Classification and Evolution Flashcards
What is classification?
The organisation of living things into groups based on similarities and differences
Why is classification important?
Makes it convenient, ensure all biologists use same names for organisms, efficient and clear communication
What are the 7 taxas, in order from broadest to most specific?
Kingdom
Phylum
Class
Order
Family
Genus
Species
How are the latin names written when classifying organisms?
Genus then species, in Latin
Italics or underlines
Genus capitalised, species not
Can be shortened (E. coli)
Can have same specific name but different genus
Homo sapiens, Lutra lutra, Ailurus fulgens
Who devised the binomial naming system within classification?
Carl Linnaeus
What were the disadvantages of not having the binomial naming system?
Descriptive, local names based on characteristics
Differed from one place to the next
Common names and appearances don’t show relationships
What are the characteristics of organisms within the prokaryote kingdom? Example?
No nucleus or other membrane bound organelles
Unicellular
Small ribosomes
No visible feeding mechanism
e.g Bacteria (E. coli)
What are the characteristics of organisms within the protoctista kingdom? Example?
Nucleus and other membrane bound organelles (Eukaryotic)
Unicellular
Some have chloroplasts
Some photosynthesise (autotrophic), others are heterotrophic, some are parasitic
Don’t belong to any other group
e.g Amoeba, algae
What are the characteristics of organisms within the fungi kingdom? Example?
Nucleus and other membrane bound organelles (eukaryotic)
Cell wall of chitin
Can be uni or multicellular
Saprophytic - absorb nutrients from decay
Most store food as glycogen
e.g yeast (unicellular), mold, fungi that form mushrooms
What are the characteristics of organisms within the plantae kingdom? Example?
Nucleus and other membrane bound organelles (eukaryotic)
Multicellular
Contain chlorophyll
Cellulose cell wall
Autotrophic
Store food as starch
e.g moss, ferns, plants with flowers
What are the characteristics of organisms within the animalia kingdom? Example?
Nucleus and other membrane bound organelles (eukaryotic)
Multicellular
Heterotrophic through ingestion
Food stored as glycogen
e.g Humans
What did Carl Woose introduce to develop the current classification system? Why?
What are the features of each domain?
Added in domains above kingdoms.
Three domains: Archaea, Bacteria and Eukarya
Bacteria: 70s ribosomes, RNA polymerase has 5 proteins, known as true bacteria
Archaea: 70s ribosomes, RNA polymerase contains between 8-10 proteins and is similar to eukaryotic ribosomes, known as ancient bacteria, can live in extreme environments
Eukarya: 80s ribosomes, RNA polymerase contains 12 proteins
What is phylogeny?
Study of evolutionary relationships between species by studying how closely they are related
What does a phylogenetic tree show?
Time where species started to evolve separately, branch point to show this, common ancestory at another branch point
See evlolutionary relationships, indicate how closely related organisms are.
What four observations did Darwin make?
Offspring were generally similar in appearance to their parent
No two individuals are identical
Organisms produce a lot of offspring
Populations tend to stay stable in size
What conclusions did Darwin make?
Organisms struggle to survive, better adapted individuals survive, reproduce and pass on characteristics, over time can give rise to new species
What were some reasons why Darwin’s theory wasn’t believed?
Religion in society
Insufficient evidence
Not very well known researchers
Couldn’t explain how reproduction passed on characteristics
Advantages and disadvantages of using fossil records are evidence for evolution?
More complex organisms in more recent rocks
Sequence found in matches up
HOWEVER
Many fossils have been destroyed by Earths movements
Soft bodied organisms decomposed before fossilising
What is Cytochrome C?
Protein used in respiration, found in all living organisms, chain of amino acids, no differences = closely related, greater number of differences shows further back ancestry, evolutionary relationships
How does comparison of DNA help with classification?
More similar the sequence, the more closely related the species
How can biological molecules be used for classification?
Very different versions of same molecules are less closely related, evolved separately for longer
What is intraspecific variation?
Variation within a species
What is interspecific variation?
Variation between species
What are the two causes of variation?
Genes and evironment
How can meiosis and sexual reproduction lead to variation
Alleles: can inherit different combinations
Mutations: changes in DNA, in in somatic cell only changes individual, if in gametes can be inherited
Meiosis: independent assortment, crossing over
Sexual reproduction: no two gametes the same so not identical to each other, only half from each parent so not identical to either parent
Examples of environmental variation
Plants: light intensity, water content of soil, mineral concentration in soil, wind exposure to wind, height
Animals: flamingo turn pink on shrimp diet
How can environment lead to variation in phenotype?
Having a genotype that us not expressed due to interaction with the environment
What is the phenotype?
An individual’s observable traits, such as height, eye colour and blood type
What is the genotype?
All of the alleles that an organism carries on its chromosomes
What is continuous data?
Regulated by more than one gene, and is influenced by the environment. This type of variation is usually presented as a line graph or histogram
What is discontinuous data?
Regulated by a single gene, not influenced by any environmental factors. Presented on a bar or pie chart
Describe and explain the shape of a normal distribution graph
Forms a bell shaped curve
Normal distribution curve
Mean, mode, median at same point
50% of values below the mean, 50% above
Most values close to mean
Number of individuals at extremes are low
Spread of data can be determined using standard deviation
What is variation?
Differences between individuals
What is genetic variation?
Variation caused by possessing a different combination of alleles
What is environmental variation?
Variation caused by response to environmental factors
What is an adaptation?
A variation in a characteristic that increases an organisms chance of survival and reproduction
What are the three types of adaptation? What do they involve?
Anatomical: physical features (internal and external)
Behavioural: the way an organism acts (learned or inherited)
Physiological: processes talking place inside an organism (biochemistry)
Give an two examples of behavioural adaptations, one for both plants and animals
Plant: plants that flower at night to be pollinated by night time insects
Animal: grooming
Give an two examples of anatomical adaptations, one for both plants and animals
Plant: tree roots longer when water table lower
Animal: Darwins finches - different shaped beaks
Give an two examples of physiological adaptations, one for both plants and animals
Plants: plants that use C4 photosynthesis which avoids photorespiration and conserves water by enabling stomata to be closed
Animal: fewer sweat glands in desert animals
How is Marram grass adapted to its enironment?
Leaf rolled longitudinally, air trapped inside, becomes humid, reduces water loss. Can coil more tightly in very dry conditions
Thick waxy cuticle on outer side of leaf, reduces evaporation
Stomata protected by enclosed air space as on inner side of rolled leaf
Spongy mesophyll is very dense, few air spaces, less surface area for evaporation of water
Stomata in pits on lower epidermis, folded and covered in hairs, helps recude air movement and loss of water vapour
What are analogous structures?
Adaptations that perform the same function but have a different genetic origin
What are homologous structures?
Appear different but have same underlying structure, in different species, likely evolved from a common ancestor
What is the mechanism for natural selection?
Genetic variation exists between individuals in a population.
Some individuals will be more likely to survive (e.g. by being better at fighting disease) than others.
Individuals that are better at surviving than others have a selective advantage
Individuals with a selective advantage are more likely to survive to reproduce than others.
This means that the genes of an individual with a selective advantage are more likely to be passed onto offspring than the genes of an individual without a selective advantage
Individuals with a selective advantage are more likely to pass on their beneficial alleles than other individuals.
The next generation is more likely to have alleles that provide a selective advantage than alleles that do not.
This generation is also more likely to survive to reproduce and pass on their genes.
This causes the alleles that provide a selective advantage to increase in frequency in the population.
