Evolutionary Ecology Exam #1

Allele

a particular variant form of a gene Ex: the gene for flower color

Charles Darwin

born in 1808 in England, attended University of Edinburgh Medical School, interest in natural history, Christ's college, Cambridge, "Natural Philosophy" Voyage of the Beagle, discovery in Galapagos, theory of trasmutation

phenotypic plasticity in plants

deeper routes in response to water shortages, increased height in crowds, etc.

Proximity structure

defined by the size & composition of the group of neighbors that influence an organism's fitness

melanism in peppered moths

due to industrial pollution

hybrid vigor

introducing more genetic diversity to reduce negative effects of inbreeding

Outbreeding

mating between non-related individuals

Inbreeding

the mating of related individuals

Natural selection

Charles Darwin, the differential net reproduction of genetically distinct entities, whether mobile genetic elements, organisms, or entire species, occurs over a long period of time, acts on many organisms, may be diluted by environmental variation

Inbreeding depression

a decline in the characters of an individual, particularly in terms of characters of fitness, including viability & fecundity

Trait

a distinguishing quality or characteristic

Population

a group of individuals of the same species that inhabit an area, defined by scale

Population bottleneck

a sharp reduction in the population size due to an environmental even or human activities

Sexually dimorphic trait

a trait that differs between males & females Ex: birds; males have bright colors to attract females, females are duller to protect eggs without being seen

Quantitative trait

a trait the varies along a continuum Ex: speed of animal, some may be faster than others

Adaptation

a trait with a current functional role in the life history of an organism that is maintained & evolved by means of natural selection

environmentally induced changes

acclimatization, morphological, physiological, behavioral, phenological

Evolutionary ecology

an ecological science that focuses on the evolutionary histories of species & their interactions

Fitness

an organisms ability to survive, reproduce & pass on its genes to future generations, idea of natural selection, contributes to evolution

phenotypic plasticity in animals

aphids grow wings to move to new plants, digestive organs increase in response to low food availability

artificial vs. natural selection

artificial; breeding 2 closely related individuals, natural selection; acts on many organisms, occurs over a long period of time, may be diluted by environmental variation

Alfred Wallace

born in 1823 in Wales, interest in the natural world, On the Origin of Species, Darwinism, died in 1882, Voyage of the Mischief, theory of natural selection, similar ideas to Darwin, but not given much credit, Wallace's line, "The Malay Archipelago"

Mimicry

co-adaptation where one organism has adapted to resemble another Ex: bright colors in the rainforest represent poisonous creatures, some frogs use their brightness to deceive other, but it's not really poisonous

phenotypic patterns of natural selection

directional selection; favors organisms that are at a phenotypic extreme compared to the rest of the population, stabilizing selection; eliminates individuals with extreme traits & favors those with intermediate characteristics, disruptive selection; favors organisms that have character values at the extremes of the phenotypic distribution

3 types of traits

discrete, quantitative, sexually dimorphic

Age classes

dividing the population into discrete intervals representing similar probabilities of survival & similar fertilities, in which all individuals are treated as equal

adaptations are shaped by

environmental aspects that influence fitness, genetic correlation with phenotype, the organism's history

Genetic drift

fluctuation in the frequency of a gene variant as a result of accidents of genetic segregation Ex: Tasmanian devil

Inbred lines

groups of inbreeding organisms

homozygosity vs. heterozygosity

homo; 2 copies of the same allele, hetero; different alleles

Theory of transmutation

idea that one species/organism evolves into another

Wallace's Line

imaginary boundary line that runs between Australia & the Asian islands & mainland, marks the point where there is a difference in species on either side of the line

negative effects of inbreeding

inbreeding depression, reduced heterozygosity, reduced genetic variation, reduced fertility, increased mortality, reduced immunity to diseases, increased genetic disorders

benefits of adaptations

increased fitness of an organism, help animals survive their ecological niches

types of adaptation

life history (age at maturity, frequency of reproduction, # of offspring, size of offspring) , structural (what we see the most, camouflage/defense), behavioral, physiological

inbreeding coefficient results

low inbreed coefficient; high population (deer), high inbreed coefficient; low population, little genetic diversity

2 causes of genetic variation

mutation (permanent change) , sexual reproduction (creation of new genotype)

5 factors of population

natality, mortality, sex ratio, age distribution, dispersal

imperfections of adaptations

non-adaptive traits tied to adaptive traits (ex: peacocks, large tail attracts females, but also attracts predators), constraints of organisms (species can't reach their highest fitness potential) , response to selection varies (bird vs bees; birds grow longer beaks to reach nectar in flowers, bees becomes smaller to get into the flower to collect nectar)

why co-adaptation may be negative

organisms more susceptible to co-extinction, become too dependent on one another

Mutation

permanent change in the chemical structure of a gene Ex: a red fox being black & continuing to produce black individuals

3 things Darwin observed that must occur in order for natural selection to occur

reproductive excess, struggle for existence, variation in nature

semelparous vs. iteroparous

sem; the organism reaches maturity, reproduces & then dies, it will only reproduce once in its lifetime (ex: salmon) , itero; a pattern of repeated reproduction throughout the organism's lifetime (ex: elk, loons, iguanas)

how common is inbreeding in nature?

species w limited dispersal are often inbred, ex: fruit flies, pollen, coral, geographical separations or populations can lead to inbreeding, most inbreeding is due to humans

example of convergent evolution

sugar gliders vs. squirrels

Phenotypic plasticity

the ability of an organism to change its phenotype in response to changes in the environment Ex: plants; deeper routes in response to water shortage, larger leaves in response to increased shade, growing taller in response to crowded conditions

Ecology

the branch of biology dealing with the relations & interactions between organisms & their environment, including other organisms

Evolution

the change in genetic composition of a population over successive generations, which may be caused by natural selection, inbreeding, hybridization, or mutation

Life history

the cycle of birth, reproduction & death of an organism

Genetic structure

the distribution of genotypes in time & space, reflects the genetic differences that develop among different components of one or more populations of organisms

Homoplasy (convergent evolution)

the independent evolution of similar features in species of different lineages, not coming from a common ancestor, develop traits to prevent predation that ancestors before did not have Ex: sugar gliders vs. squirrels; are not related, developed ability to fly independently

Inbreeding coefficient

the probability of 2 mating individuals having an allele (gene variant) in common from a common ancestor -F=0; low inbreeding coefficient (deer), high populations -F=1; high inbreeding coefficient (pine), small population, little genetic diversity

Speciation

the production of a new, genetically distinct biological species

Heratability

the proportion of observed variation in a particular trait that can be attributed to inherited genetic factors Ex: when children only resemble their mother, not their father

Gene flow

the transfer of genes from one population to another, helps to not lose traits in a population, if gene flow is reduced it could result in inbreeding

Discrete traits

traits that do not have a range of phenotypes Ex: labs are either yellow, chocolate, or black

Environmental variation

variation in phenotype influenced by differing physical or biological environments

Genotypic variation

variation in the genetic makeup of an organism (genetic code), cannot see it

Phenotypic variation

variation in the physical appearance of an organism, can see it, can be an expression of genotypic variation

Homology

when a structure is present in an ancestral species & is retained in descendant species possibly with considerable evolutionary modification

Self fertilization

when an organism mates with itself, a form of inbreeding, occurs mostly in plants, but in other organisms as well (snails)