Biological Evolution Flashcards
define biological evolution
DESCENT WITH MODIFICATION through the mechanism of NATURAL SELECTION
define microevolution
small-scale evolutionary change within the species level, caused by changes in allele or genotype frequencies that occur within a population of a particular species over a few generations
define macroevolution
large-scale evolutionary events over geological times, resulting in phenotypic changes in populations that create at least a new species
involves descent of different species from shared ancestors over many generations
state the two essential features of Lamarck’s theory of evolution
use and disuse of organs
inheritance of acquired characters
what does “use and disuse of organs” mean?
when an organism developed a need for a particular structure, its development was induced
what does “inheritance of acquired characters” mean?
beneficial characteristics could be inherited
(false)
state the seven essential features of darwin-wallace’s theory
- organisms have great potential to reproduce
- environmental restrictions / constancy in numbers
- struggle for existence / survival
- variation within a population
- survival of the fittest by Natural Selection
- differential reproduction (like produces like)
- formation of new species
define natural selection
process by which the environment selects for fit individuals with inherited traits that are best suited to the local environment. individuals with selective advantage are more likely to survive and reproduce, producing more offspring
define natural selection
process by which the environment selects for fit individuals with inherited traits that are best suited to the local environment. individuals with selective advantage are more likely to survive and reproduce, producing more offspring
what are the two essential features of darwin-wallace’s that explain the tendency to reproduce more than can survive?
organisms have great potential to reproduce + constancy in numbers / environmental restrictions
what is fitness in evolution?
relative reproductive success of individuals within a population in leaving offspring in the next generation
OR
relative success of a genotype compared to others
define adaptation
an evolutionary modification that improves the chances of survival and reproductive success in a given environment
what is the main difference between darwinism and neo-darwinism?
neo-darwinism includes principles of Mendelian genetics and knowledge of molecular biology (eg. mutations and allele frequency changes)
what are the different essential features of neo-darwinism compared to darwinism?
- variation within a population
- survival of the fittest by Natural selection
- differential reproduction (like produces like)
- formation of new species
what does neo-darwinism include about variation within a population that darwinism did not?
variations are a result of spontaneous mutations, not due to individual needs
variation is controlled by genes
what does neo-darwinism include about natural selection that darwinism did not?
individuals with genetic variations best adapted to the environment have a selective advantage
what does neo-darwinism include about differential reproduction that darwinism did not?
proportion of fit individuals with favourable genes and a selective advantage increases with each generation
what does neo-darwinism include about formation of a new species that darwinism did not?
speciation is due to natural selection AND separation of population (no interbreeding)
define anatomical homology / homologous structures
structural / anatomical similarities in homologous structures, which suggest they descended from a common ancestor with that feature
similarity in characteristics resulting from a shared ancestry
give examples of anatomical homology
forelimb and hindlimb bones of vertebrates
forelimb descended from pentadactyl limb (5 fingers)– human arm, cat limb, whale flipper, bat wing
vestigial structures
early embryonic development: chicken and humans have pharyngeal pouches and post-anal tails
define divergent evolution
a common ancestor subject to different environments and selection pressures diversified into different species
what is genetic isolation?
genetically compatible interbreeding natural populations that is genetically isolated from other such groups
how is the genetic species concept applied, and what are its limitations?
mitochondrial and nuclear genomes
common gene pool and karyotypes may change due to: directional selection and interbreeding btw 2 specieis
define the biological species concept
know this!
a species is a population whose members can interbreed in nature to produce Viable, Fertile Offspring (VFOs)