66 Cards in this Set
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Fundamental Principle of Ecology #1
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organisms are distributed in space and time in a heterogeneous manner
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Fundamental Principle of Ecology #2
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organisms interact with their abiotic and biotic environments.
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Fundamental Principle of Ecology #3
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the distribution of organisms and their interactions depends on contingencies.
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Fundamental Principle of Ecology #4
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environmental conditions are heterogenious in space and time
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Fundamental Principle of Ecology #5
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resources are finite and heterogeneous in space and time.
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Fundamental Principle of Ecology #6
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Birth and Death are a consequence of interactions with the abiotic and the biotic environment.
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Fundamental Principle of Ecology #7
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Ecological properties are the result of evolution.
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Fundamental Principle of Ecology #8
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All phenomena that are studied in ecological theories are variable in their characteristics.
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Natural Selection
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the process of picking among the fit and less fit organisms. The "sorting hat" of life. Natural Selection acts on individuals, and leads to evolution only when it chooses among heritable variants.
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Homology
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similarity of traits between different species resulting in shared ancestry. Comes from variations on a structural theme present in a common ancestor.
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Analogy
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two structures that are similar at present, but NOT due to shared ancestry.
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Morphological Divergence
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animals with homologous structures due to a common ancestor. (not from a shared ancestor, but a COMMON ancestor)
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Morphological Convergence
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some body parts with similar form or functions that evolved independently can result when different lineages are subjected to similar environments and similar selection.
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Microevolution
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Microevolution is the occurrence of small-scale changes in allele frequencies in a population, over a few generations, also known as "change below the species level". Used to understand the dynamics of "genes" in populations.
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Allele-Gene Relationship
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the gene is the "governing body" which determines which allele will be expressed.
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Allele
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an alternate variation of a gene.
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population
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a troup of the same species in a specific location. They can interbreed and produce fertile offspring.
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Gene Pool
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the total aggregate of alleles in a population at any one time "pooled" from all individuals.
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Phenotype vs. Genotype
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phenotype- physical characteristics genotype- particular allel sequence expressed.
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phenotypic frequency
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recessive to dominant allelic ratio in proportion to the total number of individuals.
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genotypic frequency
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the number of specific genotypes per the total number of individuals.
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Hardy-Weinberg Equilibrium
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definition... describing a population whnich is not evolving and is at genetic equilibrium. The frequencies of alleles and genotypes in the gene pool remain constant. (the water line in the pool stays the same)
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Hardy-Weinberg Equilibrium
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conditions... 1. Yes, Large population size (no genetic drift) 2. No gene flow (no migration) 3. No mutations 4. No natural selection 5. Yes, Random mating
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Hardy-Weinberg Equations
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f(A)= p f(a)=q p+q=1 (p^2)+2pq+(q^2)
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mutation
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the source of a new variation/alleles. It is ultimately the source of ALL variations. These are heritable changes.
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Recombination
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(aka sex) shuffles combinations of alleles... it does not: generate new variation, change allele frequencies, or change genotype frequencies. Recombination does NOT lead to evolution.
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Genetic Drift
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Describes statistically how allele frequenceis fluctuate unpredictably from one generation to the next. it tends to reduce genetic variation through losses of alleles.
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Bottleneck Effect
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a sudden drastic reduction in size of a population. The new population will have less genetic diversity than the original. *(genetic mapping of diseases relies on the bottleneck effect of ancestors of humans)
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Geneflow
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genetic additions or subractions from a population, resulting from movement of fertile individuals or gametes.
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selection
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favors certain genotypes by acting on phenotypes of individuals. there are three types: directional, disruptive, stabilizing.
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Directional Selection
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favors individuals at one end of the phenotypic range.
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Disruptive Selection
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favors individuals at BOTH extremes of the phenotypic range.
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Stabilizing Selection
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favors intermediate variatns and ats against extreme phenotypes.
