B15: Theory of Evolution Flashcards
how did theory of evolution arise?
Charles Darwin
- supported by experimentation /knowledge of geology /fossils he discovered on round the world expedition
why was there controversy against charles darwin’s ideas?
- contridicted idea that God was creator of all species on earth
- not enough evidence
- mechanism of inheritance/variation werent known then
what did Jean- Baptiste Larmack think?
- changes that occured in a lifetime were passed onto offspiring
- if an induvidual repeated an action, the characteristic that allowed it to do so would be passed on
what did Alfred Wallace do ?
- developed theary of speciation
- had idea that those who didnt have characteristics for survival will die out
- joint studies with Darwin
process of speciation?
- variation due to mutations
- alleles that give an advantage for survival are selected for in natural selection
- populations of species can be isolated (by physical barriers) preventing them from breeding tgt
- different allelles can be advantageous in new environment , meaning these are passed
- over time the selection of different alleles causes genetic variation between 2 populations (no l;onger can be breed tgt to produce fertile offspring)
what did Gregor Mendel do?
- carried out breeding experiments on pea plants
- used smooth, wrinkled, green and yellow peas / observed offspring to see charactertics they inherited
- he concluded that : - offspring have some characterstics that their parents have bc they inherit hereditary units
- one unit is recieved from each parent
- units can be dominant/recessive ,not mixed tgt
why was mendel not recognised when he was alive?
genes/chromosomes were not yet discovered
how are fossils formed?
- parts of organisms have not decayed as O2 /MOISTURE were not present , so microbes that cuase decay could not survive
- parts of organism (teeth,bones) are replaced by minerals as they decay , forming rock structure of original part
- preserved traces like footprints remian due to ground hardening around it /forming a cast
what can fossils reveal?
- how anatomy of organisms have changed
- compare how closley related organisms are
why cant fossils tell us how life started on earth?
- most early life forms were soft bodied so decayed completely
- any fossils left have been destroyed due to geolgical activity
causes of extinction?
- changes in environment which they cant adapt to
- new predators
- new disease, which the species has no resistant alleles to
- compete for food with another species which has advantageous mutations
- catastrophic event
- destroyed habitat
how did antibiotic resistant bacteria arise?
- bacteria reproduce fast, so mutations occur –> result in new genes for antibiotic resistance
- those with antibiotic resistant genes survive / reproduce , passing advantageous gene
- population with this gene increases
what is mrsa ?
superbug that is resistant to mnay different antibiotics
how to slow development of resistant bacteria ?
- antibiotics shouldn’t be given for non serious/viral infections
- specific antibiotics should be given for specific bacteria
- patient should complete course of antibiotics or some bacteria will survive/mutate to become resistant
- antibiotics need to be used less in agriculture
what is the linnaean system?
Carl linnaeus put this forward in 1700s
- living things divided into kingdoms, phylum, class, order, family, genus, species
