Download Evolution Guided Notes

 EVOLUTION -­‐NOTES-­‐ DESCENT WITH MODIFICATION •
Evolution-­‐ descent with modification; change in the ____________________________________ of a population from generation to generation. •
_____________________________________________-­‐ founder of taxonomy; developed the binomial system of naming species •
Paleontology-­‐ study of fossils (_____________________) •
______________________________________-­‐ the principle that events in the past occurred suddenly and were caused by mechanisms different from those operating in the present. •
______________________________________-­‐ mechanisms of change are constant over time. •
____________________________-­‐ hypothesized that species evolve through ___________________ of body parts and the inheritance of ______________________________________________________. ADAPTATIONS AND NATURAL SELECTION •
_____________________________-­‐ characteristics of organisms that enhance their survival and reproduction in specific environments. •
_____________________________________________-­‐ how adaptations arise; a process in which individuals with certain inherited traits leave more offspring than individuals with other traits. DARWIN’S OBSERVATIONS/INFERENCES •
Individuals whose inherited traits give them a higher probability of surviving and reproducing in a given environment tend to leave more ______________________________ than other individuals. •
This unequal ability of individuals to survive and reproduce will lead to the accumulation of _____________________________________ in the population over generations. www.brownbiology.com DATA FOR EVOLUTION •
_____________________________________________________________________ o predator/prey relationships o drug-­‐resistant HIV •
_________________________________ •
_________________________________ o Similarity resulting from common ancestry. •
_________________________________ o The geographic distribution of species. •
___________________________________________________-­‐ variations on a structural theme that was present in their common ancestor. EVOLUTIONARY TREES www.brownbiology.com CONVERGENT EVOLUTION •
The __________________________ evolution of similar features in different lineages. •
Analogous resemblance results from convergent evolution. EVOLUTION AND VARIATION •
Microevolution-­‐ small scale evolution; change in _______________________________________ in a population over generations. •
________________________ Characters-­‐ classified on an either-­‐or basis •
_________________________________ Characters-­‐ vary along a continuum •
____________________________________________________-­‐ (gene variability) the average percent of loci that are heterozygous. •
________________________________________________________-­‐ comparing DNA sequences of two individuals. •
____________________________________________________-­‐ differences in genetic composition of separate populations. MUTATIONS •
Mutation-­‐ the ultimate source of ______________________________________ •
Point mutations-­‐ a change in one base in a gene •
Neutral and Beneficial Mutations •
Mutations Rates o Plants/Animals-­‐ 1/100,000 genes per generation o Prokaryotes-­‐ fewer mutations, shorter generation span, more genetic variation o Viruses-­‐ more mutations, shorter generation span, RNA genome with fewer repair mechanisms GENE POOLS AND ALLELE FREQUENCY •
_________________________________-­‐ a group of individuals of the same species that live in the same area and interbreed, producing fertile offspring. www.brownbiology.com •
_________________________________-­‐ all of the alleles for all the loci in all individuals of the population. o ____________________-­‐ only one allele exists for a particular locus and all individuals are homozygous for that allele HARDY-­‐WEINBERG PRINCIPLE •
H-­‐W Equilibrium describes a _______________________________________________________________ within a gene pool. o p2 + 2pq + q2 = 1 §
where p2 and q2 represent the frequencies of the homozygous genotypes and 2pq represents the frequency of the heterozygous genotype HARDY-­‐WEINBERG ASSUMPTIONS 1. ______________________________________________________________________ 2. ______________________________________________________________________ 3. ______________________________________________________________________ 4. ______________________________________________________________________ 5. ______________________________________________________________________ *Departure from any of these conditions usually results in evolutionary change. MECHANISMS THAT ALTER ALLELE FREQUENCY •
____________________________________________ o Leads to ______________________________________________ •
______________________________________-­‐ chance events that cause allele frequencies to fluctuate unpredictably from one generation to the next. o _______________________________________-­‐ occurs when a few individuals become isolated from a larger population. This smaller group may establish a new population whose gene pool and allele frequencies differ from the source population. www.brownbiology.com o ____________________________________________-­‐ a sudden change in the environment such as a fire or flood, may drastically reduce the size of a population. •
________________________________-­‐ the transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes EFFECTS OF GENETIC DRIFT 1. Genetic drift is significant in _______________ populations 2. Genetic drift causes _________________________________________________ to change at random 3. Genetic drift can lead to a loss of ____________________________________ within populations 4. Genetic drift can cause harmful alleles to become __________________ NATURAL SELECTION AND ADAPTIVE RADIATION •
_________________________________________-­‐ the contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals. •
Natural selection is the only evolutionary mechanism that continually leads to adaptive evolution. DIRECTIONAL SELECTION •
Occurs when conditions favor individuals exhibiting ___________________________________ of a phenotypic range, thereby shifting the frequency curve for the phenotypic character in one direction or another. DISRUPTIVE SELECTION •
Occurs when conditions favor individuals at _________________________________ of a phenotypic range over individuals with intermediate phenotypes. www.brownbiology.com STABILIZING SELECTION •
Acts against both extreme phenotypes and favors _____________________________________________________. OTHER SELECTION •
