Classification Flashcards
Why do we classify organisms
For convenience
To make studying similar organisms easier
See relationships between organisms
What are the 8 taxonomic classes
Domain Kingdom Phylum Class Order Family Genus Species
What is the binomial system
A way of naming an organism
Consists of the Genus and species
E.d Homo Sapiens
What is the biological definition of a species
A group of organisms that can feely interbreed to produce fertile offspring
Why is the traditional taxonomic classification of 2 kingdoms not always accurate
because everything was grouped into plants or animals
somethings don’t fit in
Ergot fungus doesn’t move and has root like structurers (like a plant) but doesn’t photosynthesise and digests nutrients like an animal
What are the 5 new kingdoms in the taxonomic system
Prokaryotae
Protoctista
Fungi
Plantae
Animalia
What is Convergent evolution and how could it make observable feature classification inaccurate
Animals adapt and evolve to suit their environment
2 species could be completely unrelated but live in the same environment meaning they may have developed certain similar physical or behavioural traits.
How can biological molecules be used to determine phylogenic relationships
If we assume that early life all had the same biological molecule makeup then changes must be down to evolution
2 species with more similarities are more closely related
What is Cytochrome c
A protein that is used in respiration, so all living organisms that respire have it.
How is Cytochrome c used to find relationships between 2 species
Not all Cytochrome c molecules are the same
You can map the amino acid sequence of 2 organisms’ Cytochrome c protein and compare the differences
The more similarities the closer they are related
What is artificial classification
It is where you classify things only based on a few characteristics
Doesn’t reflect evolutionary relationships
What is Natural Classification
Involves a detailed study of the individuals you are trying to classify
Works in more detail
For example dog breeds look very different but biologically are very similar so are part of the same species
What was the name of Darwin’s mechanism that explained Evolution
Natural Selection
What is Darwin’s principle of ‘Survival of the Fittest’
It is a struggle to survive
Better adapted individuals have more chance of survival
They pass on these traits to their offspring
Over time many changes may lead to a nee species
How can DNA be used to prove evolutionary relationships
If you map the base sequences in the DNA
More similarities in the sequences mean that the individuals will have more common traits
It also means that there have been less mutations and thus the species only diverged relatively recently
Define intraspecific variation
Variation within a species
Define interspecific variation
Variation that occurs between species
What is the relationship between genetic diversity of a species and level of intraspecific variation
The greater the genetic diversity the greater the intraspecific variation
What is continuous variation
Where the data is a spectrum
There are 2 extremes and a full range of data between that
A vast majority are around the mean of the data
E.g Human height, length of leaves on an oak tree
Why is the number of individuals at the extremes of continuous variation small
Because traits that are represented by continuous variation are often controlled by more than 1 gene
What is discontinuous variation
Where there are 2 or more distinct categories with no intermediate values
Usually regulated by 1 gene
E.g. eye colour, gender, human blood groups
What is genetic variation
Variation in genes that we inherit off our parents
No 2 individuals are the same
Variations that we can’t control
However we share many genes with others in our species as well as other species
What is environmental variation
Characteristics that are caused by environment
Such as if you eat more you will weigh more, or if you spend time in the sun then your skin will tan and get darker
What is adaption?
Any variation that helps an organism to survive
What are the 3 types of adaptions?
Anatomical
Behavioural
Physiological
What are anatomical adaptions?
Any structural changes to an organism that help it survive
What are Behavioural adaptions?
A specific behaviour that helps an organism to survive
What are Physiological adaptions?
An adaptions that ensures the correct functioning of cell processes
Give examples of anatomical adaptions in marram grass
Long roots - reach more water
Wide spread roots - get more water when it rains
Curled leaves - reduces water loss by maintaining gradient
Lower epidermis has hair - reduces water loss
Low stomata density - reduces water loss
Thick waxy cuticle - reduces evaporation from cells
Give a behavioural adaption of marram grass
When water stress is high it rolls its leaf tighter and closes stomata
This maintains a low water potential outside the leaf which reduces water loss by transpiration
Give physiological adaptions of marram grass
Leaf can roll more or less due to specialised hinge cells in the lower epidermis
Guard cells can open and close stomata more easily
It maintains a lower water water potential than other plants allowing it to survive in salty conditions
Leaves have lignified cells that provide support when turgidity is lost
What is the name given to the process whereby 2 unrelated species share similar characteristics due to their environment?
Convergent Evolution
Outline the process of natural selection
Mutation creates alternate allele
Creates genetic intraspecific variation
This mutation may give a the species an advantage in their environment
If that is the case they are more likely to survive and are therefore more likely to pass this allele on
Over generations this allele will become more frequent in the population
