APES 5 & 6 Flashcards

7980316802	population	all individuals that belong to the same species and live in a given area at a particular time	0
7980316803	community	3rd level of complexity. All populations of organisms in a given area	1
7980316804	population ecology	study of factors that cause populations to increase or decrease	2
7980316805	population size	total number of individuals within a defined area at a given time	3
7980316806	population density	# of individuals per unit area @ a given time	4
7980316807	population distribution	how many individuals are distributed w/ respect to one another	5
7980316808	sex ratio	ratio of males to females	6
7980316809	age structure	how many individuals fit into particular age categories	7
7980316810	density dependent factors	limiting factor that depends on population size	8
7980316811	limiting resource	resource that a population cannot live without and that occurs in quantities lower than the population would require to increase in size	9
7980316812	carrying capacity	the number of individuals that can be sustained in an area	10
7980316813	density independent factors	Limiting factor that affects all populations in similiar ways, regardless of population size.	11
7980316814	growth rate	# of offspring an idividual can produce in a given time period, minus the deaths	12
7980316815	intrinsic growth rate	the maximum potential for growth of a population under ideal conditions with unlimited resources	13
7980316816	exponential growth model	model which estimates a population's future size	14
7980316817	j-shaped	starts slowly but then accelerates as the population increases because the base size of the population is increasing.	15
7980316818	logistic growth model	a description of idealized population growth that is slowed by limiting factors as the population size increases	16
7980316819	s-shaped	a plot of the number of individuals against time, also known as a logistic growth: involves rapid exponential population growth followed by a steady decrease in population growth with time until the population size levels off.	17
7980316820	overshoot	The extent to which a population exceeds the carrying capacity of its environment	18
7980316821	die-off	A rapid decline in a population due to death.	19
7980316822	k-selected species	Species that produce a few, often fairly large offspring but invest a great deal of time and energy to ensure that most of those offspring reach reproductive age.	20
7980316823	r-selected species	Species that reproduce early in their life span and produce large numbers of usually small and short-lived offspring in a short period.	21
7980316824	survivorship curves	They show the likelihood of survival at different ages throughout the lifetime of the organism.	22
7980316825	corridors	A strip of natural habitat that connects two adjacent nature preserves to allow migration of organisms from one place to another	23
7980316826	metapopulation	A collection of populations that have regular or intermittent gene flow between geographically separate units	24
7980316827	community ecology	the study of how interactions between species affect community structure and organization	25
7980316828	competition	the struggle between organisms to survive in a habitat with limited resources	26
7980316829	competitive exclusion principle	ecological rule that states that no two species can occupy the same exact niche in the same habitat at the same time	27
7980316830	resource partitioning	in a biological community, various populations sharing environmental resources through specialization, thereby reducing direct competition	28
7980316831	predatation	an interaction in which one organism kills and eats another	29
7980316832	pathogens	Microbes that cause disease	30
7980316833	mutualism	the relation between two different species of organisms that are interdependent	31
7980316834	commensalism	the relation between two different kinds of organisms when one receives benefits from the other without damaging it	32
7980316835	symbiotic	mutually beneficial; supporting one another's life	33
7980316836	keystone species	a species whose impact on its community or ecosystem are much larger and more influential than would be expected from mere abundance	34
7980316837	predator mediated competition	Competition in which a predator is instrumental in reducing the abundance of a superior competitor, allowing inferior competitors to persist.	35
7980316838	ecosystem engineers	species that dramatically alter their environment	36
7980316839	ecological succession	series of changes in the species in a community, often following a disturbance	37
7980316840	primary succession	the series of changes that occur in an area where no soil or organisms exist	38
7980316841	secondary succession	succession on a site where an existing community has been disrupted	39
7980316842	pioneer species	first species to populate an area during primary succession	40
7980316843	theory of island biogeography	The number of species found on an island is determined by a balance between two factors: the immigration rate (of species new to the island) from other inhabited areas and the extinction rate (of species established on the island). The model predicts that at some point the rates of immigration and extinction will reach an equilibrium point that determines the island's average number of different species (species diversity).	41
7980316844	Ecosystem Diversity	The variety of ecosystems	42
7980316845	Species diversity	The variety of species	43
7980316846	Genetic diversity	variety of genes	44
7980316847	Species richness	The number of different species in a community	45
7980316848	Species evenness	Abundance of individuals within each species contained in a community	46
7980316849	Evolution	A change in the genetic composition of a species over time	47
7980316850	Microevolution	Change in gene frequencies between populations of a species over time	48
7980316851	Macroevolution	Evolutionary change above the species level, including the appearance of major evolutionary developments, such as flight	49
7980316852	Genes	physical locations on chromosomes within each cell of an organism	50
7980316853	Genotype	complete set of genes in an individual	51
7980316854	Mutation	occasional mistake in the copying process produces these random changes	52
7980316855	Recombination	A combining of genes or characters different from what they were in the parents	53
7980316856	Phenotype	An organism's appearance or other detectable characteristics	54
