Classification And Evolution Flashcards
What are the 7 taxonomic groups in order?
Kingdom Phylum Class Order Family Genus Species
Who created the hierarchical classification system?
Carl Linnaeus
Why do scientists classify organisms?
To identify species
To predict characteristics
To find evolutionary links
What are the 3 domains?
Archaea
Bacteria
Eukarya
What is a species?
A group of organisms that can produce fertile offspring
What is binomial nomenclature?
All species are given a scientific name consisting of 2 parts. The genus and the species
What’s are the 5 kingdoms?
Prokaryotae Protoctista Fungi Plantae Animalia
Features of prokaryotae?
Unicellular
No nucleus or membrane bound organelles
No visible feeding mechanisms
General features of protoctista?
Mainly unicellular
A nucleus and membrane bound organelles
Some have chloroplasts
Nutrients acquired by photosynthesis
Some are sessile, others move by cilia or flagella.
Fungi general features?
Uni or multicellular
Have a nucleus and membrane bound organelles and a cell wall made of chitin
No chloroplasts or chlorophyll
No locomotion mechanism
Have a body or mycelium made from threads or hyphae
Nutrients acquired by absorption (saphrophytic)
Store food as glycogen
General features of plantae?
Multicellular
Have a nucleus, membrane bound organelles and cell wall made of cellulose
All contain chlorophyll
Most do not move
Nutrients acquired by photosynthesis
Store food as starch
Features of animalia?
Multicellular
Nucleus and membrane bound organelles
No chloroplasts
Move with aid of cilia, flagella or contractile proteins
Nutrients acquired by ingestion
Food stored as glycogen
How did Carl Woese’s system classify organisms?
Groups organisms using differences in sequences of nucleotides in the cells rRNA
What are archaebacteria?
Can live in extreme environments, these include thermal air vents, anaerobic conditions and highly acidic environments. Eg methanogens
What is phylogeny?
The name given to evolutionary relationships between organisms
What does phylogeny show?
It reveals which group a particular organisms is related to and how closely related the organisms are.
If branches are closer together on phylogenetic trees, what does this mean?
There is a closer evolutionary relationship
Where is the earliest species found on a phylogenetic tree?
At the base of the tree
What are 2 descendants from the same node called?
Sister groups
Advantages of Phylogenetic classification?
Can be done without reference to Linnaean classification.
Phylogeny produces a continuous tree whereas classification requires discrete taxonomic grouping.
The hierarchy nature of Linnaean classification can be misleading as it implies that different species within the same rank are equivalent.
What is the evidence for Evolution?
Palaeontology
Comparative anatomy
Comparative biochemistry
What is the fossil record?
Where different layers of rock correspond to different geological eras ( most recent on top). The fossils in each layer change over time abs this can prove how organisms have changed over time too
What evidence is provided by the fossil record?
Complex fossils found in more recent strata whereas simpler organisms fossils found further down = supports the evolutionary theory.
The sequence in which the organisms are found matches their ecological links to each other. Plant fossils appear before animal fossils, supporting the fact that animals require plants to survive.
Can show similarities in the anatomy of fossil organisms, can show evolution from a common ancestor
Fossils allow relationships between extinct abs living organisms to be investigated
Disadvantages of fossil record?
It’s not complete. Many organisms are soft bodies which means they decompose quickly before they have a chance to fossilise.
Conditions needed for fossilisation are not always present
Many fossils have been destroyed by natural disasters or have just not been discovered yet.
What is comparative anatomy?
The study is similarities and differences in the anatomy of different living species.
What is a homologous structure?
A structure that appears superficially different ( and may function differently ) in different organisms, but has the same underlying structure.
Name an example of a homologous structure?
Pentadactyl limb
What is comparative biochemistry?
The study of similarities abs differences in the proteins and other molecules that control life processes.
How can comparative biochemistry be used to explain evolution?
Molecular sequencing in the 2 organisms can be compared by looking at DNA bases and amino acid sequences.
