2.1 Biodiversity and classification

Question 1

Define classification

Answer 1

The process of naming and organising organisms into groups based on their characteristics and evolutionary history.

Question 2

Can the classification of an organism change?

Answer 2

Yes, the classification of an organism may change as new information becomes available.

Question 3

Name the seven groups in the hierarchy of taxons, from largest to smallest.

Answer 3

Kingdom → Phylum → Class → Order
→ Family → Genus → Species

Question 4

What is the five kingdom classification system?

Answer 4

The classification of organisms into five major kingdoms: Animalia, Fungi, Plantae, Prokaryotae and Protoctista.

Question 5

What is the three domain classification system?

Answer 5

A method of classification in which organisms are categorised into three groups; Archaea, Bacteria and Eukarya.

Question 6

How was the three domain system of classification developed?

Answer 6

• By analysing molecular differences between organisms to determine their evolutionary relationships

• Evidence showed that the kingdom ‘prokaryotae’ could be divided into two groups. All other organisms are eukaryotes.

Question 7

What do organisms in the same domain have in common?

Answer 7

Organisms in the same domain share a distinctive pattern of ribosomal RNA.

Question 8

What is Bacteria?

Answer 8

• One of the three domains
• Consists of ‘true’ bacteria
• Also known as Eubacteria

Question 9

What is Archaea?

Answer 9

• One of the three domains
• Made up of primitive bacteria existing in extreme environments, e.g. extremophile prokaryotes
• Also known as Archaebacteria

Question 10

What is Eukarya?

Answer 10

• One of the three domains
• Consists of all eukaryotic organisms

Question 11

Outline the features of the kingdom Prokaryotae.

Answer 11

• Unicellular prokaryotes
• Lack a true nucleus and membrane-bound organelles
• Rigid cell wall

Question 12

Outline the features of the kingdom Plantae.

Answer 12

• Multicellular eukaryotes
• Photoautotrophs
• Cellulose cell walls

Question 13

Outline the features of the kingdom Animalia.

Answer 13

• Multicellular eukaryotes
• No cell wall
• Heterotrophic
• Nervous coordination

Question 14

Outline the features of the kingdom Fungi.

Answer 14

• Eukaryotes
• Heterotrophic
• Chitin cell walls
• Grow by producing branching filaments, hyphae
• Asexual reproduction via spores

Question 15

Outline the features of the kingdom Protoctista.

Answer 15

• Mainly unicellular eukaryotes
• No differentiation into tissues

Question 16

How are different types of evidence used in classification?

Answer 16

• Observations (e.g. fossils) - organisms grouped based on similar physical characteristics.

• Biochemical methods (e.g. DNA genetic fingerprinting)

Question 17

What is DNA profiling?

Answer 17

• Method of determining the characteristics of an individual’s DNA

• Percentage of DNA or proteins
shared between species is used to estimate relatedness

Question 18

State the advantage of using biochemical methods of classification.

Answer 18

Biochemical methods reduce mistakes made from observing physical features alone (due to morphological convergence).

Question 19

Compare homologous and analogous features.

Answer 19

• Homologous features have evolved from the same structure for different functions. They indicate a common ancestor

• Analogous features are structures that have evolved independently for the same function

Question 20

Give an example of a homologous feature.

Answer 20

Pentadactyl limb (found in mammals, birds and reptiles).

Question 21

Give an example of an analogous feature.

Answer 21

The wings of birds and insects.

Question 22

Define species.

Answer 22

A group of organisms that can interbreed to produce fertile offspring.

Question 23

What are the two components to a binomial name?

Answer 23

• Generic name - the Genus to which the organism belongs (Capitalise this one!)

• Specific name - the species the organism belongs to

Question 24

What is the advantage of the binomial naming system?

Answer 24

It is universal; an organism’s binomial name is the same everywhere in the world.

Question 25

Define biodiversity.

Answer 25

• The number and variety of living organisms in a given region

• It is affected by environmental, genetic and human factors

Question 26

What mechanism has generated biodiversity?

Answer 26

Natural selection

Question 27

When measuring the biodiversity of a habitat, what must ecologists consider?

Answer 27

• Species richness
• Species evenness

Question 28

Define species richness.

Answer 28

The number of different species found within an area.

Question 29

Define species evenness.

Answer 29

The number of individuals of each species living together in a community.

Question 30

How can biodiversity in a habitat be assessed?

Answer 30

Using Simpson’s Diversity Index.

Question 31

What is Simpson’s Diversity Index?

Answer 31

• A measurement of diversity that considers both species richness and evenness

• A value between 0 and 1 is found

• The closer the value is to 1, the greater the biodiversity

Question 32

How can we calculate genetic diversity within a species?

Answer 32

Proportion of polymorphic gene loci =
number of polymorphic gene loci/
total number of loci

Question 33

What is polymorphism?

Answer 33

The presence of different phenotypes among members of a single species.

Question 34

How can biodiversity be assessed at the molecular level?

Answer 34

Using DNA fingerprinting and sequencing.

Question 35

What is DNA sequencing?

Answer 35

Determining the entire DNA nucleotide base sequence of an organism.

Question 36

How is DNA sequencing used to measure biodiversity?

Answer 36

Comparisons between members of the same species can identify variation in base sequences and hence estimate genetic diversity.

Question 37

What is an adaptation?

Answer 37

A feature of an organism that increases its chance of survival in its environment.

Question 38

Describe the three types of adaptation.

Answer 38

• Anatomical - changes to physical features

• Physiological - changes to bodily processes

• Behavioural - changes to actions

Question 39

Outline the procedure to this practical.

Answer 39

1. Choose an area to take samples from. Use a random number generator to generate 10 sets of random coordinates.
2. Use two tape measures to create a set of axes off which coordinates can be read.
3. Place the quadrat at each of the coordinates, placing the bottom left corner on the coordinate every time.
4. Record the number of individuals belonging to each species.
5. Repeat steps 1-4 at another site with a different environmental factor eg. mowed vs. unmowed grass

Question 40

State Simpson’s Index of Biodiversity.

Answer 40

D = 1 - [(n / N²)]

Question 41

What is species richness?

Answer 41

The number of different species in a community.

Question 42

What is species evenness?

Answer 42

The relative abundance of individuals of different species.

Question 43

Outline the procedure of sampling invertebrates.

Answer 43

1. Mark an area with a quadrat.
2. Place a net in the water held downstream of the quadrat.
3. Agitate the stream bed and ‘kick’ for a few minutes to sweep up some invertebrates.
4. Place the catch in a shallow white tray with 2 cm depth of fresh water from the stream or river.
5. Count the number of individuals of each species.
6. Return the animals into the stream.
7. Repeat for a total of 10 quadrats.

Question 44

State a hazard and safety precaution of this practical.

Answer 44

Certain plants may cause allergic reactions, avoid touching specimens and wear gloves if necessary.