Notes

M O D U L E

-evolution - a change in the frequency of an allele in a population over many generations ("descent with modification" -Darwin)
-theory - an extremely sound conceptual framework that explains numerous observations and experimental results and that generates fruitful scientific hypotheses
-Aristotle (384-322BC) - viewed species as fixed & unchanging; developed Scala Nature & organized life forms on a ladder/scale of increasing complexity
-Carolus Linnaeus (1701-0/0/1778) - developed binomial nomenclature system based on genus + species of organisms; created hierarchical system of nested groups
-James Hutton (1726-0/0/1797) - examined Earth's features, suggested landforms developed from gradual mechanisms of change: erosion
-Jean-Baptiste de Lamarck (1744-0/0/1829) - 1st to suggest how life changes over time; proposed evolutionary change explained fossil evidence & a correlation between organisms + environments; suggested theory of use + disuse (idea that body parts become larger + stronger w/ use and don't deteriorate; Ex: giraffe stretching their neck); suggested inheritance of acquired characteristics (organisms pass modifications to offspring)
-Thomas Malthus (1766-0/0/1834) - suggested plants + animals produce offspring in excess; overpopulation --> disease, famine, war)
-Georges Cuvier (1769-0/0/1832) - noticed some species disappeared, new species appeared (in strata + fossil patterns); OPPOSED evolution, suggested catastrophism (the principle that calamitous events occurred in the past + caused species to die off rather than organisms evolving from a common ancestor)
-Charles Lyell (1797-0/0/1875) - expanded Hutton's ideas & developed principle of uniformitarianism (mechanisms of change are constant over time & continue today)
-Alfred Wallace (1823-0/0/1913) - 1st to propose natural selection; although concluding ideas differed from Darwin's, they both supposed specific adaptions aid in survival of an organism with a particular environment
-Charles Darwin (1809-1882) - theory of evolution strongly influenced by Lyell, Hutton, and Malthus
-conclusions reached during travel:
-members of a population vary in traits they exhibit
-traits inherited from parent to offspring
-all species = capable of producing more offspring than environment can support
-not all offspring of a population will survive to reproduce due to competition for resources (food, space, mates, etc)
-2 specific inferences:
-individuals with inherited traits of higher probability of surviving + reproducing in the environment leave more offspring with those traits than other individuals
-unequal ability to survive + reproduce --> accumulation of specific traits in a given population within a specific environment over the course of several generations
-Darwin's 2 major ideas: descent w/ modification & natural selection
Descent w/ Modification
-states that organisms come from ancestors that lived in past and that had various adaptations based on environment in which they lived
-matched Linnaeus' suggestions that groups of species were interconnected (classification)
-scientific evidence supporting this comes from fossils (evolutionary changes over time), morphology, embryology, & geographic distribution (of species based on continental drift, aka BIOGEOGRAPHY)
Natural Selection
-frequency of advantageous traits increase in # of offspring that survive + reproduce, maintaining the favorable traits for that environment
-misconceptions:
-individuals don't evolve - only populations
-only heritable traits play a role in natural selection (acquired traits not heritable)
-natural selection: based on environment; traits could be favorable in 1 environment & detrimental in another
Adaptions
-adaptation - a trait that makes a living thing better suited for survival in a particular environment
-3 types of adaptations:
-Structural - traits that involve physical structure/anatomy of an organism (ex: size/shape of teeth, body covering, etc.)
-functional - traits that involve internal functions or chemistry of an organism (ex: having enzymes to digest food)
-behavioral - inherited traits that help an organism survive + reproduce in a given environment or responses to the environment (ex: birds laying eggs in nests, migrating, etc.)

T E X T B O O K concept 1

-scala naturae ("scale of nature") - ladder/scale of increasing complexity; every form of life had their OWN rung on the ladder (-Aristotle)
-binomial format for naming species (ex: homo sapiens - humans) (-Linnaeus)
-similar species grouped together instead of each species (-Linnaeus)
-strata - superimposed layers of rock compressed by newer layers of sediment
-paleontology - the study of fossils

T E X T B O O K concept 2

-natural selection (-Darwin) - a process in which individual that have certain inherited traits tend to survive + reproduce at higher rates than other individuals because of those traits

Observations
individuals in a population vary in their heritable characteristics + Organisms produce more offspring than the environment can
support
l/
Inferences
individuals that are well suited to their environment tend to leave more offspring than other individuals
+
over time, favorable traits accumulate in the population

