Classification And Evolution Flashcards
What is classification
Putting things into groups
What is taxonomy
Is the science of systematic classification
- classes organisms in taxa
What are the 8 taxas
-domain
-kingdom
-phylum
-class
-order
-family
-genus
-species
What is phylogeny
The study of evolutionary relationships
Phylogenetic classification
Reflects evolutionary relationships
-more closely related 2 organisms are the more and smaller taxa they share
What are the 5 kingdoms
Prokaryota, protoctista, fungi, plant and animal
What is the Scientific naming of a species
-Binomial name (which includes:)
Genus name (capital letters)
Unique species name (lowercase)
What are the 2 rues for handwriting and typing species name
In handwriting- must be underlined
In typing- must be in italics
How were kingdoms found
-better microscopes
-biochemistry
Who was the 3 domain system proposed by and what is it for
Carl woese
- classifies organisms on the basis of differences in there rRNA
-allows to see differences between any 2 organisms
What are the 3 domains
-archae
-bacteria
-eucarya
What are the reasons behind the 3 domain system
-bacteria and archaea are fundamentally different
-archaea is more similar to eukaryotes than bacteria
- they have different cell membranes and flagella structures and different enzymes for synthesising RNA
What is the problem with classifying organisms by characteristics
Convergent evolution
- 2 unrelated species could adapt to the same environment so look similar
What is cytochrome C and what is it for
Haem protein found in mitochondria
- is small sequence of amino acids
- if sequence is similar 2 organisms are closely related
- the more differences found the less closely related
An example of amino acid sequence found in cytochrome c
It is identical for humans and chimpanzees (so more closely related together)
What is DNA and what is it for
-Found in all living organisms
-Provides genetic code
-The more similar the sequence the more closely related the species
What is variation
Differences that occur within same species and between different species
What are the 2 types of variation
Interspecific- between species
Intraspecific- within same species
What are the 2 causes of variation within a species
Genetic variation- caused by differences between individual genes (can be passed onto offspring)
Environmental variation- brought by the influence of the environment on the way they grow and develop (cannot be inherited)
*evolution only concerned with genetic variation.
What are the sources of genetic variation
Independent assortment!
-random fertilisation gives new combinations of alleles
Mutations:
-may create new alleles
-is heritable
-mutations in gamete forming cells are passed onto offspring
What is continuous variation
Individuals showing gradual change from one to another with no distinct types
How is continuous variation done
-It’s polygenic
-By the interaction of many different genes
-Huge number of different allele combinations
What is discontinuous variation
When individuals are clearly divided into distinct types with no overlapping or merging
How is discontinuous variation done
-Small number of different alleles combinations
-Affected by one of few genes
What is adaptation
Any variation that helps an organism survive
What are the 3 different types of adaptations
-anatomical- structure of organisms
-behavioural- behaviour enhancing survival
-physiological- biochemistry- function of cell processes
Give anatomical adaptations of marram grass
~long roots- plant can reach underground
~leaves are curled- reduces SA exposed to wind so moisture can build up inside
~waxy cuticle- reduces evaporation of water
~lower epidermis covered in hair- air movement reduced so water stays inside
Give behavioural adaptations of marram grass
~When covered by sand it grows more quickly to reach sunlight
~responds to water shortage by rolling leaf more tightly
Physiological adaptations of marram grass
~ has many lignified cells to provide support when water is not available
~ can survive in salty conditions so maintains cell water potential lower than other plants
Behavioural adaptation of earthworm
Quickly contracts when touched and goes back into burrow-
has no eyes
What are Darwin’s observations
- all living organisms over produce
-organism within a species vary - some of these variations are inherited
Overproduction
Environmental factors can keep numbers down these may be biotic or abiotic
What is biotic factors and give examples
Living organisms
E,g - predators, prey animals
What is abiotic factors and give examples
Non living factors
E.g sunlight, water, grass
What is selection pressure
Evolutionary force that causes a particular organism to be more favourable in certain environmental conditions
E.g of selection pressure
Predation of foxes
-increases chance of variation being passed onto offspring and decreases chance of others
-this is natural selection
-organisms with best adapted characteristics will pass it down
How does natural selection occur
- mutation in allele
-causes intraspecific variation
-when resources are scarce in environment selection pressure occurs
-advantageous individuals survive
-they pass on these characteristics and next generation has successful traits
What is a species
Group of organisms that can interbreed producing fertile offspring
What is Speciation
Formation of a new species
What is needed for speciation to occur
Populations must be isolated from each other
What is Allopatric speciation
Population becomes separated form the rest by a geographical or physical barrier
What does differing selection pressure do to separate populations
Makes them genetically different so can’t breed with each other again
What is sympatric speciation
When populations become separate by reproductive barriers
Give 2 evidence for evolution
-fossils
~ shows old species and new risen ones
-biological molecules
~2 closely related species will have similar bio molecules and would’ve separated only recently
