Evolution Flashcards
when does evolution occur?
when heritable characteristics of a species change
what is evolution?
- cumulative change in heritable characteristics of a species over time
- or a change in allele frequency of a gene
what is some strong evidence for evolution
- fossil records (strange organisms that don’t live now + “missing links”)
- selective breeding of domesticated animals showing natural selection
- homologous structures (limbs + bones)
- vestigial structures (appendix)
- comparative embryology
- industrial melanism (moths going black)
- geographical distribution of organisms
what does evolution of homologous structures by adaptive radiation suggest? and what is adaptive radiation
- adaptive radiation is many species from one origin
- similarities in structure when there are differences in function (basically lots of common ancestors)
how does continuous variation across geographical range match the concept of gradual difference?
- species variation across regions
- don’t see all variations within given region at same time
- goes against “all species created at once”
describe industrial melanism in relation to melanistic insects in polluted areas
- pale lichen covering trees was killed due to sulphur dioxide pollution
- soot from coal blackened tree branches
- melanic moths could camouflage into pollution, therefore surviving more than whiter moths
compare the pentadactyl limbs of mammals, birds, amphibians and reptiles with reference to motion
- crocodiles walk of crawl on land using hind limbs
- penguins use hind limbs
- echidnas use all four limbs for walking
- frogs all four limbs for walking and back legs
who is Charles Darwin and what did he do
- went on HMS Beagle in 1831 to Galapagos
- collected samples and noticed differences in birds based on location
- published book on origin of species by natural selection
when can natural selection occur?
when there is variation amongst members of the same species
what causes this variation?
mutation, meiosis, and sexual reproduction
what are adaptations
characteristics that make individuals better suited for the environment
how does reproduction encourage natural selection (3 ways)
- species produce more offspring than environment can support
- better adapted individuals produce more offspring
- characteristics passed on to offspring
what does natural selection increase and decrease?
- increase: frequency of characteristics that make individuals better adapted
- decrease: frequency of other characteristics leading to changes within the species
explain evolution of antibiotic resistance
- bacteria will become resistant to new antibiotic within years due to rapid mutation/reproduction (they reproduce FAST)
- survivors become more common in gene pool
- can pass resistance through reproduction (plasmid transfer)
- treating livestock with antibiotics contributes to issue
outline natural selection (with vocab)
- can only occur if there is variation amongst the gene pool
- individuals with traits better suited to environment tend to survive and thus reproduce
- this causes changes in allele frequency of genes over time
- increases frequency of individuals adapted to environment
- although, this allele frequency can go back and forth
