Classification & Evolution Flashcards
what is classification
devising a specific grouping process and assigning different organisms to groups
why is it essential to use molecules (DNA or cytochrome c) as evidence
no identical in all species so when comparing sequences of amino acids in samples, similarities and differences can be identified to classify
phylogeny
the study of the evolutionary relationships between species which involves studying how closely related different species are
the more recent the common ancestor…
the more closely related the 2 species
taxonomy
the study of the organisation of organisms (taxa) into hierarchies, which attempt to take into account their supposed evolutionary descent
taxon
a group of organisms that share common features
species
a group of individuals with a large number of features in common, can interbreed and produce fertile offspring
why is Latin not English
it is a universal scientific language
common ancestor
the most recent individual from which a set of organisms in 2 or more different groups are directly descended
natural selection
a process of evolution by selecting individuals with certain adaptations to survive and reproduce, which are passed on to the next generation, over time more and more individuals will have the adaptive characteristics so has been ‘selected’
development of identical twins
start as 1 cell that divides and separates into 2 cells which form 2 separate people- 2 original cells have same genetic information but DNA replication /cell division introduces changes to DNA. also environ. difference in womb/after birth
intraspecific variation
variation within species- different characteristics between diff people
greater the genetic diversity of a species, greater the intraspecific variation
interspecific variation
variation between species- characteristics used to separate members of 1 species from another
continuous variation
there are 2 extremes and a full range of intermediate values between them, often regulated by more than one gene and influenced by environ (e.g. height)
discontinuous variation
2 or more extinct value categories with no intermediate values, members of species may be evenly distributed between diff forms/more of one type, regulated by single gene and not influenced by environ. (e.g. gender)
inherited/genetic variation
unique combination of alleles inherited from our parents defines our characteristics, we share alleles with other members of our species/other species but never complete match
environmental variation
characteristics are affected by the environment e.g. skin will tan/go darker with exposure to sunlight
combined effects as a cause of variation
environmental and genetic variation are not isolated, not all our genes are active at any 1 time and changes in the environ. can also directly affect which genes are active e.g. humans now taller due to better diet but also depend on genes
role of adaptations
help the organism to cope with environmental stresses and obtain the things they need to survive
a well-adapted organism will be able to….
find enough food/water/photosynthesise well, get enough nutrients, defend from predators/diseases, survive physical conditions of its environ, respond to changes in environ, sufficient energy for successful reproduction
convergent evolution
when 2 unrelated species living in a similar habitat evolve similar adaptations e.g. marsupial and placental moles both have short fur
