Classification and evolution✅ Flashcards
define classification and species
classification: the sorting of organisms into groups
species: a group of organisms that can interbreed to produce fertile offspring
what are the advantages of classification systems
analyse evolutionary relationships between organisms
predict characteristics (as species grouped together are likely to share characteristics) and identify species
share research findings (without confusion or ambiguity)
what are the 5 kingdoms
Prokaryotae, Protoctista, fungi, plantae, animalia
describe the prokaryotae kingdom
uni or multicellular, domain(s), organelles present, cell wall, how do they gain nutrients
unicellular
bacteria and archaea domains
no organelles
yes (peptidogylcan/murein) cell wall
autotrophic or heterotrophic
describe the protocista kingdom
uni or multicellular, domain(s), organelles present, cell wall, how do they gain nutrients
unicellular or multicellular
eukarya domain
yes organelles
no cell wall
autotrophic or heterotrophic
describe the fungi kingdom
uni or multicellular, domain(s), organelles present, cell wall, how do they gain nutrients
unicellular or multicellular
eukarya domain
yes organelles
yes (chitin) cell wall
saprotrophic (extracellular digestion)
describe the plantae kingdom
uni or multicellular, domain(s), organelles present, cell wall, how do they gain nutrients
multicellular
eukarya domain
yes organelles
yes (cellulose) cell wall
autotrophic
describe the animalia kingdom
uni or multicellular, domain(s), organelles present, cell wall, how do they gain nutrients
multicellular
eukarya domain
yes organelles
no cell wall
heterotrophic
what are 3 domain system
bacteria, archaea, eukarya
what is added to the 5 kingdom system to become the 6 kingdom system
archaebacteria
why have domains been introduced
Woese domain classification based on several molecular observations, which include;
bacteria cell walls contain peptidoglycan but those of archaea do not
the RNA polymerase of Archaea contains 8-10 subunits, but bacterial RNA polymerase contains only 5 subunits
archaea have rRNA that is different to the rRNA of bacteria and eukarya
what is phylogeny
the study of evolutionary relationships between organisms
explain why the structure of a phylogenetic tree may change over time (2 marks)
new evidence (such as comparative genetics)
the evolutionary relationships between species are re-evaluated
suggest what advantages phylogenetic classification has over traditional hierarchical taxonomic classification (3 marks)
evolutionary positions can be compared/ evolutionary histories can be mapped
phylogenetic trees avoid arbitrary groupings of species
the use of genetic and evolutionary comparisons enable more precise classification
state 2 differences between bacteria and fungi (2 marks)
bacteria have peptidoglycan in their cell walls/fungi have chitin in their cell walls
bacteria are always unicellular, whereas some fungi are multicellular
bacteria lack organelles
fungi can feed using saprotrophic nutrition
fungi have hyphae
explain why classification systems have changed over time, using the introduction of domains as an example (4 marks)
new evidence shows different relationships
example of new evidence (eg DNA sequencing)
2 examples of the evidence used in domain classification (eg RNA polymerase, cell wall structure, rRNA)
what is the three types of evidence for evolution
palaeontology (fossils)
comparative anatomy
comparative biochemistry
what evidence does palaeontology (fossils) show for evolution
fossils of simple organisms tend to be found in the oldest rocks, whereas more complex organisms are found in more recent rocks
plant fossils appear in older rocks, before animals which matches their ecological relationship
similarities between different fossil species reveal gradual anatomical change
how does comparative anatomy show evidence for evolution
homologous structures (anatomical features that have slight differences but same underlying structure) provide evidence of divergent evolution
the embryos of related species have similar appearances, despite considerable interspecific differences between adults. This indicates that different species have evolved from a common origin
how does comparative biochemistry show evidence for evolution
the rate of mutations in DNA can be calculated. This enables evolutionary relationships to be analysed. The closer the relationship between 2 species, the fewer the differences in their DNA sequences
what was Charles Darwin influenced by
Charles Lyell’s geological theories: fossils are evidence of animals living millions of years ago and natural process can result from gradual changes and accumulations
His observations on Galapagos Islands (slight difference in beaks and claws) between species on neighbouring islands developed adaptations
his studies on artificial selection by pigeon breeders enabled him to draw parallels with how natural selection might work
what can the DNA base sequence of 2 species tell us about their evolutionary relationship (2 marks)
the greater the similarities in the base sequences
the closer the evolutionary relationship
suggest why the fossil record fails to provide complete picture of evolutionary history (3 marks)
gaps/missing links in the record
some species do not fossilise
some fossils have been destroyed since formation
Explain how the parallels between artificial selection and natural selection that Darwin observed (3 marks)
variation exists (between individuals within population)
both artificial selection and natural selection involves individuals with favoured traits breeding
in both cases the favoured traits are inherited by offspring
over many generations alleles frequencies change within the populations