Exam 2
Runaway sexual selection
elaborate traits that females are attracted to that willbe passed on to their sons and give them an advantage in their mating, and daughters will have the good genes that induces the preference. Exaggreated traits have a higher fitness b/c some females prefer them and some don't care.
GTS 12 - Quatenary
evolution of humans, large mammals and birds become extinct
Migration (Gene flow)
exchanging of genes between populations that makes them more similar to one another over time
Principle of Parsimony
favors hypothesis with fewest assumptions
Adaptation
feature of an organism that improves aspects of their performance in their environment that is a product of natural selection. - have the appearance of being designed for their habitat or sometimes they're less obvious.
Homologous Features
features of organisms that relate to one another through common descent ex: wing of bat, arm of human and flipper of whale share homologous bones
Sexual Selection - Female Choice
females are generally the "choosy sex" 1. Direct benefits 2. Runaway sexual selection 3. Good genes 4. Sensory exploitation
Direct Benefits
females that have a genetic predisposition to choose mates that provide them with tangible resources that increase their fecundity Ex: Male scorpion flies present nuptial gift before mating
Speciation
formation of 2 or more species from one. usually begins with lack of gene flow between populations.
Altruistic Trait
genetic trait that decreases the fitness of the individual who possesses it and increases the fitness of others. - Belding's ground squirrels that make alarm calls when a predator approaches
Selfish Trait
genetic trait that increase the fitness of the individual who possesses it and decreases the fitness of others.
Binomial Naming
genus, species
GTS 6 - Carboniferous
increase in diversity of reptiles, Earth is covered in wild forests
GTS 4 - Silurian
increase in the diversity of fishes
Sexual Selection- Male Competition
intrasexual: competition between the same sex for a mate intersexual: preferences for one sex that is looked for in another (women like mating with men who had red hair, the men with red hair would have an advantage) 1. Combat 2. Sperm competition 3. Infanticide
Sexual Selection 2
sexual selection is stronger on the sex that invests less, and that sex has more obvious traits and characteristics to help them attract mates. Example: Male peacock feathers to attract peahens Trivers' Parental Investment Theory - female increases her reproductivity by being choosy, while males increase reproductivity success by mating with many females.
Kin Selection
should only evolve when it increases the frequency of an individual's genes in the next generation whether directly or indirectly. - inclusive fitness: measure of the representation of your genes in the next generation
Contradictions to Theories
1. 15,000 years of co-existance, not wiped out 2. hade a gene similar to moderns for speech, probably had some form of communication 3. gene sequence suggests that they didn't interbreed 4. hunted marine life, not just large animals 5. "don't need a grapefruit spoon to eat a grapefruit" in respect to tools
Mating Systems
1. promiscous 2. monogamous: each female and male only mates with one 3. polygynous: males mate with several females, while females usually only mate with one male 4. polyandrous: each female mates with multiple males and males usually only mate with one female
GTS 10 - Cretaceuos
MASS EXTINCTION of dinosaurs, flowering plants begin to dominate life on land
Vestigial Traits
"pseudogenes" found in DNA that don't code for proteins but are found in other species DNA and show relatedness. ex: Vitamin C genes and the genetic code that is universal for all life
Neanderthals: Theories for Extinction
1. very variable climate 2. moderns wiped out Neanderthals 3. moderns and Neanderthals interbred 4. moderns outcompeted with Neanderthals because they had a more varied diet 5. Neanderthals had a higher metabolism and needed more calories and energy 6. moderns had a language 7. moderns had a longer life span, pass on knowledge and reproduce more
Post-Zygotic Barriers to Hybridization
1. zygote death 2. hybrid performance
GTS 2 - Cambrian
Cambrian Explosion: dramatic increase in the diversity of life that lasted briefly. introduced first vertebrates.
Selection
a. natural i. directional: individuals with one extreme of inherited phenotype have advantage over other individuals in the population (dark and light moths) ii. stabilizing: individuals with an intermediate value of an inherited phenotype have advantage over the other (birth weight in humans) iii. disruptive: individuals with either extreme of phenotype have an advantage over the individuals with an intermediate phenotype (beak size) b. artificial c. sexual - cause animals to have certain adaptations
GTS 11 -Tertiary
age of mammals begins
GTS 7 - Permian
age of reptiles begins. MASS EXTINCTION.
