classification and evolution Flashcards
why do we classify species?
to identify new species, predict characteristics and find links between species
Describe the domains
3 Domains - Archaea, Bacteria, Eukaryote
Describe the 5/6 kingdoms
6- Archaebacteria, Eubacteria, Animalia, Plantae, fungi, Protoctista
5-Prokaryote, Animalia, Plantae, fungi, Protoctista
Describe what comes after the domains
Eukaryotes- 80s ribosomes RNA polymerase with 12 proteins
Archaea- 70s ribosome RNA polymerase with 8-10 proteins
Eubacteria- true bacteria with peptidoglycan in cell wall and always unicellular
what is an advantage of phylogenetic classification?
It’s based upon evolutionary relationships between organisms and their ancestors, classifying species into groups. It reveals how closely related organisms are.
Describe phylogenetic trees
indicates lines of descent and divergence over time. The oldest species is shown at the base (left) of the tree above, while the most recent species are shown at the ends of the branches of the tree (right).
what is used to determine phylogeny?
Molecular comparisons - Comparisons between DNA and amino acids in proteins e.g. cytochrome C.
Development studies - Comparisons of embryonic similarities and differences.
Anatomical examinations - Comparisons of similarities in species’ physical characteristics e.g. from fossils.
Behavioural analyses - Comparisons of similarities and differences between the behaviour of species.
what 3 things are used for evidence of evolution?
the fossil record
comparative anatomy
comparative biochemistry
what is evidence for evolution from the fossil record?
simple bacteria and algae found in the oldest rocks while newer more complex vertebrates at the top
allows us to compare extinct and alive species
what are limitations of the fossil record?
Many organisms decompose before they can fossilise.
Fossilisation is uncommon, and requires specific conditions for an organism to be preserved.
Over time, many fossils have been lost due to erosion or geological processes.
Many organisms have not yet been discovered.
Certain organisms, especially those with soft bodies, are less likely to fossilize, leading to gaps in the record.
what is evidence for evolution from comparative anatomy
Homologous structures are physical features in different species that have a similar underlying structure but may serve different functions.
Organisms who share homologous structures likely evolved from a common ancestor, and have adapted these structures for different functions.
Homologous structures are evidence for divergent evolution, where organisms evolve different adaptive traits as they occupy new ecological niches.
what is meant by homologous structure
structures that look similar but have different underlying structures.
what molecules do we look at under biochemistry evidence for evolution?
ytochrome c - This is a highly conserved protein involved in cellular respiration, so slight changes can help identify evolutionary links.
Ribosomal RNA - This molecule is integral to protein synthesis so it changes slowly, making it useful for showing connections between species that diverged long ago.
Nuclear, mitochondrial, or chloroplast DNA - Species that are more closely related will have more similar DNA sequences.
Messenger RNA - Base sequences of mRNA are complementary to DNA so can assess DNA diversity.
Amino acids - If they are closely related evolutionarily, two species have more similar amino acid sequences because they are determined by mRNA and DNA.
what is convergent evolution and analogous structures
similarities due to living in the same environment develop analogous structures which have the same function but different evolutionary origins
genetic factors that affect variation
Mutations - Changes to genes and chromosomes that may be passed on to the next generation.
Meiosis - New combinations of alleles are present in the gametes formed, produced by independent assortment of chromosomes and crossing over between chromatids.
Random fertilization - Random fertilization of gametes produces new combinations of alleles in a zygote.
What are environmental factors that affect variation
Light
nutrient and food availability
Temperature
Rainfall
Soil conditions
pH
