Classification and evolution Flashcards
define classification
process of naming and organising organisms into groups based on their characteristics
name the eight groups in the classification hierarchy
domain - kingdom - phylum - class - order - genus - species
what are the two components in the binomial name system
generic name - capital letter, two closely related species
species name - lowercase letter, species the organism belongs to
what’s an advantage of the binomial naming system?
it is universal
name the 5 kingdoms and 3 domains
prokaryote, protoctista, fungi, plantae, animalia
bacteria,archaea, eukaryota
define taxonomy
study of classification
define species
. if they can successfully mate with each other
. tend to have similar:
physical appearance, anatomy, genetics,phylogeny and physiology
give some features of prokaryotes
no nucleus
loop of dna + naked
no membrane bound organelles
small ribosomes
give some features of protoctista
eukaryotic
autotrophic/heterotrophic
show plant/animal-like features
give some features of fungi
eukaryotic
walls made of chitin
saprophytic
give some features of plantae
eukaryotes
multicellular
cellulose cell wall
autotrophic
chlorophyll
give some features of animalia
eukaryotes
multicellular
heterotrophic
how was the domain system created
analysing molecular differences between organisms to determine their phylogeny
how are organisms classified in a kingdom
based on similar characteristics
how has biological molecules been used as evidence of the three domains
cytochrome C - if sequences are the same, two species must be closely related
DNA - the more similar the sequence part of the DNA the more closely related
what is it meant by convergent evolution
when two unrelated species adapt in similar ways so look similar
explain how natural selection results in evolution
. Species with beneficial alleles are more likely to survive, reproduce and pass on their alleles to the next generation.
.Members of the next generation with beneficial alleles are then also more likely to survive, so the frequency of the beneficial alleles within the population increases.
what does directional selection mean and give an example
the alleles of an extreme type are selected for e.g antibiotic resistance bacteria
explain how bacteria become resistant to antibiotics
A few bacteria have resistance.
A selection pressure is applied
The resistance alleles are selected for.
Bacteria evolve to become resistant
what is stabilizing selection and give an example
the alleles of the mean / middle range are selected for.
This happens when the environment is stable, and the genetic diversity in a population decreases.
For example, human birth weight undergoes stabilising selection.
explain how stabilising selection work
Human birth weight can vary.
A normal birth weight is beneficial.
Natural selection keeps birth weights in the middle range.
explain anatomical adaptations
physical features of an organism that help them to survive such as the long neck of giraffe which helps it to reach leaves growing on tall trees.
explain physiological adaptations
internal body functions that help an organism to survive e.g warm-blooded organisms
explain behavioural adaptations
things that an organism does to survive, such as birds migrating to the south in the winter because there is more food there.
what are other evidence for natural selection
fossils , genomic DNA and molecular evidence
what causes variation
genetic and environmental
differentiate between intraspecific and interspecific variation
variation within same species
variation between different species
differentiate between continuous and discontinuous variation
C: variation exists as gradual changes over a range e.g. height, root length
D: variation exists as distinct categories e.g. blood group, bacteria shape
what are the three types of adaptations
anatomical,physiological and behavioral
give an example of organisms from different taxonomic groups with similar features
marsupial and placental moles live in different continents but share similar anatomical features because they are adapted to similar environments
give some implications of evolution for humans
bacterial antibiotic resistance means infections are harder to treat
pesticide resistance means entire crops could be destroyed
