Term
______, the change in gene frequencies within a species over time, operating over the last several billion years, has produced Earth’s diversity. It happens through a variety of mechanisms. |
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Definition
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Term
______ is the primary mechanism of evolution. Other mechanisms include ______, ______, and ______. Basically, evolutionary mechanisms include processes that lead to the rejection of the ______. |
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Definition
Natural selection mutation migration genetic drift Hardy-Weinberg Law |
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Term
______ is the null hypothesis (Ho) for evolution and states that gene frequencies do not change and genotype frequencies do not change after one round of mating. Note that there is a long list of assumptions associated with a population that obeys this law over time. |
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Definition
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Term
______is the process that generates variability upon which natural selection operates. |
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Definition
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Term
Phenotypic traits often exhibit bell-shaped ______ (often graphed using a "histogram"). It is these trait distributions that change due to ______, ______ (or ______), or ______. |
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Definition
frequency distributions directional stabilizing balancing disruptive selection |
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Term
______ is the close, usually coevolutionary relationship between species. This may be a positive (mutualism) or negative (e.g., parasitic) interaction. |
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Definition
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Term
______ are ______ that fix their own energy for growth. ______ assimilate energy through the consumption of other organisms (living or dead). |
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Definition
Autotrophs primary producers Heterotrophs |
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Term
______ suggests that the growth rate of a population is limited by the scarcest resource. Related is ______ which suggests that populations are limited by resources that either are below or exceed a tolerance level. |
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Definition
Liebig's law of the minimum Shelford's law of tolerance |
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Term
______ (NPP) is equal to gross PP minus loss to respiration and drives higher trophic level productivity. |
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Definition
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Term
Average ______ is low, medium, and high for terrestrial, aquatic macrophyte, and aquatic algal systems, respectively. |
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Definition
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Term
Population growth rates are generally normally distributed (bell-shaped histogram) over a variety of ______ |
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Definition
environmental conditions. |
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Term
Populations grow ______, unless acted upon by an outside force (much like Newton's first law of motion). Populations at low densities tend to ______ when environmental factors are favorable, modified by processes that affect growth rates (e.g., ______, or ______). For a single population the growth rate might experience ______, reducing the growth rate due to ______. The simplest model of this is called ______ (dN/dt = rN[1-N/K]) where populations generally increase or decrease toward a non-trivial equilibrium called the ______. |
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Definition
geometrically increase interspecific competition predation intraspecific competition density dependent regulation logistic growth carrying capacity (K) |
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Term
At very low densities populations can decline due to the ______, which is brought about through ______, ______, ______, ______ (e.g., mates can’t find each other), ______ (Ne), and other negative effects. |
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Definition
Allee Effect demographic stochasticity environmental stochasticity, genetic inbreeding social dysfunction near-zero effective population sizes |
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Term
A ______ is a species’ set of resource requirements and the role a species plays in a community. It includes the spatial, temporal, biotic, and abiotic characteristics of the habitat. The ______ includes environmental conditions under which a species could exist. The ______ is the portion of the fundamental niche under which the species actually exists in nature |
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Definition
niche fundamental niche realized niche |
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Term
______ affect population dynamics. These are often modeled using matrices such as the ______. |
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Definition
Age-, stage-, and size-class distributions Leslie matrix |
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Term
______ is the trend that the range of organisms is correlated with latitude |
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Definition
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Term
Closely related animals often are larger at higher latitudes (______) and exhibit relatively smaller limb sizes (______). |
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Definition
Bergmann's Rule Allen’s Rule |
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Term
Ecologists use increasing levels of aggregation to describe individual species: ______, ______, ______, and ______. ______ are groups of interacting species. |
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Definition
individuals groups populations metapopulations communities |
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Term
Populations often occupy a fraction of habitable patches with individuals moving among patches (______). Some patches may exhibit positive growth while others exhibit negative growth rates (referred to as ______). |
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Definition
metapopulations source-sink dynamics |
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Term
Life history reproductive patterns are classified as either ______ or ______. Iteroparous species have overlapping generations. |
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Definition
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Term
