Module 4.2.2 Classification & Evolution Flashcards
What is biological classification
The organisation of living & extinct organisms into systematic groups based similarities and differences between species
What is taxonomy
The study and practice of naming and classifying species & groups of species within the hierarchical classification scheme
What does D,K,P,C,O,F,G,S stand for
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
What is the binomial naming system
A system of naming species in which each species has 2 names: a generic name & specific description
What are the 5 kingdoms
Animalia
Plantae
Fungli
Protoctista
Prokaryotae
What are the 3 domains
Archaea, eukarya, bacteria
What are the features of the eukarya domain
protoctista, fungi, plantae & animalia
What are the features of the bacteria domain
different cell membrane
flagella with different internal structure
different enzymes (rna polymerase)
no proteins bound to their genetic material
smaller ribosomes than eukaryotes
different mechanism for dna replication
what are the features of the archaea domain
similiar enzymes for synthesising dna (RNA polymerase)
similiar mechanisms for DNA replication
smaller ribosomes than eukaryotes
production of some proteins that bind to their dna
what is homology
the existence of shared features that are inherited from a common ancestor. The shared features may not be used for the same function
what is phylogeny
the study of evolutionary relationships between organisms
what are the advantages of phylogeny
can be done without referring to Linnaean classification
produces a continuous tree whereas classification requires taxonomical groups
not as misleading
Linnaean doesn’t illustrate levels of diversity
What is the biological species concept?
The ability of 2 individuals to successfully produce viable, fertile offspring
What is the morphological species concept?
Whether individuals look similiar
What is the phylogenetic species concept?
How closely related individuals are evolutionary
What is the ecological species concept?
Whether the individual use/can use the same set of biological resources (whether or not they can occupy the same niche)
What were Darwin’s 4 main observations for his theory of evolution?
A) offspring genetically appear similiar to their parents (inheritance)
B) no 2 individuals were identical (genetic variation)
C) organisms have the ability to produce large amounts of offspring (competition & struggle for survival)
D) populations in nature tend to remain fairly stable in size (natural selection)
What were Wallace’s observations to contribute to the theory of evolution?
A) some organisms had advantageous adaptations evolved by natural selection
B) geographical boundaries often marked species boundaries
C) most of the individuals found in a habitat were best fitted for that environment
What are the 3 sources of evidence for evolution?
A) fossils
B) comparative anatomy
C) comparative biochemistry
What is a fossil?
The mineralised/preserved remains of an animal/plant or microorganism. Fossils may also consist of other traces of organisms e.g. footprints/burrows/faeces
How does a fossil form?
1) the animal/plant dies
2) organism becomes buried under sediment
3) high temperature & pressure turns sediment into stone
4) the remains dissolve & leave behind an empty space
5) minerals crystallise in the space & forms a cast (fossil)
What are some advantages of using fossils as evidence for evolution?
Fossils of simple organisms (bacteria/algae) are found in the oldest rocks whereas fossils of more complex organisms are found in younger rocks - shows simple life forms have gradually evolved over a very long time to more complex organisms
The sequence in which organisms are found matches their ecological links to each other (plants came before animals)
Scientists can show how closely related organisms have evolved from the same ancestor
Fossils allow relationships between extinct & living organisms to be investigated
What is the main issue of using fossils?
The fossil record isnt complete
What is a homologous structure?
A structure that appears superficially different (& may perform different functions) in different organisms, but have the same underlying structure
What do homologous structures provide evidence of?
They show divergent evolution due to migration/loss of habitat & convergent evolution (when organisms evolve the same characteristics but aren’t related at all e.g. flight)
What is comparative biochemistry?
The study of similarities & differences in the proteins & other molecules that control life processes
How does comparative biochemistry provide evidence for evolution?
Some important molecules remain highly conserved among species - slight changes that occur in these molecules can help identify evolutionary links
How is molecular evidence in the form of DNA used as evidence for evolution?
Mutations in DNA cause differences in its sequence as the genetic code is universal the same part of DNA codes for the same sequence of amino acids in animals, plants & bacteria
The more similar the sequence of DNA, the more closely related the species
The more differences in the DNA sequence, the earlier the evolution - less closely related
What is variation?
The differences between & within species
What is intraspecific variation?
Variation between members of the same species
What is intraspecific variation used for?
Used to study natural selection & evolution
What is interspecific variation?
Differences between species
What is interspecifc variation used for?
Used to identify different species & to classify them
What is continuous variation?
Variation in a feature that shows a range of phenotypes between 2 extremes with many intermediates e.g. leaf length, body mass, height
What is the basis about continuous variation?
AKA quantitative variation
There are no distinct categories
Characteristics are not controlled by a single gene but polygenes, these features are polygenic e.g. height
Usually presented in a histogram
What is discontinuous variation?
Variation in a feature that has distinct categories without any intermediates e.g. human blood groups
What is the basis of discontinuous variation?
AKA qualitative/discrete variation
There are distinct categories
Characteristics area usually controlled by a single gene & the environment usually has no effect on the phenotype
Can be presented as a bar/pie chart
What are the 2 causes of variation?
Genetic
Environment
What are the different causes of genetic variation?
Alleles
Mutations
Meiosis
Sexual reproduction
Chance
What are alleles & how do they cause genetic variation?
Different versions of a gene - the individuals in a species population may inherit different alleles of a gene
What are mutations & how do they cause genetic variation?
Changes to the DNA sequence - genes can lead to changes in the protein thats coded so it can affect the physical & metabolic characteristics
What is meiosis and how can it cause genetic variation?
The formation of gametes - the process of independent assortment & crossing over to ‘mix up’ the genetic material
How does sexual reproduction cause genetic variation?
Offspring inherit one set of chromosomes from each parent - linked to meiosis
How does chance increase genetic variation?
Random fertilisation as a result of which gametes combine
What can cause environmental variation?
Climate, food, lifestyle
