Classification

Question 1

Define a species

Answer 1

Population of organisms which are capable of breeding to produce fertile offspring.

Question 2

Why is there not a definite, simple definition of a species?

Answer 2

Some organisms have changed and evolved.

Some organisms live far away from each other and cannot show interbreeding

Some organisms can produce viable, but not fertile offspring

Question 3

How can courtship behaviour show the relationship between species?

Answer 3

Behaviour of closely related species is more similar than those of different species

Ability to display a behaviour is genetically determined

Question 4

What are simple courtship behaviours?

Answer 4

Visual displays

Releasing a chemical

Different sounds

Question 5

What are complex courtship behaviours?

Answer 5

Building

Dancing

Question 6

What are some advantages of courtship behaviours?

Answer 6

Recognise members of their own species to ensure fertile offspring produced

To identify a male that is capable of breeding as both partners must be sexually mature

Form a pair bond which leads to successful mating and raising of offspring

Question 7

What are the two types of classification?

Answer 7

Artificial

Phylogenetic

Question 8

Define artificial classification

Answer 8

Divides organisms according to differences that are useful at the time (such as colour). Analogous characteristics that have the same function but different evolutionary origins

Question 9

Define Phylogenetic Classification

Answer 9

Based upon evolutionary relationships between organisms and their ancestors. Classifies species into groups using shared features derived from their ancestors. Arranges groups into a hierarchy

Question 10

What is a hierarchy?

Answer 10

Where groups are contained within larger composite groups with no overlap.

Question 11

Name each Taxa used in the Linnaeus Classification System

Answer 11

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species

Question 12

What are the three domains?

Answer 12

Bacteria

Archaea

Eukarya

Question 13

Describe the features of members of the bacteria domain

Answer 13

No membrane bound organelles

Ribosomes are smaller than those in eukaryotes

Cell walls are present and made of murein

DNA is not associated with histones

Question 14

Describe the features of members of the archaea domain

Answer 14

No murein in their cell walls

No membrane-bound organelles

Ribosomes are smaller than those of eukaryotes

Question 15

Describe the features of members of the eukarya domain

Answer 15

Membrane-bound organelles

If cell walls are present, they are made of cellulose or chitin

Ribosomes are larger than those in bacteria and archaea

Question 16

Describe the features of Carl Linnaeus’ binomial naming system

Answer 16

Names written in italics or underlined

First part of the name is the genus and has a capital letter

Second part of the name is the species and has a lowercase letter

Question 17

Define phylogeny

Answer 17

The study of the evolutionary history of groups of organisms

Question 18

How can evolutionary relationships be clarified?

Answer 18

Genome sequencing

Comparing amino acid sequences

Immunological comparisons

Question 19

How does sequencing the genome tell us how closely related species are?

Answer 19

The fewer differences between the base sequences of two species, the more closely related those two species are.

Question 20

How does the difference in amino acid sequence tell us how closely related species are?

Answer 20

The fewer the differences between the amino acid sequence of a specific protein of two species, the more closely related the two species are.

Haemoglobin is a good example

Question 21

How do immunological comparisons tell us how closely related species are?

Answer 21

Based on human blood proteins

Uses rabbit antibodies against human blood proteins

Measures agglutination levels, the more similar the agglutination value, the more closely related the species are.

Question 22

What are the six different ways of classifying organisms?

Answer 22

Comparison of:

Observational features

Courtship techniques

DNA base sequence

Immunological aspects

Amino acid sequence

Question 23

Describe the process of DNA hybridisation

Answer 23

Sections of DNA are removed from two organisms

Samples are heated to high temperatures so Hydrogen bonds between DNA strands separate

Samples are then allowed to combine under cool conditions

If full hybridisation occurs, the DNA strands from the separate organisms combine fully and we say that they are the same species, or very closely related.

If partial hybridisation occurs, DNA strands combine, but not fully, we say the organisms have a close relationship

If no hybridisation occurs, DNA strands do not combine, they have no relation, or very distantly related.

Question 24

How has gene technology changed to work out relationships between species?

Answer 24

Early days - visual features observed in a population, and numbers of organisms with that particular feature

Now - different alleles determine different characteristics, so a wide variety of each characteristic indicates high allele number and thus genetic diversity.

Question 25

Biochemical techniques give a much more _______ estimate of genetic diversity

Answer 25

Accurate