4.5 Species and taxonomy Flashcards
Define species
- Organisms with shared characteristics that can interbreed to produce fertile offspring
Why doesn’t the definition of a species work
- Doesn’t fit for single-celled organisms since they don’t interbreed
- There’s a lot of variation between individuals in a species (e.g. in dogs)
Even where groups of extinct organisms have left fossils records, it is very difficult to distinguish different species. Suggest 2 reasons why
- Can’t interbreed fossils to see whether they produce fertile offspring
- Not all characteristics can be observed
- Fossil records are pretty incomplete
What is the behaviour of members of the same species like
It’s more alike than that of members of different species
Suggest why it’s often difficult to classify organisms as distinct species
Variation within a species is very large
How does organisms of the same species acting in a similar way beneficial to the organisms
Individuals can recognise member of the same species by the way they act
How is the ability to display behave determined
Genetically determined
What 5 things do courtship behaviours do that enables successful mating and that the offspring have the max chance of survival
- Recognise member of their own species
- Identify a mate that is capable of breeding
- Form a pair bond
- Synchronise mating
- Become able to breed
Why does the fact that courtship behaviours help individuals recognise member of their own species , ensure that mating is successful
It ensures that mating only takes place between members of the same species because only members of the same species can produce fertile offspring
Why does courtship behaviours enabling identification of a mate that is capable of breeding beneficial
Since both partners need to be sexually mature, fertile and receptive to mating
Why does courtship behaviours forming a pair bond beneficial
Since this bond will lead to successful mating and raising of an offspring
Why does courtship behaviour enabling synchronised mating beneficial
It takes place when there is the maximum probability of the sperm and egg meeting
Why does courtship behaviours enabling individuals become able to breed beneficial
By bringing members of the opposite sex into a physiological state that allows breeding to occur
What is courtship behaviours in humans
Foreplay
Explain how courtship behaviours enables successful mating
- identify their own species
- Synchronises mating and therefore increased the chance of offspring reaching reproductive age
- Female being receptive
- Creating a pair bond which increase the chance of fertile offspring and raising offspring
What are the 2 reasons why taxonomy is needed
- Predict characteristics
- Evolutionary relationships
What is the term of biological classification
Taxonomy
What are the 3 categories the 5 kingdom classification create
- Cell type
- Organisation of cells
- Nutrition
What is the order of the hierarchical system
- Kingdom
- Phylem
- Class
- Order
- Family
- Genus
- Species
What is meant when saying the hierarchical system groups are discrete
The groups don’t overlap
In the hierarchical system are the smaller groups have more in common or the larger groups
The smaller groups
What’s the kingdom of humans
Animals
What is the phylem of humans
Chordates
What is the class of animals
Mammals
What is the order of humans
Primates
What is the family of humans
Homonids
What is the genus of humans
Homo
What is the species of humans
Sapien
In the binomial naming system what 2 categories are used
Genus followed by the species
What language is the binomial system in
Latin
What is implied when the first word of the binomial system but the 2nd word is different for 2 organisms
The genus is the same but the species is different which implies evolution relationships
When writing the binomial system names, where is the capital letter and where is the lower case, write the human one
Capital letter of genus
Lower case of species
Homo sapien
What must you do when writing binomial system names
Underline when written by hand
What do phylogenetic trees show
Shows the evolutionary relationships
In a phylogenetic tree, what is the name of when the 2 lines split
- Points of divergence
- Common ancestors
What is the name of the line from the original ancestor to the end of the branch in a phylogenetic tree
Line of descent
What are homologous structures
Features with the same fundamental structure but different function
Homologous structures show what type of evolution
Divergent evolution
Name an example of homologous structures
Pentadactyl limbs
What are analogous structures
Different fundamental structures but same function
Analogous structures show what type of evolution
Convergent evolution
Are homologous structures or analogous structures used to provide evidence of common ancestors
Homologous structures
What is convergent evolution
When different organisms with not necessarily common ancestors come together at the same place
What is an extremophile
Organisms that can live in extreme environmentally conditions
How are domains separated
Different rRNA base sequence
Are eubacteria, archaea or eukaryota extremophiles
Archaea
Where does domain come in the hierarchical system
Before kingdom
What is genetic fingerprinting
The examination of VNTRS
What does VNTR stand for
Variable number tandem repeats
Where do you find VNTR
In the introns of human DNA
Roughly what % of DNA is introns
About 95%
What are introns
Non coding region of DNA
What is the probabiltity like of 2 individuals having the same VNTRs
Very low
When you’re closely related to someone, what are your VNTRs like
Get more similiar the more closley related you are
What does the analysis of VNTRs DNA fragments determine
The genetic relationships and the genetic variability within a population
What are the names of the 7 steps in order of genetic fingerprinting
- Collection
- Extraction
- Digestion
- Separation
- Hybridisation
- Development
- Analysis
Name 3 places where you might be able to collect the DNA sample for genetic fingerprinting
- Blood
- Body cells
- Hair follicles
What happens when the DNA you are sampling for genetic fingerprinting is very small
The DNA is cloned via PCR which is used to amplify the amount of DNA
Why do we need digestion when doing genetic fingerprinting
To cut the large sample up into all the different VNTRS within the organisms/ human
What is the name of the enzyme that digest/ cut the DNA during genetic fingerprinting into smaller fragments
Restriction endonucleases
When selecting the restriction endonucleases, what must their active site be complementary to in order to digest in the genetic fingerprinting
