b15//2 Flashcards
how can scientists date rocks
fossils are found in rocks so they can date when different organisms existed
how may fossils be formed
-from the hard parts of animals that do not decay easily
-from parts of organisms that have not decayed because some of the conditions are absent
-parts of the organism is replaced by other materials
why is the fossil record incomplete
many early life forms had soft bodies
traces left were to have likely been destroyed by geological activity
how can extinction occur
a new disease
a new competitor may evolve
single catastrophic event
what is another reason why dinosaurs may have died out
the extinction was a slower process due to sea ice melting and cooling the sea temperature by around 9 degrees which meant there was less plankton to eat
what can some pathogens do, particularly viruses
they can mutate resulting in a new form called a mutation
why can a mutated pathogen spread rapidly
people are not immune to it
no effective treatment
how do some bacteria resist anti biotics
mutations of bacteria produces new strains which are resistant to the anti biotic
the resistant bacteria survive and reproduce and a whole new population is formed
what is MRSA
a bacterium that has evolved through natural selection
how are we trying to slow down the rate of development of resistant strains
anti biotics should not be used for mild infections
the correct anti biotic must be prescribed
how do scientists classify organisms
they study the differences and similarities between organisms
what is the order of classification
kingdom
phylum
class
order
family
genus
species
what is a species
very similar organisms that can breed together to produce ferttile offspring
what are the three domains
archaea
bacteria
eukaryota
what is an archaea
primitive forms of bacteria that can live in extreme conditions
what are evolutionary trees
models that can be drawn to show the relationship between different groups of organisms