7980316857	Evolution by artificial selection	selective breeding of domesticated plants and animals to produce offspring with desired genetic traits	55
7980316858	Evolution by natural selection	the principle that, among the range of inherited trait variations, those that lead to increased reproduction and survival will most likely be passed on to succeeding generations	56
7980316859	Fitness	ability to survive and reproduce	57
7980316860	adaptations	traits that improve an individual's ability to survive and reproduce	58
7980316861	genetic drift	The gradual changes in gene frequencies in a population due to random events	59
7980316862	bottleneck effect	a reduction in the genetic diversity of a population caused by a reduction in its size	60
7980316863	founder effect	random change in the gene pool that occurs in a small, isolated colony of a population	61
7980316864	geographic isolation	Separation of populations as a result of geographic change or migration to geographically isolated places	62
7980316865	reproductive isolation	Separation of species or populations so that they cannot interbreed and produce fertile offspring	63
7980316866	allopatric speciation	The formation of a new species as a result of an ancestral population's becoming isolated by a geographic barrier	64
7980316867	sympatric speciation	The formation of new species in populations that live in the same geographic area	65
7980316868	genetic engineering	Process of making changes in the DNA code of living organisms	66
7980316869	genetically modified organisms	An organism whose genetic material has been altered through some genetic engineering technology or technique	67
7980316870	range of tolerance	Range of chemical and physical conditions that must be maintained for populations of a particular species to stay alive and grow, develop, and function normally	68
7980316871	fundamental niche	The full potential range of the physical, chemical, and biological factors a species can use if there is no competition from other species	69
7980316872	realized niche	Part of a species fundamental niche that it actually uses, limited by competition	70
7980316873	distribution	the areas in the world where a species actually lives	71
7980316874	niche generalists	a species that can live under a wide range of abiotic or biotic conditions	72
7980316875	niche specialists	a species that is specialized to live in a specific habitat or to feed on a small group of species	73
7980316876	fossils	Preserved remains of once-living organisms	74
7980316877	mass extinction	Event in which many types of living things become extinct at the same time	75
7980316878	Why is it challenging to determine the number of species on Earth?	It is challenging because some species are active only at night or live in inaccessible locations.	76
7980316879	Why are estimates of species diversity valuable to environmental scientists?	They are valuable because they can tell environmentalists how much diversity is in a given area and what animals dominate it.	77
7980316880	What is the difference between species richness and species evenness? Why are they both important measures?	The number of species in a given area, such as a pond, the canopy of a tree, or a plot of grassland, is known as species richness. However, species evenness tells us whether a particular ecosystem is numerically dominated by one species or whether all of its species have similar abundances. They are both important measures because they reflect biodiversity.	78
7980316881	What is evolution, and what are the three main ways in which it occurs?	Evolution is the change in the genetic composition of a population over time. It occurs by artificial selection, by natural selection, and by random processes.	79
7980316882	How are artificial and natural selection similar? How are they different?	With artificial selection, organisms are produced that humans find pleasing. However, with natural selection, the environment determines which individuals survive and reproduce. They are similar because traits are assigned to organisms in both cases.	80
7980316883	How does evolution lead to biodiversity?	Evolution produces more changes within a species, therefore increasing diversity.	81
7980316884	How does geographic isolation lead to reproductive isolation?	If individuals cannot move between the populations, then over time, the two geographically isolated populations will continue to become more and more genetically distinct. Eventually, the two populations will be separated not only by geographic isolation, but also by reproductive isolation: they will become so different that even if the physical barrier were removed, they could no longer interbreed and produce viable offspring.	82
7980316885	What factors influence a species' chances of adapting successfully to a change in its environment?	The factors are rate of environmental change, genetic variation, population size, and generation time.	83
7980316886	Why is the pace of human-driven evolution faster than that of natural evolutionary processes?	Using genetic engineering techniques, scientists can now copy genes from a species with some desirable trait, such as rapid growth or disease resistance. However, natural evolution occurs very slowly.	84
7980316887	How do fundamental niches and realized niches differ?	The suite of ideal conditions is termed the fundamental niche of the species. However, the addition of biotic factors more narrowly defines the parts of the fundamental niche that a species actually uses. The range of abiotic and biotic conditions under which a species actually lives is called its realized niche.	85
7980316888	How does environmental change determine species distribution? When does it lead to extinction?	Species vary in their ability to move physically across the landscape as the environment changes, so species distribution is affected. It leads to extinction when the environmental change is so severe that the organism cannot survive there any longer.	86
7980316889	How are human activities affecting extinction rates, and why is their impact a particular concern?	Human causes include habitat destruction, overharvesting, introductions of invasive species, climate change, and emerging diseases. Because much of the current environmental change caused by human activities is both dramatic and sudden, environmental scientists contend that many species may not be able to move or adapt in time to avoid extinction.	87