Complementary in shape to the sequence just before the VNTRS
Why must the restriction endonucleases active be complementary in shape to the sequence just before the VNTRS when doing genetic fingerprinting
So the enzyme cuts the DNA just before and just after the VNTRS so the entire length of the VNTRS is maintained
Why do we need to separate out the VNTRS
So we can analyses which VNTRs the individual has
During the separation process of genetic fingerprinting, where are the DNA samples loaded into to in the agar gel
Into small wells
During the separation process of genetic fingerprinting, what type of liquid is poured over the top of the gel
A buffer liquid
During the separation process in genetic fingerprinting, what is applied to the agar gel that has a buffer liquid on top
An electrical voltage
What end of the gel has a negative charge in genetic fingerprinting
The end closest to the DNA
What end of the gel has a positive charge in genetic fingerprinting
The end furthest away from the DNA
Is DNA positively or negatively charged
Negatively charged
Why does DNA being negatively charged help to move the DNA down the agar gel in genetic fingerprinting
Since the end furthest away from the DNA in the wells is positively charged and opposite charges attract
What group in DNA makes DNA negatively charged
The phosphate group
What is the name of the stage when the electrical voltage is added to the agar gel inn genetic fingerprinting
Gel electrophoresis
What does the agar gel create when the DNA moves from the agar well towards the positive end of the gel in genetic fingerprinting
The agar gel creates resistance
Do the smaller or larger pieces of DNA travel faster and further along the gel during gel electrophoresis, when the agar gel is creating resistance
The smaller pieces of DNA / The smaller length VNTRS
What does the different distance travelled through the agar gel during gel electrophoresis do
It separates the different lengths of DNA VNTRS
What is added to the agar gel after the VNTRS have been separated during gel electrophoresis
An alkaline
Why is an alkaline added to the agar gel after the separation of VNTRS during gel electrophoresis
To separate the double strands of DNA into single strands
What is hybridisation
Adding a different piece of DNA to the DNA that is in the agar gel - so you are left with a hybrid piece of DNA
What is the name of the DNA that is added to the single stranded DNA in the agar gel
DNA probes
What is a DNA probe
Short, single stranded pieces of DNA complementary in base sequence to the VNTRS and they are always labelled
What are the 2 usual things that a DNA is labelled with
- Radioactive chemical
- Fluroescent chemical
Are the DNA probes that are added to the single stranded DNA in the agar gel different or the same
DIfferent DNA probes
After adding the DNA probes to the agar gel, what happens
We wash the gel to remove any unbinded DNA probes
What is meant by the development stage in genetic fingerprinting
How we visualise the position of the VNTRS
In the development stage in genetic fingerprinting, what are the hybrid DNA transferred on to
A nylon sheet
Why are the hybrid DNA transferred onto a nylon sheet in the development stage of genetic fingerprinting
Since when the agar gel is taken out of the buffer liquid the gel will shrink and crack as it dries which wouldn’t produce a clear image so tranfer onto the nylon sheet so the DNA lasts longer
What determines which development method is used to develop the image from the nylon sheet
The label on the DNA probe
If the DNA probe was labelled using a radioactive label how is the nylon sheet developed
Expose the sheet to x-rays
If the DNA probe was labelled using a fluorescent label how is the nylon sheet developed
Expose the sheet to UV light
When the nylon sheet is exposed to x-ray what colour are the bands
Black and white
When the nylon sheet is exposed to UV light what colour do the DNA probes attached to the VNTRS glow
A greeny / yellow colour
When analysing the developed hybrid DNA, what is always put into the picture
A marker
What is the marker in the analysis of VNTRS
A DNA sample with VNTRS of known lengths is put into the first well
When analysing the genetic fingerprinting, what are you commparing
The position of the DNA bands
How does genetic fingerprinting help in paternity tests
- The child’s DNA will contain VNTRS from the mother and some from the father
- Line up the mothers’s and child’s
- So any band in the child that doesn’t match up with the mother must have come from the father
- So the father can be identified
What are 3 uses of genetic finger printing
- Medical diagnosis
- Forensic science to place suspects at crime scenes / paternity tests
- To ensure animals and plants are not closely related before being breed
How does genetic finger printing help with medical diagnosis
- Examine someones DNA
- And see if they have VNTRS in the positions which are expected or known to be in those positions of individuals who suffer from a particular genetic diesease
How does genetic fingerprinting ensure that animals and plants are not closely related before breeding
- Take 2 organisms that you want to breed
- Examine their genetic fingerprint
- And make sure their VNTRS are not too similar
Why do people need to check the genetic finger print of 2 organisms to ensure they aren’t too closely related before breeding
It reduces the risk of passing on genetic conditions / harmful genetic conditions
What are the 6 pieces of evidence that shows shared ancestry for all life
- All have DNA or RNA as their genetic material
- The genetic code is universal - same codon on mRNA for an amino acid
- The proteins in all organisms are formed from the same 20 amino acids
- ATP is the universal molecule for energy
- All have phospholipid membranes
- Vital physiological processes follow very similar metabolic pathways in all organisms
What 3 comparisons of genetic diversity can be used to classify organisms
- Base sequence of DNA
- Base sequence of mRNA
- Amino acid sequence
Other than hunting, suggest 2 reasons why populations might show very low levels of genetic diversity
- Populations might have been very small / genetic bottleneck
- Populations might have started with small number of individuals
- Interbreeding
What is meant by genetic diversity
Number of different alleles of each gene
Give 2 ways the student would have ensured their index of diversity was representative of each habitat (2 marks)
- Random samples;
- Large number (of samples)
OR
(Continue sampling) until stable running mean;