Organisms exhibit one or more of these ______, which are scale-dependent: ______ (VMR>1), ______ (VMR<1), or ______ (Ho). The patterns can be differentiated with the variance/mean ratio. |
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Definition
spatial dispersion patterns clumped uniform random |
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Term
______ are classified in terms of their effects between two interacting species (or individuals). These include ______ (-, -), ______ (+, -), ______ (+, -), ______ (+, - [but not necessarily]), ______ (+, +), ______ (+, 0), and ______ (-, 0). |
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Definition
Ecological interactions among species competition predation parasitism/ pathogenic herbivory mutualism commensalism amensalism |
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Term
As a plant community develops there is an inverse relationship between the mean size of individuals and density (called the ______ or the ______). |
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Definition
-3/2 law "law of self-thinning" |
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Term
The role of a ______ in a community is so important that its removal causes significant changes in the structure and/or function of the system well beyond its relative abundance or mass within the community. |
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Definition
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Term
Two species with identical resource requirements will lead to ______. Coexistence is a very active research topic, however, with much work being done on spatial and temporal partitioning of resources. |
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Definition
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Term
A ______ occurs when species, functional groups, or members of trophic levels cause large-scale changes in other trophic levels. |
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Definition
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Term
The ______ is close to 10% because of the second law of thermodynamics, producing the ______. |
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Definition
transfer of energy between trophic levels Eltonian pyramid of energy |
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Term
Species that interact with other species through eating or being eaten form a structure called a ______. Food webs are classified by ______, ______, and/or ______ |
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Definition
food web connectedness energy flow function |
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Term
Pioneer communities are generally dominated by ______. Pioneer plants are shade-intolerant. Later development species are typically ______. Such plants are generally shade-tolerant. |
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Definition
r-selected species k-selected |
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Term
______ ("succession") occurs over time and involves compositional and functional changes in resident species. This process is classified in different models: ______, ______, ______, ______, ______, and ______ models. |
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Definition
Community development relay floristics individualistic dynamics initial floristics composition facilitation inhibition tolerance |
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Term
The ______ states that the highest level of species diversity occurs at intermediate levels of disturbance. |
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Definition
intermediate disturbance hypothesis |
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Term
______ independently described models used as a starting point for understanding the dynamics of ______ and ______ systems. |
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Definition
Lotka and Volterra preditor-prey competition |
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Term
______ tends to ______ with increasing latitude and increasing altitude. |
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Definition
species diversity decrease |
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Term
______ tends to ______ with increasing area (______). |
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Definition
species diversity increase species-area relationship |
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Term
Diversity in isolated patches is generally ______ compared to equal-sized areas in larger contiguous habitats. |
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Definition
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Term
The number of species on an island is a balance between species ______ and ______ rates (______). |
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Definition
colonization extinction theory of island biogeography |
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Term
Species assemblages vary across ______ due to the interactions among ______, ______, and ______. |
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Definition
biogeographical realms climate plate tectonics evolutionary history |
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Term
Terrestrial biomes are determined largely by ______, ______, ______ (the relationship between annual precipitation and temperature), and ______. |
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Definition
geology geography climate species composition |
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Term
In general, areas with ______ tend to exhibit ______ in response to disturbances. |
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Definition
higher diversity greater stability |
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Term
Energy ______ while nutrients tend to ______ |
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Definition
flows through ecosystems cycle |
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Term
______ of systems influences processes ranging from physiology to global-scale dynamics. |
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Definition
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Term
Strong evidence suggests human activities are causing ______. |
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Definition
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Term
______ are tested using ______ (natural and manipulative). Their results are analyzed using ______ and ______ models. "______" that continue to hold up to repeated tests and large amounts of data are eventually promoted to the status of a "______," such as the theory of evolution. Nothing in science is ______. All results are ______. |
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Definition
Scientific hypotheses experiments mathematical statistical Hypotheses theory proven provisional |
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