A11 SPECIES AND TAXONOMY

What is the definition of taxonomy?

the science of classification, involving naming and grouping organisms according to shared characteristics

What is the definition of species?

a group of similar organisms able to reproduce and produce fertile offspring

What’re the 8 levels of taxa?

1. Domain

2. Kingdom

3. Phylum

4. Class

5. Order

6. Family

7. Genus

8. Species

What is the definition of a hierarchy?

smaller groups which are contained within larger groups with no overlap

What is the binomial naming system?

each species has a two word scientific name, containing the genus and then species name

What’re characteristics of the binomial naming system?

• universal

• based on latin or greek names

• written in italics and underlined

• first letter of the first word is capitalised

What is phylogenetics?

the study of patterns of evolutionary history

How are evolutionary relationships often displayed?

• in a phylogenetic tree

• organisms sharing a common ancestor more recently have branches which are closer together

What is courtship behaviour?

carried out by organisms to attract a mate of the right species, as it is species specific

How does courtship behaviour increase the probability of successful mating?

• species specific as it allows for identification of members of the same species

• courtship behaviour of males and females of the same species will differ allowing them to recognise members of the opposite sex

• indicates sexual maturity and readiness of mate

• help form a pair bond which increases the chance of offspring surviving to maturity

• synchronise mating

Why is it difficult to observe some courtship behaviour?

as species may be: extinct

• produce asexually

• have practical or ethical issues

How are genetic comparisons made?

using: DNA

• RNA

• primary structure of proteins

What occurs when comparing DNA base sequence?

• yields the most information for comparing between 2 species

• more closely related the species thee more similar their DNA base sequence

• compares all bases whether introns or exons

• differences are due to random genetic mutations or silent mutations

What occurs when comparing mRNA base sequence?

• yields some information

• any differences are due to random genetic mutations

• compares only exons so any mutations in the introns will not be detected

What occurs when comparing amino acid sequences of a protein common to all the species?

• yields the least information between 2 species

• any differences are due to random mutations

• compares only the primary sequence of amino acids in a protein and will not detect silent mutations due to the degenerate nature of DNA

• compare a common protein across the species e.g. haemoglobin

• more differences means more mutations so more time has passed since a common ancestor was shared