History of Biological Diversity

 Preserved evidence of organism  Learned different types of fossils ◦ Molds, casts, petrified fossils, animal & plant remains & trace fossils ◦ Geologic time scale – eras, periods ◦ Relative age of rocks – half -life  Carbon-14 dating

 Hereditary changes in groups of living organisms over time

 Anatomy – study of structure ◦ If the diverged from a common ancestor they have similar characteristics (homologous structures)  > the # of shared structures btw 2 species, the more closely related they are ◦ Vestigial organs (little or no function to the organism) are often homologous w/ structures in related species that still work ◦ Species living in diff locations under similar ecological conditions, dvlp similar structures & behaviors  If conditions change, those w/ favorable anatomical traits become established

 Embryology – embryonic dvlpt or organisms ◦ pre-birth, pre-hatching, or pre- germination ◦ Can see similarities not seen in adults b/c adults change form ◦ Similar embryonic structures means common ancestry

 Biochemistry – genes & proteins ◦ More similar the DNA & amino acid seq, the more likely they are to have a common ancestor ◦ Better than anatomy  When species are so closely related they don’t appear to be diff  When species are so diverse they share few similar structures

 Paleontology – prehistoric life ◦ Fossil record gives evidence of life forms & envir ◦ Supports evolutionary relationships  Shows a pattern of gradual change ◦ Not complete – gaps ◦ The older the fossil, less resemblance to modern version

 Defined as the evolutionary history of a species or a grp of related species  Dvlpd evolutionary theory that states that all forms of life on Earth are related b/c there is a common ancestor

 Anatomy – similarity means a common ancestor ◦ Divergence – acculum. of evolutionary differences  May be homologous in structure but not function ◦ Convergence – structures w/ diff evolutionary histories become more similar over time to adapt to a similar envir (analogous structures)  Embryology – highly divergent taxa (grps) w/ so many anatomical diff ◦ ontogeny (growth & dvlpt of an indiv organism) will recapitulate phylogeny

 Paleontology – gives info on dates & order of divergence ◦ Transitional fossils – show links in traits btw grps for documenting intermediate stages of a species’ evolution  Biochemistry – molecular clock - > the genetic similarity, more recent is the common ancestor ***1 piece of evidence doesn’t give an accurate pic of the evolution of 1 species – evidence from all the fields gives more reliable info

 Hard to classify b/c species are becoming extinct  Most recent classification: ◦ 3 Domains – Domain Archae, Domain Bacteria, Domain Eukarya ◦ 6 Kingdoms – Kingdom Eubacteria, Kingdom Archaebacteria, Kingdom Protista, Kingdom Fungi, Kingdom Plantae, Kingdom Animalia

 All the changes that have transformed life on Earth  Can occur on a small scale affecting a single population (microevolution) or large scale affecting species across populations (macroevolution)

 Occurs b/c indiv of a pop have diff traits that allow them to be more or less effective in an envir than other members  Changes in inherited traits over time – increases a species’ “fitness” in its envir.

1. Overproduction of Offspring: ◦ raises the chance that some will survive but also inc competition for resources

2. Variation: ◦ exists w/in the inherited traits in the phenotypes (which is controlled by the genotypes & the envir) ◦ All life that has ever existed on Earth, least nucleic acids (DNA or RNA) and proteins ◦ 2 types of reproduction:  Sexual – meiosis creates gametes, fertilization takes place creating variation  Asexual – 1 parent that produces a clone (binary fission or mitosis) – ex.) budding, fragmentation & vegetative propagation – repro rate is higher but in a changing envir can’t adapt

 If you could reproduce sexually & asexually, better advantage for survival!!!!

3. Adaptation: ◦ increased frequency of a particular structure, physiological process or behavior in a pop that makes it better able to survive & reproduce ◦ Gene pool changes over time b/c those less adapted will die ◦ “fitness” – measure of how a trait contributes to repro success SURVIVAL OF THE FITTEST!!!!

4. Descent w/ Modification: ◦ as the envir of a pop changes, the entire process of natural selection yields pop w/ new phenotypes ◦ over time pop will have diff structures, live in diff niches or habitats than ancestors

 Species – grp of organisms that share similar characteristics & can interbreed w/ 1 another to produce fertile offspring  Means they share a common gene pool (all genes of all the indivs in a pop)  So a genetic change in 1 indiv can spread through a pop through mating ◦ If the change inc fitness, then more indiv will have it

 So the greater the diversity, the greater the chances for the species to survive  Favorable traits in male & female organisms enhance repro. success ◦ Non-random mating changes the gene pool over time & a better adapted species  Inherited beneficial traits become more prevalent, & detrimental traits become less

 Genetic Drift – random change in allele frequency ◦ Rare alleles dec in freq & are eliminated ◦ Other alleles inc & become fixed ◦ Seen more in small pop vs large pop  Gene Flow – movemt of genes in & out of a pop – due to migration  Non-random Mating – limits the freq of some alleles

 Mutations – inc freq & types of allele changes in a pop  Natural Selection – allows most favorable phenotypes to survive & be passed on

 When there is no change in allele freq, pop is in genetic equilibrium  5 conditions: ◦ Large population ◦ No movement in or out of pop ◦ Random mating ◦ No mutations ◦ No natural selection

 Process of forming a new species by biological evolution from a pre-existing species  Usually a result of isolation (reproductive or temporal, behavioral, geographic)  As different traits become favorable the 2 pop gradually become so different they are unable to reproduce w/ each other

 Gradualism – slow changes over a period of time  Punctuated Equilibrium – periods of abrupt changes after periods of little change  Adaptive Radiation/Divergent Evolution - # of different species split off from a common ancestor – survive in different niches  Convergent Evolution – occur among different species living in similar envir – produce analogous structures

 Coevolution – 2 or more species living in close proximity change in response to each other  Extinction – elimination of a species b/c they can’t adapt – can be gradual or rapid ◦ Gradual Extinction – slow rate due to other organisms, changes in climate or natural disasters ◦ Mass Extinction – result of catastrophic events that change the envir very suddenly