3: Modern Evolutionary Theory and Systematics Flashcards
darwins main weakness
inability to identify mechanisms of inheritance
alternative forms of a gene
allele
combination of alleles (hereditary types)
genotype
visible characteristics of an organism
phenotype
3 mendelian laws of inheritance
- law of dominance
- law of segregation
- law of independent assortment
mendelian law: in a heterozygote, one allele would mask the phenotype of the other
law of dominance
allele expressed in both homozygous and heterozygous individuals
dominant allele
allele only expressed if the individual is homozygous for that allele
recessive
mendelian law: paired alleles that specify alternative phenotypes separate so each gamete receives only one allele
law of segregation
mendelian law: genes found on different pairs of homologous chromosomes assort independently during meiosis
law of independent assortment
some genes that don’t follow mendelian laws
(ex: multiple alleles, sex-linked inheritance)
non-mendelian inheritance
study of genetic change occurring within natural populations
microevolution
occurence of different forms of an allele in a population
polymorphism
all alleles of all genes possessed by members of a population
gene pool
measures the relative frequencies of different alleles in a population
population genetics
random fluctuation in allele frequencies from one generation to the next
genetic drift
movement of alleles between populations via migration
gene flow
describes large scale events in evolution
macroevolution
encompasses the differential survival and multiplication of species based on variation among lineages
species selection
selection where mass extinctions may select for different characteristics from those that were common during non extinction events
catastrophic species selection
science of classificaiton
taxonomy
first person to group organisms based on their shared morphological features
aristotle
created the first unified system for classifying animals and plants through morphology
carolous linnaeus
major groups of orgnisms
taxa
main taxonomin ranks
domain
kingdom
phylum
class
order
family
genus
species
commonly used criteria among species concepts:
- common descent
- smallest distinct groupings
- reproductive community
species present over large geographic ranges
cosmopolitan species
species concept: refers to a species as an interbreeding population
biological species concept
species concept: defines species by fixed, essential features
morphological species concept
species concept: defines species as a lineage of ancestor-descent populations that maintains its identity
evolutionary species concept
species concept: defines species as an irreducible group of organisms distinct from others and w a parental pattern of ancestry and descent
phylogenetic species concept
3 deuterostomes
(other phyla are protostomes)
chordata, echinodermata, hemichordata
2 subdivisions of protostomes
ecdysozoa
lophotrochozoa
protostome: consists of phyla that shed their outer body surface (ecdysis)
ecdysozoa
protostome: consists of phyla w either a lophophore or a trochophore
lophotrochozoa
feeding structure in lophotrochozoa
lophophore
larval form in lophotrochozoa
trochophore