___________________________________________ o a form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates. •
____________________________________________ o marked differences between the two sexes in secondary sexual characteristics, which are not directly associated with reproduction or survival. •
_____________________________________________ o Selection within the same sex. Individuals of one sex compete directly for mates of the opposite sex. •
_____________________________________________ o “mate choice”-­‐ individuals of one sex (usually females) are choosy in selecting their mates from the other sex. PRESERVATION OF GENETIC VARIATION •
________________________ o Hides genetic variation from selection in the form of recessive alleles •
____________________________________________ o Occurs when natural selection maintains two or more forms in a population. •
____________________________________________________ o Individuals who are heterozygous at a particular locus have greater fitness than do both kinds of homozygotes •
_____________________________________________________________ o The fitness of a phenotype declines if it becomes too common in the population www.brownbiology.com •
____________________________________________ o Has no selective advantage or disadvantage WHY NATURAL SELECTION CANNOT FASHION PERFECT ORGANISMS •
Selection can only act on ________________________________________________. •
Evolution is limited by historical constraints. •
Adaptations are often __________________________________. •
Chance, natural selection, and the environment interact. THE ORIGIN OF SPECIES •
_____________________-­‐ the process by which one species splits into two or more species •
Microevolution-­‐ changes over time in allele frequencies in a population •
Macroevolution-­‐ the broad pattern of evolution over long time spans BIOLOGICAL SPECIES CONCEPT •
______________________-­‐ a group of population whose members have the potential to interbreed in nature and produce viable, fertile offspring. •
_____________________________________________-­‐ the existence of biological factors (barriers) that impede members of two species from producing viable, fertile offspring. o ___________________________ Barriers o ___________________________ Barriers OTHER DEFINITIONS OF SPECIES •
_________________________________________ Species Concept-­‐ characterizes a species by body shape and other structural features. •
___________________________ Species Concept-­‐ views species in terms of their ecological niche. •
______________________________________ Species Concept-­‐ defines a species as the smallest group of individuals that share a common ancestor. *more than 20 other species definitions have been proposed www.brownbiology.com TYPES OF SPECIATION •
____________________________ Speciation o A population forms a new species while geographically isolated from its parent population •
___________________________ Speciation o A small population becomes a new species without geographic separation. •
Adaptive Radiation o Creates a better match between organism and environment. AUTOPOLYPLOIDY VS. ALLOPOLYPLOIDY www.brownbiology.com REPRODUCTIVE ISOLATION •
________________________________-­‐ a region in which members of different species meet and mate. o ___________________________________-­‐ strengthening reproductive barriers o ___________________-­‐ weakening reproductive barriers o ________________________-­‐ continued formation of hybrid individuals SPECIATION •
____________________________________________________-­‐ periods of apparent stasis punctuated by sudden change. THE HISTORY OF LIFE ON EARTH •
___________________________________-­‐ the pattern of evolution over large time scales. •
Earliest evidence of life: _____________________________________ •
How did the first living cells appear? o ____________________________________________ of small organic molecules o Joining of these molecules into _________________________________ o Packaging of these molecules into _______________________________ o Origin of _______________________________________________________________ that made inheritance possible www.brownbiology.com SYNTHESIS OF EARLY EARTH •
Formed about _________________ billion years ago •
Oparin and Haldane-­‐ __________________________________________ •
___________________________________________-­‐ tested Oparin and Haldane hypothesis in lab-­‐ produced multiple amino acids and other organic compounds •
______________________________________-­‐ collections of abiotically produced molecules surrounded by a membrane-­‐like structure FOSSIL RECORD •
Absolute Dating o _____________________________________________________-­‐ based on the decay of radioactive isotopes o ___________________________________-­‐ the time required for 50% of the parent isotope to decay. •
Challenges o Organisms do not use radioisotopes that have long half-­‐lives. o Sedimentary rocks have compounds of different ages. THE GEOLOGIC RECORD •
Geologic Record-­‐ divided into three ______________ ◦
Archaean ◦
Proterozoic ◦
Phanerozoic-­‐ the last half billion years-­‐ divided into three ____________ –
Paleozoic –
Mesozoic –
Cenozoic FIRST ORANISMS •
____________________________________-­‐ layered rocks that form when certain prokaryotes bind thin films of sediment together. www.brownbiology.com •
_______________________________________-­‐ mitochondria and plastids took residence inside a prokaryote to form a eukaryote o Evidence •
§
Mitochondria and chloroplasts have own ___________ §
_________________________________ §
Mitochondria and chloroplasts _____________________________________________ ______________________________________________________-­‐ many phyla of living animals appear suddenly in fossils formed early in the Cambrian period (535-­‐525 mya) •
_____________________________________________-­‐ the movement of Earth’s plates, over time. o Supercontinent-­‐ formed three times •
_________________________________________________-­‐ large number of species become extinct throughout Earth. o Consequences: disrupt a thriving ecological community, disappearance of evolutionary lineage Evolution is like tinkering-­‐ a process in which new forms arise by the slight modification of existing forms. Even large changes, like the ones that produced the first mammals, can result from the gradual modification of existing structures or the slight modification of existing developmental genes. -­‐Francois Jacob (modified) www.brownbiology.com