Flashcards in Species And Taxonomy Deck (18):
Members of the same species can breed with each other to produce living fertile offspring. Any of the genes of a species can be combined without any problems.
What does it mean for reproduction if two organisms are different species?
If two organisms are not the same species they either can not produce offspring or produce an infertile hybrid e.g. a zebra and a donkey produce an infertile hybrid called a zedonk. The reason this animals are infertile may be because their chromosomes are unable to pair up to under meiosis due to the odd number of chromosome so they can't form a fully functional gamete.
What is the binomial system?
The way organisms are named, the two name system. The first name is the generic name and this is the Genus to which the organism belongs. The second name is the specific name and this is the species.
What are the rules of the binomial system?
- the specific name is never shared with another species within the genus.
- the names are printed in italics or underlined if handwritten.
- the first letter of the genus is capitalised.
What are the types of classification?
Artificial and phylogenic.
What is artificial classification?
It divides organisms by physical characteristics such as size or number of legs. It's described by the same function not the evolutionary origin.
What is phylogenic classification?
It is also known as natural classification, it is based upon evolutionary relationships. It classifies species by using their species by using their shared features derived from their ancestors. It arranges the groups into a hierarchy.
Groups contained within larger groups with no overlap.
The science of classification. Each group within biological classification is called a tax on.
What is the hierarchy order?
Domain e.g. Eukarya
Kingdom e.g. Animals
Phylum e.g. Chordata
Class e.g. Mammals
Order e.g. Carnivora
Family e.g. Felidae
Genus e.g. Panthera
Species e.g. pardus
Name = Panthera pardus
How to remember the order of the hierarchy?
Dinner, Kind Prawn Curry or Fat Greasy Sausages
The phylogeny describes the evolutionary relationships between organisms. The closer the branches the closer the relationship. Molecular phylogeny describes the evolutionary and genetic relationships between organisms. Organisms with specific and common characteristics are placed into groups.
How do we find evidence for evolutionary relationships?
- comparing the frequency of measurable or observable characteristics
- comparison of DNA base sequences
- comparison of mRNA sequences
- comparison of amino acid sequences in proteins
- use of immunological advances to clarify evolutionary relationships
Comparing the frequency of measurable or observable characteristics?
Many characteristics are polygenic e.g. hair colour and it's hard to distinguish one variant from another e.g. Hair colour = gene 1 + gene 2
Comparison of DNA bases?
The recent ancestors will have very similar DNS to a new species. Therefore the fewer the base changes the closer than species are in, in evolutionary terms. Base changes are caused by mutations.
Comparison on mRNA bases?
mRNA is derived from the DNA base sequence via transcription. So like DNA the more similar the mRNA base sequence is between 2 species the more closely related they are.
Comparison of amino acids in proteins?
The sequence of amino acids in a protein is determined by the DNA therefore when comparing 2 species the more similar the amino acid sequence the more closely related they are.