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Trade-offs
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given limited time and resources, how can an organism best use themselves to maximize fitness? ex: european magpies egg #/nest optimum
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Major Trade-offs
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1. Current vs future reproduction 2. Reproduce vs. Survive (as reproduction increases, adult survival decreases) 3. Grow vs. Reproduce.
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logic of adaptation by natural selection
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observations: populations can grow. populations are stable in the long-term resources are limited individuals vary relatives resemble each other (therefore some variation is variable)
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logic of adaptation by natural selection
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inferences: there is a struggle for existence survival/reproduction are NOT random favorable characteristics become more common over generations
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Logic of adaptations by natural selection
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conclusion: populations adapt to their environment b/c individuals vary, variation influences survival and reproduction, and variation is heritable.
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Examples of Adaptation
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artificial selection HIV drug resistance
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Adaptive radiation
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diversification of species descended from a RECENT common ancestor
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natural selection vs evolution vs adaptation
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"Evolution BY Natural selection CAN PRODUCE adaptations"
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5 Processes of Evolution
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improving: 1. Personal survival 2. Survival of young 3. Ability to secure nourishment/energy 4. Cooperative strategies 5. Intellect, cultural, and tool using.
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Anagenesis
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evolutionary change along a single branch of a phylogeny.
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Cladogenesis
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evolutionary divergence into two or more descendent lineages (one species may look like the ancestor)
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What makes a species a species?
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characteristics unique to that organism/ group of organisms and successful reproduction
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Biological Species Concept
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-defines species in terms of reproductive isolation -members of the same species: -have the potential to interbreed in nature -produce viable, fertile offspring -cannot produce successful offspring with members of other populations. (imperfect view of "species")
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Reproductive Isolation
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*not geographic* the existance of BIOLOGICAL factors that impede members of two species from producing viable, fertile hybrids. --can be a combination of many reproductive barriers
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Prezygotic Barriers
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impede mating between species by hindering the fertilization of the ova if members of different species attempt to mate.
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Postzygotic barriers
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-prevents hybrid zygote from developing -prevents hybrid adult from reproducing -weakens hybrid individual
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Prezygotic barriers to reproduction
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Habitat isolation Temporal Isolation Behavioral Isolation Mechanical Isolation Gametic Isolation
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Habitat Isolation
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ex: thamnophis garter snakes live in different habitats.
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Temporal Isolation
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ex: spilogale gracilis mates in summer; s. putoris mates in winter.
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Behavioral Isolation
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courtship rituals are often very formal, and creativity goes unrewarded.
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Mechanical Isolation
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Structural differences between individuals that physically prevent successful mating.
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Gametic Isolation
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sperm fails to reach or penetrate the egg.
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If prezygotic barriers are absent or surmounted, a ____ ____ is formed
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hybrid zygote
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postzygotic barriers to reproduction
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-reduced hybrid viability -reduced hybrid fertility -hybrid breakdown
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reduced hybrid viability
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occurs if the hybrid zygote fails to mature or is FRAIL. -potential causes: embryonic, post embryonic, weak adult.
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Reduced hybrid fertility
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mule or hinny example
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Hybrid breakdown
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generation after first hybrid generation is weak or sterile.
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Biological Species concept does not apply to...
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-Fossils -Asexual reproducing species -microbes -organisms where distant hybridization can be successful -Organisms about which little is known regarding reproduction -Widely separated populations -"Ring" species
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Morphological Species Concept
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characterizes a species in terms of its body size, shape, and other STRUCTURAL features.
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Ecological species concept
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views a species in terms of its ECOLOGICAL NICHE
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Phylogenic species concept
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defines a species as a set of organisms with a unique GENETIC HISTORY
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Allopatric speciation
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a population can form a new species when a barrier arises that geographically separates it. ex: sticklebacks
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sympatric speciation
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a small population becomes a new species without geographic separation. ex: Drosophila paulistorum
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BIOL 301: Resource Partitioning