Flashcards
Environmental Science Midterm 2 -- Evolution, biodiversity, pop. Ecology
Cards in this deck (48)
- 1Anoxic Atmospherein 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 - 2Early Earth : Evolutionary EventsNutrients 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 - 3Biological EvolutionGenetic change in populations of organisms across generations
May be random or directed by natural selection - 4Natural Selectionthe process by which traits that enhance survival and reproduction are passed on more frequently to future generations than those that don’t
- 5Why 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 - 6Genetic Variation : Adaptive Traita trait that promotes the reproductive success
- 7Genetic Variation: Mutationsaccidental changes in DNA that may be passed on to the next generation
non lethal mutations provide genetic variation on which natural selection acts - 8Genetic Variation: Sexual Reproductionthe production of new living organisms by combining genetic information from two individuals of different types (sexes)
also leads to variation - 9Directional Selectiondrives a feature in one direction/extreme phenotype is favored over other phenotypes
(thick shells favoured) - 10Stabilizing SelectionProduces intermediate traits, Instead of favoring individuals with extreme phenotypes, it favors the intermediate variants. It reduces phenotypic variation
- 11Disruptive SelectionTraits 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.
- 12Divergent Evolutionone 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 - 13Convergent Evolutionthe process by which unrelated organisms evolve similar body forms, coloration, organs, and adaptations. Natural selection can result in evolutionary convergence
- 14explain lactose tolerance in humansa 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 - 15Speciesa population or group pf populations whose members share characteristics and can freely breed with one another and produce fertile offspring
- 16Populationa group of individuals of a species that live in the same area
- 17Allopatric Speciationspecies formation due to physical separation of populations
can be separated by glaciers, mountains, rivers etc.
the main mode of species creation - 18Extinctionthe 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 - 19Endemic Speciesa species only exists in a certain, specialized area. these species:
-are very susceptible to extinction
-usually have small populations - 20Earth Mass extinctionsfive events in earth's history that killed off massive numbers of species at once
humans are causing the sixth mass extinction event - 21Biospherethe total living things on earth and the areas they inhabit
- 22Ecosystemcommunities and the nonliving material and forces they interact with
- 23communityinteracting species that live in the same area
- 24population ecologyinvestigates the quantitative dynamics of how individuals within a species interact
- 25community ecologyfocuses on interactions among species
- 26Ecosystem ecologystudies living and nonliving components of systems to reveal patterns
eg. nutrient and energy flows - 27Habitatthe environment in which an organism lives -- includes living and nonliving elements
- 28Habitat useeach organism thrives in certain habitats, but not in others
- 29habitat selectionthe 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 - 30sympatric speciationspecies form from populations that become reproductively isolated within the same area
eg. feed in diff areas, mate in different seasons - 31Nichean 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 - 32specialistsspecies with narrow niches and very specific requirements
extremely good at what they do, but vulnerable to change - 33Generalistsspecies with broad niches that can use a wide array of habitats and resources
able to live in many different places - 34Population sizethe number of individual organisms present at a given time
numbers can inc., dec., cycle, or remain the same - 35Population densitythe 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 - 36Population Distributionspatial arrangement of organisms within an area
Random: no pattern
Uniform: individuals evenly spaced due to territory
Clumped: arranged according to availability of resources - 37Birth and Death Ratesbirth/death rates = rates per 100 individuals
survivorship curves = likelihood of death varies with age - 38survivorship curves: Type 1more death rates at older ages
- 39survivorship curves: type 2equal number of death at all ages
- 40survivorship curves: type 3more deaths at young ages
- 41exponential population Growthsomething 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 - 42what factors restrain growth?physical, chemical and biological characteristics are limiting factors that restrain population growth
(water, space, food, predators, and disease) - 43Carrying Capacitythe 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 - 44Density-dependent Factorslimiting factors whose influence is affected by population density
increased risk of predation and competition for mates occurs with increased density - 45Density-Independent Factorslimiting factors whose influence isn't affected by population density
events such as foods, fires, and landslides - 46Biotic Potentialthe ability of an organism to produce offspring
- 47K-Selected Speciesanimals with long pregnancy periods and few offspring
have low biotic potential - 48R-Selected Speciesanimals which reproduce quickly
have high biotic potential
Little parental care
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- User has deleted their subject information Flashcards on Environmental Science Midterm 2 -- Evolution, biodiversity, pop. Ecology, created by Deleted user on 01/04/2018.
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- Deleted user · Apr 2018
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- Created by abby Radske · Mar 17, 2018
- Copied by abby Radske · Apr 1, 2018
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