V. Evolutionary Ecology
What does it mean when evolutionary biologist refer to the "ecological theatre"?
"Ecological theater": the environment represents the backdrop and the evolutionary processes represent the play. Ecology influences evolution and vice versa.
Trait / Adaptation
-Trait is a distinguishing quality or characteristic. -Adaptation is the change or the process of change by which an organism or species becomes better suited to its environment
Artificial selection
Artificial selection is the breeding of specific individuals for desirable traits.
Why should evolution be included in the science of ecology?
Because the evolution of traits takes place in an ecological setting and these traits determine the range of possible interactions.
What influences differential reproductive success?
Fitness (survivability of a specific genotype), genetic variation and ecological factors (such as limited resources, environmental factors and competition) all influence differential reproductive success.
1.) Individuals within populations are variable 2.) Variation is heritable 3.) Survival and reproduction are non-random 4.) Organisms differ in survival and reproductive ability
What are the 4 main tenets of evolution?
Differentiate among the 3 types of selection:
(1.) Directional selection: natural selection favors one extreme of the population for that trait- e.g. climate gets colder, camouflage. (Example: Darwin's finches) (2.) Disruptive selection: natural selection favors both extremes selected, causes species to diverge. (e.g. Geospiza species) (3.) Stabilizing selection: natural selection favors the average for population selected- e.g. bird clutch size, human birth weight, human height.
Mimicry / Mimesis
*Mimicry and mimesis are types of directional selection.* -Imitates another organism (aposematic coloration); resemblance of one organism to another or an object in the environment, evolved to deceive predators -Imitates the environment (cryptic coloration); imitation or reproduction of the supposed works of another, as in order to represent his or her character
Ultimate / Proximate explanations
-A deeper reason why something happened; things that occur in populations over many generations. -A explanation that is closest to the event that is to be explained; things that occur during the life of an individual.
Abiotic agent of selection / Biotic agent of selection
-Abiotic agent of selection is a specific environmental element that causes the elimination of unsuited individuals, or one that places stress on individuals so that they are forced to cope in order to survive and reproduce. -Biotic agent of selection is another organism (predator/prey, competitor, mate) that immediately influences the survival and reproductive efforts of a species.
Cryptic coloration / Aposematic coloration
-Cryptic coloration is coloring that conceals or disguises. -Aopsematic coloration is markings that warn potential predators of nuisance or harm from attacking or eating it.
Differential mortality / Differential reproduction
-DIFFERENT MORTALITY is the tendency of some individuals in a population to produce more offspring than other individuals who die before reproductive age. -DIFFERENTIAL REPRODUCTION is the idea that those organisms best adapted to a given environment will be most likely to survive to reproductive age and have offspring of their own.
Fitness / Conditions
-Fitness is the ability to survive and reproduce in an environment. -Condition is how animals and plants interact and form ecological communities and ecosystems.
Gene / Allele / Locus
-Gene is the unit material of inheritance; small unit of a DNA molecule coded for specific protein to produce one of the many attributions of a species. -Allele is one or two alternative forms of a gene that arise by mutation and are found at the same place on a chromosome. -Locus is the position on a chromosome.
Phenotype / Genotype
-Phenotype is the physical expression of a characteristic of an organism, determined by both genetic constitution and environment. -Genotype is the genetic constitution of an organism.
What is the difference between sympatric, allopatric and parapatric speciation?
-Sympatric speciation is where populations are simultaneously overlapping; process through which new species evolve from a single ancestral species while inhabiting the same geographic region -Allopatric speciation is when species are divided into separate isolated group; occurs when a new species evolves in geographic isolation from its ancestor -Parapatric speciation occurs species are divided into separate isolated group
What are the 2 different kinds of traits? Provide examples of each.
-The two different kinds of traits are polymorphic and morphometric. -Polymorphic traits come in specific numbers of forms/morphs, vary discontinuously, and have phenotypes that occur in categories. -Morphometric traits are quantitative, vary continuously, and have phenotypes that occur among a continuum. -Eye color is an example of a polymorphic trait and height is an example of a morphometric trait.
What is a species? Be familiar with several different definitions.
-Typological definition: group of individuals that are morphologically distinct from other related groups. -Biological definition: group of individuals that are actually/potentially reproductively isolated from other groups. -Phylogenetic definition: group of individuals that share a unique feature that no other contains. (on a phylogenic tree, the lowest taxonomic level of interest are at the branch tips) -Ecological definition: a lineage that occupies a niche minimally different from that of any other lineage in its range-Basically, a species is a group of living organisms consisting of similar individuals capable of exchanging genes. -Cohesion species: combination of ecological and reproductive "cohesion" is important for maintaining a species' evolutionary unity and integrity (most inclusive groups of organisms having the potential for genetic and/or ecological cohesion). *Basically, a species is a group of living organisms consisting of similar individuals capable of exchanging genes.
Why is evolution thought to be "context dependent"?
All traits are thought to have evolved from previously existing traits. In the beginning, organs may have had the same or different function as it does today. Whether a given mutation is good or bad is determined by other mutations associated with it. An individual mutation can be beneficial if it occurs in combination with certain other mutations, but the same mutation can be detrimental to the organism if it occurs in other combinations.
Evolution
Evolution is a change in gene frequencies over time and measured by changes in percentages of individuals exhibiting specific forms of traits.
Provide an example of an organism in a natural population showing an adaptation for a particular environment, and discuss how that adaptation may show higher or lower fitness in a new environment. How and why is fitness both individual and environment dependent? Why is it that only population, and not individuals, evolve?
Longleaf pines are fire resistant; indigenous people adapted to thrive in the environment; Andean people have more hemoglobin and therefore carry more O2; Tibetan people breathe more to expand their blood vessels; etc. All of these adaptations are convergence, independent evolution of similar characteristic not derived from a common ancestor. Populations (not individuals) evolve because individuals in a population vary, some in the population are better able to survive and reproduce given a particular set of environmental conditions. These individuals generally survive and produce more offspring, thus passing their advantageous traits on to the next generation, causing a change in population overtime.
Use frequency distributional graphs to illustrate how natural selection might operate to produce population changes over time.
Look at graphs (Lecture 15 slides 4 and 5)
-Mutation is A source of new variation -Genetic drift is variation in relative frequency of different genotypes in a small population
Mutation / Genetic drift
Natural selection
Natural selection is the difference in survival or fecundity of individuals with certain phenotypes compared to individuals with alternative phenotypes, dependent upon variation in trait forms, fitness differences in trait forms, inheritance of trait forms and if so the trait frequency will change over time, change genetic composition and trait distribution of all offspring differ from parents.
How do the 2 subdisciplines of ecology differ and how do they relate to each other?
Subdisciplines of evolutionary ecology are ultimate and proximate. Proximate explanation is closest to the event that is to be explain/ things that occur during the life of an individual - human influences, abiotic changes, biotic interaction. Ultimate explanation are evolutionary influences, deeper reason of why something happen, and things that occur in populations over many generations.
What are the ultimate outcomes of the different types of selections?
Ultimate outcomes: leads to idea "what is a species?"