T E X T B O O K concept 3

-homology - similarity resulting from common ancestry
-homologous structures -
-vestigial structures - remnants of features that served a function in the organism's ancestors
-convergent evolution - the independent evolution of similar features in different lineages
-analogous (features) - share common ancestry, but not necessarily similar function
-4 types of evidence for evolution: Direct Observations of Evolutionary Change, Homology (physical similarities), Fossil Record, Biogeography
-biogeography - the scientific study of the geographic distributions of species (continental drift + Pangaea)
-endemic - found nowhere else in the world









M O D U L E
ALL LISTED W/OUT "*" ARE DEDUCED; "*" SHOWS THAT IT'S COMPLETELY RIGHT

-Earth + other planets in solar system formed 4.6 billion years ago (from clouds + dust surrounding the sun)
-1st few million yrs: earth struck w/ rock + ice, creating enough heat to vaporize water
-as space-matter-collisions decreased, elements rearranged themselves according to density
-earth's atmosphere was made up of HCN, CO2, CO, N2, H2S, + H2O vapor
-~= 3.8 billion yrs ago, water vapor condensed to liquid
-large organic molecules formed protobionts
-protobionts - large organic molecules formed which acted like pre-cells
-exhibit some properties of life (reproduction + metabolism)
-first working cells = prokaryotes
-small pieces of RNA formed + replicated, creating DNA system (protein synthesis)
-microfossils --> 1st forms of life were anaerobic
-photosynthetic prokaryotes evolved, O2 gas released into the atmosphere
-when respiration came around for some, the poison in O3 drove organisms to extinction
-Geologic Time Scale - timeline that uses certain divisions to represent evolutionary time (marked w/ major changes found in fossil record)
-Archaean + Proterozoic - 1st 2 eons (4 billion yrs)
-Phanerozoic - last eon (remaining 1/2 billion yrs): (they are "*" bc they are names created by humans
-*Paleozoic eon (ancient) - many vertebrates + invertebrates lived b
-*Mesozoic (middle) - age of dinos c
-*Cenozoic (recent) - age of mammals Eras further divided into periods (10,000,000 yrs - <2,000,000 yrs)
-cyanobacteria - photosynthetic bacteria (brought gradual rise in atmospheric O2 levels)
-endosymbiosis - model that suggests mitochondria + plastids were once small prokaryotes that began living within larger host cells
-Endosymbiotic theory (video):
1. nucleolis surrounded by enfolding membrane, creating nucleus
2. enfolding membrane --> endoplasmic reticulum
3. cell engulfed aerobic bacteria --> mitochondria
4. cell w/ mitochondria engulfed photosynthetic bacteria --> chloroplast
-chloroplast + mitochondria: have DNA, may be leftover genome and may have been smaller independent bacteria

T E X T B O O K

-macroevolution - the broad pattern of evolution above the species level

T E X T B O O K concept 1

-4 main stages that produced cells:
1. the abiotic synthesis of small organic molecules (ex: amino acids, nitrogenous bases)
2. the joining of these small molecules into macromolecules (proteins, nucleic acids, etc)
3. the packaging of these molecules into protocells
-protocells - droplets w/ membranes that maintained an internal chemistry different from that of their surroundings
4. the origin of self-replicating molecules that eventually made inheritance possible
-Earth
-formed 4.5 billion yrs ago
-collisions of huge rocks and ice generated enough heat to vaporize all available water on Earth (ended 4 billion yrs ago)
-Oparin-Haldane hypothesis - Earth's early atmosphere was a reducing (electron-adding) environment, in which organic compounds could have formed from simpler molecules
-another hypothesis: organic compounds were 1st produced in deep-sea hydrothermal vents
-hydrothermal vents (black smokers) - areas on the seafloor where heated water + minerals gush from Earth's interior into the ocean
-alkaline vents - other deep-sea vents that release water that has a high pH (9-11) & is warm (40-90°C) rather than hot (environment more suitable for origin of life)
-another possible source of organic molecules: meteorites
-necessary conditions for life may have been met in vescicles
-vesicles - fluid-filled compartments enclosed by a membrane-like structure
-can form spontaneously when lipids/other molecules are added to water
-ribozymes - RNA catalysts/molecules that function as enzymes
-RNA replication --> DNA --> DNA replication --> beginning of life and history

T E X T B O O K concept 2

-fossil record based primarily on the sequence in which fossils have accumulated in strata
-strata - sedimentary rock layers
-radiometric dating - a radioactive "parent" isotope decays to a "daughter" isotope at a characteristic rate
-half-life - the time required for 50% of the parent isotope to decay
-each type of radioactive isotope has an half-life, not affected by environmental variables (temperature, pressure, etc)
-CHECK OUT PAGE 525 for SKULL PARTS COMPARISON BETWEEN ANIMALS

