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Biology Exam, extinction, Sympatric speciation is when there is speciation…

- - - - for all of life we all came from LUCA and diverged into the 3 main monophyletic groups of: bacteria archaea, eukarya
      - the 3 groups of mammals are placentals (outside Australia), monotremes (platypus) and marsupials (high concentration in Australia, kangaroo)
        
        separated by Huxley, Wallace and Lydekker
        
        mammals all have hair and lactate, this is a synapomorphy
        
        synapomorphy is a trait that organisms have that do not exist outside of the clade
        
        maximum parsimony is the path that has the least changes
      - homology: shared traits from a shared ancestry
        
        homoplasy: shared traits but not because of a shared ancestry, this is because of convergence, rather than divergence
        
        adaptive radiation: the evolution of traits separately, the four factors to consider it to be adaptive radiation is the evolutionary history, the environmental-phenotype conditions, the traits function, and the rapid speciation
        
        an example of biological innovation is cichlid fish
        
        example of environmental opportunity is the anoles lizard
        
        genetic homology: same genes
        
        developmental homology: seen in the embryos
        
        structural homology: similarity seen in the morphology
      - transitional trait is an intermediate trait inbetweem ancestral and derived species
        
        vestigial trait: traits that once served a purpose but are now useless, appendix, coccyx, eyes of a blind mole rat, foot bones in a whale
    - - fitness is reproduction not survival
        
        sexual selection: a trait that increases an individuals likelinesss to reproduce. these are heritable traits
        
        females are choosy of their males
        
        males have greater variation in reproduction than females
        
        females choose males with better heritable traits, attractiveness, and parental care because the women is putting a lot more energy into the egg than a Mae is putting into his sperm
        
        isogamous is equal contribution, there is no sexual selection in these species
        
        results in male-male competition, sexual dimorphism, violates HWE, and more male parenting
        
        Sexual cannibalism: benefits include nutrition for the female, no mistaken identity, mechanism of rejection
        
        non-random matiing
        
        adaptation is a characteristic that increases the fitness of an individual
      - acclimization is chases made in the lifetime, these are not passed down, meaning they are not heritable
      - artificial selection is a type of natural selection but is not so natural because it is from humans. this could be intended such as prepping plants and animals, or this could be unintended (sheep horns)
    - - mutations: random different, generates new alleles, slow and takes a long time, we have a lot of mutations that o unnoticed, to examine it is best to look at them with short generation times
      - something that does not change the allele frequency but changes the genotype frequency is inbreeding - this increases the homology of genotypes and will usually result with recessive mutations, heterozygosity is beneficial
        
        example of advantageous heterozygosity would be for sickle cell anemia, you have something against malaria
      - genetic drift is the changes due to chance, this is unbiased with respect to fitness, can lead to random loss or fixations of alleles, small populations are susceptible to it, this is a reason that Javan rhino lost genetic diversity
        
        founder effect: colonization of a new area, and then we have the bottleneck effect where there is a contraction in the population and with that some alleles are lost
      - gene flow: movement of alleles from one population to another, brings new allele into a population that has variation, you are reducing the genetic variation between populations because you are mixing them
        
        when the gene flow reduces the differences between the populations, this is called homogenization
        
        when this is advantageous it is called adaptive introgression
- - - - prezygotic isolation:
        
        gamete?: the sperm and eggs are incompatible
        
        behavioural: two species have different courtship behaviour
        
        mechanical: incompatible genitalia
        
        temporal: breeding season is at different times
        
        habitat: habitats are isolated from each other
      - post zygotic isolation:
        
        the offspring matures but it is sterile
        
        the offspring cannot mature and dies as an embryo
- - - - Primates: have adaptations for swining and climbing, they have larger brains, opposable thumbs and prehensile tails, they are hind-limb dominant, they have stereoscopic vision, and they have nails instead of claws
        
        different primates have different social systems. Gibbons are monogamous, orang-utans are more solitary, chimps are multi male multi female, male dominated, clans. gorillas have a silverback and harem, infanticide, bonobos have a lot of sex, strong female-female bonds and they are female dominated
        
        ancestral traits of primates include small molars, large brow ridge, small brain case, large canines. the traits that have been derived are small canine (smaller than chimps), flatter face, forward movement of the form magnum
        
        along with homosapiens there was neanderthals which had adaptations for the cold as well as were a lot stockier than humans, but Denisovans were closer to them and did not share much breeding together but they had some. neanderthal genes involved with coping with UV radiation, risked depression, hyper coagulation, tobacco use
        
        loved in europe, western Asian southern siberia, non-africana modern humans shared 1-4% of their genome, but not ones from africa, but these are not all of the same. together we have found a fifth of the neanderthal genome
        
        suspensory motion adaptations include longer arms, stiff spine, grasping hands, opposable thumbs, shoulder and other joints , loss of tail, strong pelvic floor
        
        primates have complex foraging techniques that have led to: longer juvenile periods, larger life expectancy, and larger brains
        
        when they share food roles, then there is less male-male competition and there is less sexual dimorphism
        
        traits that have allowed for bipedalism in humans: narrow feet with a bigger big toe, flared pelvic bone, knees go inward, hole at the base of the cracium allowing for a straight spine
        
        humans differ from other apes with their increased juvenile dependence, there creative and symbolic thought, larger brains, full bipedalism, and differing dimorphism
        
        Types of primates
        
        prosminans: these have large ears, nocturnal, reflective eyes
        
        tarsiers; large eyes - the size of the brain, long feet and toes, good hearing
        
        new world monkeys: these are monogamous, tails, non opposable thumbs
        
        old world monkeys/apes: sexual dimorphism, no tails