Module 4- Classification and Evolution Flashcards
what were darwin’s 4 main observations?
-offspring appear similar to their parents
-no two individuals were identical
-organisms have the ability to produce large numbers of offspring
-populations in nature tend to remain fairly stable in size
what are fossils?
the remains or impressions of prehistoric plant/animals preserved in rocks
what is a homologous structure?
structure that appears superficially different in different organisms but has the same underlying structure
what is phylogeny?
based on the closeness of evolutionary relationships
what were early classification systems based on?
physical characteristics
what is classification?
grouping organisms into groups based on similarities and differences
what is the relationship between classification and phylogeny?
modern classification reflects phylogeny
what can be learnt from fossils?
fossils deeper in the ground are older than
those near the surface and show that organisms change over time
what is intraspecific variation + example?
within species e.g. human height and eye colour
what is interspecific variation + example?
between species e.g. mouse has 4 legs bird has 2 legs
what is the formula for a histogram?
frequency density=frequency/class width
what is natural selection?
process by which organisms best suited to their environment survive and reproduce passing on their characteristics to their offspring through their genes
how is genetic variation caused?
meiosis
what is the process of natural selection?
-variations exist within a population
-those with the characteristics best suited to the environment survive and reproduce
-genes for best characteristics are passed onto offspring
how does evolution in some species have implications for human populations? (antibiotics)
-MRSA has developed resistance to many antibiotics
-bacteria replicate rapidly which can cause mutations in genes resulting in alleles that provide resistance to antibiotics
-when exposed to antibiotic resistant bacteria survive and continue to reproduce passing on the allele for resistance to offspring
-non resistant don’t survive so resistant population increased