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4.5 species and taxonomy - Coggle Diagram
4.5 species and taxonomy
lesson 1: species, courtship behaviour & phylogeny
species
a group of organisms that can interbreed successfully to produce fertile offspring
courtship behaviour
e.g calls/song, displays, dancing
has four main purposes
idenitify and attract members of your own species
identify and attract a mate that is fertile and receptive to mating
establish a pair bond that will lead to raising of offspring
synchronise mating
taxonomy (biological classification)
organising species into groups (taxa) that are:
hierarchical (each large group has smaller groups within it)
non overlapping
linnaean classification system
domain
kingdom
phylum
class
order
family
genus
species
phylogenetic classification/phylogeny
arranging species into taxa according to their evolutionary relationships and origin
this means
they are placed in groups with organisms they are most closely related to
these will be organisms that all evolved from a common ancestor
lesson 2: phylogeny and binomials
phylogenetic classification
evolutionary relationships are (how closely related species are) determined by measuring similarities and differences in:
physical characteristics
DNA base sequences
mRNA sequencing
amino acid sequences
shapes of self antigens/antibodies
convergent evolution
the process where unrelated organisms independently evolve similar traits due to adapting to similar environmental pressures
the organisms have similar alleles as well as advantageous characteristics
why is it useful to group organisms in this way
Scientists can communicate clearly about different species
Knowledge that relates to one species can often be partially applied to other, closely related species, e.g. if one species in a taxon has medicinal properties then it is likely that other species will too
It allows scientists to gain an accurate count of the number of species, which is useful for conservation purposes
binomial naming system
each species binomial name consists firstly of the name of their genus and secondly the name of their species
e.g a lions binomial name is Panthera leo
rules
Genus has a capitol letter and species has a lowercase letter
if typed the name should be in italics
if handwritten the name should be underlined
3 domains (highest taxonomic rank)
eukarya
multicellular organisms that contain membrane bound organelles and 80s ribisomes, linear DNA associated with histone proteins
bacteria
no membrane bound organelles, 70s ribisomes, murein cell walls, circular DNA not protein associated
archaea
no murein in cell walls, more complex form of RNA polymerase, genes and protein synthesis much similar to eukaryotes
lesson 3: how have evolutionary relationships been clarified
genome sequencing
3 types of data used
DNA
mRNA
amino acids (of a protein)
Scientists will choose specific proteins or sections of the genome for comparison between organisms
Looking at multiple proteins or multiple regions of the genome will allow for a more accurate estimate of evolutionary relatedness
For all types of sequence data it can be said that the more similar the sequences, the more closely related the species are
Two groups of organisms with very similar sequences will have separated into separate species more recently than two groups with less similarity in their sequences
Species that have been separated for longer have had a greater amount of time to accumulate mutations and changes to their DNA,mRNA and amino acid sequences
immunology
proteins of an organism can also be compared using immunological techniques
The protein albumin is commonly used for these experiments
method
Pure albumin samples are extracted from blood samples taken from multiple species
Each pure albumin sample is injected into a different rabbit
Each rabbit produces antibodies for that specific type of albumen
The different antibodies are extracted from the different rabbits and are then mixed with the different albumin samples
The precipitate (antibody-antigen complexes) resulting from each mixed sample is weighed
results
The greater the weight of the precipitate, the greater the degree of complementarity between the antibody and albumin