Hamilton's Rule
altruism should only evolve to increase your inclusive fitness benefit to recipient of altruism/cost to donor > 1/coefficient of relatedness or rb > c
GTS 5 - Devonian
amphibians appear. MASS EXTINCTION
Mutation
change in the bases along the DNA strand - only source of completely new genes - makes populations and individuals different from each other because the occur randomly, may or may not be beneficial - types: 1. point mutation: one base pair replaces another, length of strand remains the same 2. frameshift mutation: addition (insertion) or a deletion of a base pair
Evolution
change in the frequency of a phenotype caused by changes in allele frequency in a population. Summary of Evolution: 1. Mutations cause changes to occur at random 2. These random changes cause inherited genetic changes in individuals of a population 3. Gene flow, genetic drift and natural selection acting on that genetic variation can cause allele frequences to change in a population over time
Sexual Selection
change in the frequency of a trait based on competition for a mate
GTS 9 - Jurassic
continents begin to separate. first birds, first flowering plants
Spiteful Trait
decreases the fitness of both the possessor and others. - rotting-wood weevil that prevents other females from digging holes for their eggs while using up its own energy to make eggs.
GTS 8 - Triassic
early dinosaurs. MASS EXTINCTION
Continental Drift
movement of continents over time caused by: 1. hot plumes of liquid rock rise from Earth's mantle to the surface and push the continents away from each other 2. where 2 plates collied, one can sometimes slip underneath the other and begin to sink in to the mantle below - eliminates gene flow - affects on survival for animals climate wise
Pre-Zygotic Barriers to Hybridization
one way the species are kept separate. - ecological isolation: breeding in different places or at different times of year or day - behavioral isolation: different courtship displays
Shared Characteristics
organisms share characteristics due to common descent
Geological Time Scale 1 - Precambrian
origin of life, photosynthesis development allows for first eukaryotes and multicellular organisms
GTS 3 - Ordovician
plants began to colonize land. MASS EXTINCTION
Sensory exploitation
predicts that female preference for a trait predates the appearance of the trait in males Ex: swordtail and platyfish. the tail evolved due to female preference
Wynne-Edwards Altruism Theory
proposes the idea of animals conserving their resources for future generations and of group selection: selection acts between populations as well as within them.
Vestigial Organs
reduced or degenerate parts whose function is hard to discern that carry evidence of evolutionary past ex: human tail bones and muscles for moving tail
Order
relative depth or distance from the surface of the Earth at which a fossil is found. corresponds with relative age.
Genetic drift (chance)
the chance of inheriting genes. can cause a loss of genetic variation over time, especially in small populations. - small populations show a greater variation in allele frequency from generation to generation than do large populations. - can lead to fixation: when an allele reaches a frequency of 100% - makes populations more different than each other, while making individuals within each population more similar.
Good genes
the desirable trait is an advertisement for good genes Ex: the peacock that has larger eyespots and their offspring having better chance of survival
Phylogeny
the sequence of events involved in the evolutionary development of a species or taxonomic group of organisms - defined by molecular and physical traits
Sex Ratio
the sex that is the most rare in the population has the higher average reproduction and the higher fitness. ex: 200 offspring from 20 males and 10 females 200/20 = 10, 200/10 = 20. females have an avg. reproduction that is twice as high than males.
Radioisotopes
unstable, radioactive forms of elements that decay to more stable forms at a constant rate over time. help approximate a fossil's age better by measuring the amount of the element and radioactivity left in that fossil.
Adaptive Radiation (Divergent Evolution)
when a group of organisms expands to take on new ecological roles and to form new species and higher taxonomic groups
Adaptively Neutral
when a trait doesn't increase your fitness
Convergent Evolution
when natural selection causes distantly related organisms to evolve similar structures in response to similar environmental changes (analogous features) ex: dolphins and sharks
Allopatric Speciation
when the groups live in different places. - geographic isolation: when a geographic barrier isolates 2 populations of a species - ring species: population found at one end of the geographic range reproduce poorly with the population at the other end
Sympatric Speciation
when the groups live in the same place. - in plants, new species can form with polyploidy: doubling of the number of chromosomes to 4 sets instead of 2 making it to where they can only successfully mate with themselves and not other diploids