T E X T B O O K concept 3

-geologic record - a standard time scale that divides Earth's history into 4 eons & further subdivisions
1st 3 eons: Hadean + Archaean + Proterozoic = 4 billion years
-phanerozoic eon (last 1/2 billion years): encompasses most of the time that animals have existed on Earth
-3 eras: Paleozoic, Mesozoic, and Cenozoic
-CHECK OUT PAGE 526 AND 527 FOR ERA/EON DIAGRAMS
-earliest direct evidence of life (3.5 billion years ago): stromatolites
-stromatolites - layered rocks that form when certain prokaryotes bind thin films of sediment together
-they and prokaryotes where Earth's sole inhabitants for > 1.5 billion years
-chronology evidence of O2 left in rusting of iron-rich rocks implies that today's cyanobacteria originated before 2.7 billion years ago
-cyanobacteria - oxygen-releasing, photosynthetic bacteria
-oldest widely accepted fossils of eukaryotic organisms = 1.8 billion years old
-cytoskeleton allows it to change shape/engulf other cells
-endosymbiont theory - mitochondria + plastids (a general term for chloroplasts + related organelles) were formerly small prokaryotes that began living within larger (host) cells
-serial endosymbiosis - supposes that mitochondria evolved before plastids through a sequence of endosymbiotic events (because eukaryotes don't have plastids/chloroplasts)
-Ediacaran biota - larger multicellular fossils that were soft-bodied organisms
-Cambrian explosion - a relatively brief time in geologic history when many present-day phyla of animals 1st appeared in the fossil record
-roughly 450 million years ago, arthropods were among 1st animals to colonize land

T E X T B O O K concept 4

-plate tectonics - theory in which the continents are part of greater plates of Earth's crust that essentially float on the hot, underlying portion of the mantle
-continental drift - a process in which the tectonic plates move, over time, caused by movements in the mantle
-Pangaea was formed 250 million years ago
-mass extinction - large numbers of species become extinct worldwide
-CHECKOUT PAGE 534-535 FOR A BRIEF OVERVIEW OF MASS EXTINCTION EFFECTS
-adaptive radiations (pg 536) - periods of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles (niches) in their communities

T E X T B O O K concept 5

-heterochrony - an evolutionary change in the rate or timing of developmental events
-paedomorphosis - the retention in an adult organism of the juvenile features of its evolutionary ancestors
-homeotic genes - master regulatory genes that determine such basic features as where a pair of wings + legs will develop on a bird or how a plant's flower parts are arranged
-products of 1 class of homeotic genes = Hox genes, which provide positional info in an animal embryo

T E X T B O O K concept 6

-exaptations - structures that evolve in 1 context but become co-opted (?) for another function









M O D U L E

-microevolution - the change of allelic frequency in a population over generations
-3 main mechanisms that cause microevolution: natural selection, genetic drift, and gene flow
-genetic variation - the variety in alleles of genes (DNA sequences) within & among populations
-quantitative traits - coded by many genes
-discrete traits - coded for by 1 or fewer genes
-mutations - any change in the nucleotide sequence of an organism's DNA (ultimate source for new alleles ina gene pool)
-point mutations - change a single base pair in a gene --> significant change in expressed phenotype
-chromosomal mutations - change or even delete many genetic loci at once; almost always harmful
-factors of sexual reproduction contribute to genetic diversity
-crossing over
-independent assortment of chromosomes
-random fertilization
-natural selection - the concept that individuals in a population exhibit variation in their heritable traits, & those organisms w/ traits that are best suited for the environment tend to produce more offspring than those who are less well suited
-3 ways it alters frequency distribution of heritable traits:
1. stabilizing selection - favors intermediate phenotypes (heterozygous traits are mixed; ex: red + white = pink)
2. directional selection - favors 1 extreme or the other
3. disruptive selection - favors extreme phenotypes (opposite of stabilizing; pink = red + white)
-genetic drift - evolution occurring through random changes in allele frequency within a gene pool due to chance
-*when # of individuals carrying an allele changes in a large population, the frequency of the allele doesn't change dramatically; impact of random changes in small population is much greater*
-bottleneck effect - results from a drastic reduction of a population (often caused by catastrophic event)
-founder effect - results from a small populations colonizing an area away from the larger population
-gene flow - the gain or loss of alleles from a population caused by the immigration/emigration of individuals

K H A N V I D E O

-evolution: natural selection, genetic drift
-genetic drift: random changes, more likely w/ small populations
-bottleneck effect
-founder effect

T E X T B O O K

-microevolution - evolution on its smallest scale; a change in allele frequencies in a population over generations

T E X T B O O K concept 1

-many differences occur within introns
-introns - noncoding segments of DNA lying between exons
-exons - the regions retained in mRNA after RNA processing

