be sustained indefinitely, it only occurs in nature with a small population and ideal locations |
| what factors restrain growth? | physical, chemical and biological characteristics are limiting factors that restrain population growth (water, space, food, predators, and disease) |
| Carrying Capacity | the maximum population size of a species that its environment can sustain like an exponential growth, but levels off due to the limiting factors slowing/stopping exponential growth |
| Density-dependent Factors | limiting factors whose influence is affected by population density increased risk of predation and competition for mates occurs with increased density |
| Density-Independent Factors | limiting factors whose influence isn't affected by population density events such as foods, fires, and landslides |
| Biotic Potential | the ability of an organism to produce offspring |
| K-Selected Species | animals with long pregnancy periods and few offspring have low biotic potential |
| R-Selected Species | animals which reproduce quickly have high biotic potential Little parental care |
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