Species & Taxonomy Flashcards
Define taxonomy
The study of biological classification
What does classification allow us to do
To organise a great diversity of life into smaller manageable groups
Define hierarchy
Where smaller groups are placed within larger groups with no overlaps between them
What are the taxonomic ranks in order
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Define domain
Eukaryotes, prokaryotes and archaea
Define kingdom
Animals, plants, fungi, prokaryotes, protactista
Define phylum
Based on body plan (eg vertebrate/invertebrate)
Define class
Diversity in each phyla (eg mammals, reptiles etc)
Define order
Further division within the common features of
Define family
Usually the same as the genus name
Ends in -dae
Define genus
Species evolved from a common ancestor
Define species
Interbreeding between organisms which can produce viable and fertile offspring
Species share a common ancestry and are similar in biochemistry and anatomy
What does a binomial name come from
Genus (1st) and species (2nd)
Define phylogeny
Evolutionary relationships between organisms
What is a phylogenetic tree
A tree like diagram that represents the phylogenetic relationships of different species
Suggest why 2 different species are unable to produce fertile offspring
Different species have different chromosome numbers. This could mean the offspring has an odd number of chromosomes, so homologous pairs can’t form and meiosis cannot occur to produce gametes
What is an advantage of binomial naming
It is universal so there is no confusion as many organisms have more than one common name
Explain why courtship behaviour is necessary for successful mating
It allows recognition of the same species, so fertile offspring can be produced
Allows recognition and attraction of the opposite sex
Stimulates/synchronises mating and the release of gametes
It indicates sexual maturity
It establishes a pair bond for a mother and father to raise their young
Describe a phylogenetic classification system
Species are arranged into groups (called taxa) based on their evolutionary origins (common ancestors) and relationships
The system uses a hierarchy where smaller groups are placed into larger groups with no overlap in between them
What is courtship behaviour important for
To help ensure successful mating as reproduction is essential
How does courtship help to achieve mating
It helps members recognise others within their species
Helps to identify a sexually mature mate
Helps to form a pair bond which is important when raising young
Helps with synchronising mating which helps to increase the probability of the sperm and egg meeting
What are the 3 main types of mating behaviours
Fighting
Scent
Dancing
What are the 2 advances that have helped to clarify evolutionary relationships between organisms
Advances in genome sequencing
Advances in immunology
Describe advances in genome sequencing
Genome sequencing allows for the comparison of DNA base sequences
The more differences in DNA base sequences the more distantly related organisms are
This is because mutations/changes in DNA base sequences build up overtime
Describe advances in immunology
Immunology allows for the comparison of a proteins tertiary structure
If a higher amount of protein from one species binds to an antibody against the same protein from another species, the more closely related they are
This is because it indicates a similar amino acid sequence and tertiary structure, so there is less time for mutations to build up
What are the methods of genetic comparison
Comparing mRNA base sequences
Comparing DNA base sequences (DNA hybridisation)
Comparing amino acid sequences (Immunological comparison of proteins)
What is the process of DNA hybridisation
1) Takes the DNA of 2 species and heat them to break the hydrogen bonds between the bases, creating single strands
2) Mix the single strands together
3) Let the strands cool down so that the hydrogen bonds can reform between the complementary base pairs
4) If there are lots of pairs formed, we know that the species are genetically similar
How do we know if species are similar based on DNA hybridisation? How does this differ for distantly related species
If there are lots of pairs formed
This is because closely related species will have sequences which differ at only a few base sites
Distantly related species will have different bases at many sites and may be different lengths too
How can we compare DNA/mRNA base sequences
Use computer software to compare
Similar sequences may suggest organisms are closely related
Why is it easier to isolate mRNA than DNA
Because mRNA is found in the cytoplasm and there is lots of copies of it
Why is comparing amino acid sequences not acs accurate
Because of the degenerate nature of the genetic code
Describe immunological comparisons on proteins
1) Blood containing protein from species A is injected into species B
2) Species B will have an immune response and will make antibodies for the blood protein from species A
3) Blood serum from species B that contains the antibodies is mixed in with blood taken from species C
4) Antibodies respond to any corresponding antigen within the blood of species C and then a solid precipitate forms
5) The stronger the precipitate, the more closely related species A and C are
