Chapter 18 & 19 Flashcards
(27 cards)
Four Overlapping Stages
- origin of organic molecules
- organic polymers
- formation of boundaries
- RNA world
Chemical Selection
a chemical within a mixture has special properties that cause it to increase in number compared to other chemicals in the mixture
Fossil
preserved remains of past life on earth
-radioisotope dating
Origins of Eukaryotic cells
hypothesized to involve a union between bacterial & archaeal cells
Biological Evolution
heritable change in one or more characteristics of a population or species from one generation to the next
Species
group of related organisms
Evidence of Evolutionary Change
fossil records biogeography convergent evolution selective breeding homologies
Population
group of individuals of the same species that occupy the same environment & can interbreed with one another
Gene pool
all the alleles for every gene in a given population
Allele frequency
the number of copies of a species allele in a population divided by total number of all alleles for that gene in a population
Genotype frequency
number of individuals with a particular genotype in a population divided by total number of individuals in a population
Fitness
relative likelihood that one genotype will contribute to the gene pool of the next generation compared with the other genotypes
Natural Selection Patterns
Directional selection
stabilizing
disruptive
balancing
Genetic drift
change in allele frequencies due to random change
Migration & Nonrandom mating
gene flow occurs when individuals migrate between populations having different allele frequencies
Origin of organic molecules
nucleotides & amino acids were produced prior to the existence of cells
Organic Polymers
nucleotides became polymerized to form RNA & DNA, & amino acids become polymerized to form proteins
Formation of boundaries
polymers become enclosed in membranes
RNA world
polymers enclosed in membranes acquired cellular properties
Natural Selection
more offspring produced than can survive
compete for limited resources
individuals with better traits flourish & reproduce
Biogeography
unique species found on islands & other remote areas
Convergent evolution
2 different species from different lineages sometimes become anatomically similar b/c they occupy similar environments
Homologies
similar structures due to descent from a common ancestor
Directional selection
individuals at one extreme of a phenotype range have greater reproductive success in a particular environment
