Species & Taxonomy

Question 1

Define taxonomy

Answer 1

The study of biological classification

Question 2

What does classification allow us to do

Answer 2

To organise a great diversity of life into smaller manageable groups

Question 3

Define hierarchy

Answer 3

Where smaller groups are placed within larger groups with no overlaps between them

Question 4

What are the taxonomic ranks in order

Answer 4

Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

Question 5

Define domain

Answer 5

Eukaryotes, prokaryotes and archaea

Question 6

Define kingdom

Answer 6

Animals, plants, fungi, prokaryotes, protactista

Question 7

Define phylum

Answer 7

Based on body plan (eg vertebrate/invertebrate)

Question 8

Define class

Answer 8

Diversity in each phyla (eg mammals, reptiles etc)

Question 9

Define order

Answer 9

Further division within the common features of

Question 10

Define family

Answer 10

Usually the same as the genus name
Ends in -dae

Question 11

Define genus

Answer 11

Species evolved from a common ancestor

Question 12

Define species

Answer 12

Interbreeding between organisms which can produce viable and fertile offspring
Species share a common ancestry and are similar in biochemistry and anatomy

Question 13

What does a binomial name come from

Answer 13

Genus (1st) and species (2nd)

Question 14

Define phylogeny

Answer 14

Evolutionary relationships between organisms

Question 15

What is a phylogenetic tree

Answer 15

A tree like diagram that represents the phylogenetic relationships of different species

Question 16

Suggest why 2 different species are unable to produce fertile offspring

Answer 16

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

Question 17

What is an advantage of binomial naming

Answer 17

It is universal so there is no confusion as many organisms have more than one common name

Question 18

Explain why courtship behaviour is necessary for successful mating

Answer 18

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

Question 19

Describe a phylogenetic classification system

Answer 19

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

Question 20

What is courtship behaviour important for

Answer 20

To help ensure successful mating as reproduction is essential

Question 21

How does courtship help to achieve mating

Answer 21

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

Question 22

What are the 3 main types of mating behaviours

Answer 22

Fighting
Scent
Dancing

Question 23

What are the 2 advances that have helped to clarify evolutionary relationships between organisms

Answer 23

Advances in genome sequencing
Advances in immunology

Question 24

Describe advances in genome sequencing

Answer 24

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

Question 25

Describe advances in immunology

Answer 25

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

Question 26

What are the methods of genetic comparison

Answer 26

Comparing mRNA base sequences Comparing DNA base sequences (DNA hybridisation) Comparing amino acid sequences (Immunological comparison of proteins)

Question 27

What is the process of DNA hybridisation

Answer 27

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

Question 28

How do we know if species are similar based on DNA hybridisation? How does this differ for distantly related species

Answer 28

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

Question 29

How can we compare DNA/mRNA base sequences

Answer 29

Use computer software to compare Similar sequences may suggest organisms are closely related

Question 30

Why is it easier to isolate mRNA than DNA

Answer 30

Because mRNA is found in the cytoplasm and there is lots of copies of it

Question 31

Why is comparing amino acid sequences not acs accurate

Answer 31

Because of the degenerate nature of the genetic code

Question 32

Describe immunological comparisons on proteins

Answer 32

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