T E X T B O O K concept 3

T E X T B O O K concept 4

M O D U L E

-species - a group of organisms whose traits are so similar that they can successfully amte w/ each other & produce viable, fertile offspring
-speciation - the evolution of a new species that occurs when 2 similar reproducing being evolve to become too dissimilar to share genetic info or produce viable offspring
-categories of speciation based on factors of reproduction/reproductive isolation
-reproductive isolation - existence of biological barriers that prevent members of 2 species from producing viable, fertile offspring
-prezygotic barriers - impede reproduction by preventing male + female sex cells from uniting based on physical or behavioral factors
-habitat isolation - can't overcome physical barriers of environment to mate
-temporal isolation - flowers bloom at different times of the year won't fertilize on each other
-behavioral isolation - courtship + mating rituals won't recognize potential mates
-mechanical isolation- reproductive structures that are incompatible aren't able to achieve fertilization
-gametic isolation - sperm is unable to penetrate egg --> no fertilization can occur
-postzygotic barriers - occur after the egg is successfully fertilized + has developed into a zygote
-reduced hybrid viability - hybrid embryos don't develop correctly
-reduced hybrid fertility - hybrid adults = sterile or infertile
-hybrid breakdown - hybrid adults = feeble or don't survive
-allopatric speciation - when gene flow is interrupted and a population is divided into geographically isolated subgroups (can be caused by earthquakes, storms, canyons). Over time, the 2 subgroups evolve differently, creating 2 different species
-sympatric speciation - occurs if gene flow is reduced by polyploidy, habitat differentiation, or sexual selection
-polyploidy - a condition that occurs in cell division that results in cells w/ extra sets of chromosomes (> diploid; ONLY in plants; --> reproductive isolation from original population, but perpetuation of new species thru self pollination
-habitat differentiation - when factors influence the resources for a subgroup of the population (shelter or food)
-sexual selection can also drive sympatric speciation when mate selection changes for a subgroup within the population
-biodiversity -
-biological resistance: organisms that develop resistance to disease, pesticides, or antibiotics due to genetic mutations









M O D U L E

-Hardy-Weinberg principle - both allele + genotype frequencies in a population remain constant from generation to generation if the population remains in the same equilibrium
-conditions: random mating, no mutations, no natural selection, large population size, no genetic drift/gene flow, population = large in # (used only as a baseline/control)
-Hardy-Weinberg equilibrium equation - a simple equation that can be used to discover the probable genotypic frequencies in a population nad to track their changes from 1 generation to another
p^2 + 2pq + q^2 = 1
p = frequency of dominant allele in gene pool
q = frequency of recessive allele in gene pool
p^2 = % of homozygous dominant individuals
q^2 = % of homozygous recessive individuals
2pq = % of heterozygous individuals (in the population)
p + q = 1

L I V E S E S S I O N

-because most organisms are diploid, 2 times the population = total # of alleles
(# dominant alleles x 2 + heterozygous alleles)/total # alleles = dominant allele frequency
(# recessive alleles x 2 + heterozygous alleles)/total # alleles = recessive allele frequency
-Hardy-Weinberg equilibrium:
-sexual reproduction:
-does NOT change population allele frequencies
-creates genetic variety in individuals, not population
-"shuffling a deck" analogy
-requirements:
1. no gene flow (emigration or immigration)
-gene flow - organisms will enter or exit a population; organisms of the same species (to interbreed) (gene flow =
2. no mutations occur (mutations are a force of evolution)
3. no natural selection occurring (natural selection = force of evolution
-directional - population mean is moving towards 1 direction or the other (anteater snout length)
-disruptive - both extremes are selected for (not intermediates) (blending in) (limpet shell coloration)
-stabilizing - mean is selected for (child birth weight)
4. population = large in #
-genetic drift - any random change in allele frequency
-no genetic drift (because the greater the population, the smaller the genetic drift, vice versa)
-genetic drift:
-bottleneck effect - natural disaster kills many organisms, survivors
-founder effect - very small population isolated from larger population in new area (ex: islands)
-genetic drift tends to REDUCE variety
-allele frequency changes for genetic drift = very random
-small population --> genetic drift wipes out entire alleles from population --> genetic variation decreases --> lowers population --> eventually, extinction
5. mating = random among population members (sexual selection = last force of evolution)
-Hardy-Weinberg equations:
-allele (frequency) equation: p + q = 1
-organism ("phenotype"/"genotype"/"individuals") equation: p^2 + 2pq + q^2 = 1
-allele = the "R" or "r" in "Rr" out of a population
-allele = the "RR", "Rr", or "rr" out of a population