The differences that exist are plotted against the rate where the animals undergo neutral base pair substitutions, then period of time where common ancestor shared can be pin pointed.
Why is ribosomal RNA often used as evidence for evolution?
Because it has a very slow rate of substitution.
What is inter specific variation?
Variation between members of different species.
What is intraspecific variation?
Variation between organisms within a species
What two factors cause variation?
An organism is genetic material
The environment in which an organism lives
Name some genetic causes of variation?
Alleles
Mutations
Meiosis and crossing over
Sexual reproduction
Chance
Give an example of an environmental causes variation in humans
Scar on the body from an accident or a disease
What is most variation caused by?
A combination of genetic factors and environmental factors
What is discontinuous variation?
The characteristic that can only result in certain values for example, gender
What is continuous variation?
The characteristic that can take any value was in a range e.g. height
What type of graph is continuous variation plotted on?
A normal distribution curve
Characteristics of a normal distribution curve?
The mean, mode and median are the same
The distribution has a bell shape which is symmetrical around the mean.
50% of values are less than the mean and 50% are greater than the mean
Most values like close to the mean value
What is a students t-test used for?
It’s used to compare the mean values of two sets of data
What would you use a Spearman‘s rank test for?
It is used to consider the relationship between two sets of data
What are adaptations?
Adaptations are characteristics that increase and organisms chance of survival and reproduction and its environment.
What are three different types of adaptations?
Anatomical adaptations
Behavioural adaptations
Physiological adaptations
Name some examples of anatomical adaptations?
Mimicry
Camouflage
Shape and type of teeth
Body coverings e.g. fur or feathers
What adaptations does Marram grass have to its environment?
Curled or rolled leaves
Hairs on the inside surface of the leaf to trap moist air reducing the concentration gradient
Stomata sunken into pits
A thick waxy cuticle on leaves and stems
ALL TO REDUCE TRANSPIRATION
Name some examples of behavioural adaptations?
Survival behaviours
Courtship
Seasonal behaviours including migration and hibernation
What are the two categories of behavioural adaptations?
Innate
Learned behaviour
Name some examples of physiological adaptations?
Poison production
Antibiotic production
Water holding
What is analogous structure?
Structures that perform the same function but have different genetic origins.
What is convergent evolution?
When unrelated species begin to share certain traits. These evolve because organisms adapt to similar environments or similar selection pressures.
Examples of convergent evolution?
Marsupial and Placental Mice
Flying Phalangers and flying Squirrels
Marsupial and placental moles
What are selection pressures?
Factors that affect the organisms chances of survival or reproductive success.
Explain the process of natural selection?
Organisms show variation in characteristics caused by genetic variation - differing alleles.
Organisms whose characteristics are beneficial to their environment have an increased chance at survival.
Organisms reproduce and pass on the advantageous allele to their offspring.
This repeats for every generation, therefore frequency of advantageous allele increases in the populations gene pool.
This can lead to evolution of new species in the long run.
How is MRSA an example of evolution?
MRSA has become resistant to many antibiotics, the bacteria reproduce very rapidly. A mitigation is S.aureus provided resistance to methicillin. Resistant individuals survived and reproduced passing the resistance allele on.
How are peppered moths an example of evolution?
Pre industrial revolution moths were pale. Then during IR the trees became darker due to soot and due to the loss of lichen. The dark moths that were previously non competitive were now the fittest, highly camouflaged. The allele for the dark colouring was passed on through the population increasing the gene pool for black moths.
Recently this has reversed as most trees are light coloured again.
How do sheep bow flies exhibit evolution?
Became resistant to pesticide diazinon. The allele for this resistance was passed on and a resistant population evolved.
What is the founder effect?
When a few individuals of a species colonise a new area, initially a loss of variation is experienced, often resulting in individuals that are physically and genetically different from their source population.
What do flavobacterium do?
One strain uses enzymes to digest the nylon in the waste water that they live in. This has been used to help clear up factory waste
