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)