Topic 3

Question 1

Taxonomic groups

Answer 1

Domain -> kingdom-> phylum-> class-> order -> family -> genus -> species

Question 2

Morphological species concept and evaluation.

Answer 2

Study of the structures of organisms ignoring DNA.

Based only on appearance and phenotype. Vague.
Sexual dimorphism: there is great difference between appearance of male and female of same species.
analogus structures: similar structures but they have not developed from the same evolutionary origin. e.g bat wings and insect wings

Question 3

reproductive species concept and evaluation.

Answer 3

Group of organisms with similar characteristics, that reproduce fertile offspring

Does not consider asexual reproduction.
geographical isolation may prevent members of the same species from interbreeding.
Some members of different species can interbreed to produce fertile offspring.
Hybridisation in plants.

Question 4

Ecological species concept and evaluation.

Answer 4

Based on the ecological niche occupied by an organism. it acknowledges the role of the environment.

not a robust way of identifying species as niche definitions vary and many species occupy more than one niche.

Question 5

Mate recognition species concept and evaluation

Answer 5

When a species recognises each other for reproduction

Does not consider asexual reproduction.
many species interbreed with each other.
Hybridisation in plants

Question 6

Genetic species concept and evaluation

Answer 6

based on DNA evidence to determine different species

Historically collecting DNA was difficult and expensive.
it is still subjective, as people still have to decide how much genetic difference makes two organisms members of different species.

Question 7

Evolutionary species concept and evaluation

Answer 7

based on shared evolutionary relationships between species.

Not easy to apply as there is not always a clear evolutionary path.

Question 8

Bionformatics

Answer 8

Bioinformatics: the development of software and computing tools needed to organise and analyse raw biological data, including the development of algorithms, mathematical models and statistical tests that help us to make sense of the enormous quantities of data being generated.

barcoding involves looking at short genetic sequences from a part of the genome common to particular groups of organisms.
Development of field instruments that can analyse genes and identify species faster should help scientists deal with the threat of invasive species.
DNA profiling: process by which non coding areas of DNA are analysed to identify patterns.
DNA sequencing: process by which the base sequences of all or part of the genome of an organism is worked out.
This means organism can be classified more easily.

Question 9

The role of the scientific community

Answer 9

Scientific journals: scientific findings are not widely accepted by the scientific community unless they are published in a journal. It is an easy and clear way to show scientific findings.
Peer review process: the process by which scientific papers are sent to other scientists who are experts in the field, for them to read and assess before publication in a journal.
Conferences: scientists share data, discuss ideas and listen to a number of presentations on the same area of work. Allow scientists to take a critical look at other work in their field, and collaborate together.

Question 10

Three domains

Answer 10

bacteria, archaea, eukaryota

Question 11

6 kingdoms

Answer 11

bacteria. archaea. protista, plantae, fungi, Animalia.

Question 12

5 kingdom system

Answer 12

Monera. protista, plantae, fungi, Animalia.

Question 13

What system is used and why?

Answer 13

Today a 3 domain and 6 kingdom system is used.
This is because Monera was split into bacteria (aka Eubacteria) and Archaebacteria.
This is because it was found that archaebacteria are more closely related to eukaryota than modern eubacteria. This was found using biochemical and DNA evidence.

Question 14

Differences between threee domains

Answer 14

Bacteria and Archaea = 70s ribosomes. Eukaryota = 80s ribosomes.
bacteria and eukaryota = ester linked, unbranched membrane lipids. Archae = ester linked branched membrane lipids.
bacteria = peptidoglycan in cell walls.
Eukaryota = membrane enclosed nucleus and organelles.

Question 15

Endosymbiotic theory

Answer 15

This shows how eukaryotes evolved from prokaryotes.
Cell engulfs aerobic prokaryote as food.
By chance it is not digested. It uses O2 for respiration = cells grow and reproduce more rapidly
Aerobic prokaryotes become permanent feature as mitochondria or chloroplast.
Hence explains why they have membrane and DNA and can replicate individually from the cell.

Question 16

Natural selection

Answer 16

There is variation within species due to mutations, sexual reproduction (meiosis + random fertilisation). Environmental change causes there to be a change in selection pressure.
Therefore individuals which are poorly adapted die and do not reproduce. Hence the frequency of their unfavourable gene decreases.
Individuals which are well adapted survive and reproduce to pass on their advantageous alleles. Hence the gene frequency increases.
This means EVOLUTION takes place as there is a change in the population of a species.

Question 17

Niche

Answer 17

A niche is the role of an organism within the habitat in which it lives.

Question 18

Types of Adaptations

Answer 18

Anatomical adaptations: an adaptation involving the form and structure of an organism.
Physiological adaptation: an adaptation involving the way the body of the organism works, including difference in biochemical pathways or enzymes.
Behavioural adaptation: an adaptation involving programmed or instinctive behaviour making organism better adapted for survival.

Question 19

Allopatric speciation

Answer 19

Allopatric speciation: speciation that takes place when population are physically or geographically separated and there can be no interbreeding or gene flow between populations.

Question 20

Sympatric speciation

Answer 20

Sympatric speciation: speciation that takes place between two populations of a species living in the same place. They become reproductively isolated by mechanical, behavioural or seasonal mechanism and gene flow continues between the populations to some extent as speciation takes place.

Question 21

Adaptive radiation

Answer 21

Adaptive radiation: a process by which one species evolves rapidly to form a number of different species that all fill different ecological niches. e.g Darwin’s finches. different beak types feeding on different sources.

Question 22

Why is antibiotic resistance increasing?

Answer 22

Antibiotics are too widely prescribed and used
Wide-spectrum antibiotics are often used to make sure they have an effect, rather than testing to determine if an infection is bacterial and if so which bacteria are involved.
People do not complete courses of antibiotics, which makes it easier for resistance to develop.
In some countries antibiotics are widely used in the food chain.
A lack of basic hygiene in hospitals and care homes has encouraged the spread of antibiotic resistant organisms such as MRSA.
There is no big financial incentive for pharmaceutical companies to develop new antibiotics as new antibiotics will be used sparingly to prevent the development of resistance.

Question 23

Solutions to increasing antibiotic resistance

Answer 23

Reduce the use of antibiotics
Better education so people understand they do not always need antibiotics
Reducing use of antibiotics in farm animals.
Development of new antibiotics.
DNA sequencing will help identify bacteria, and find new ways of targeting them without antibiotics.

Question 24

How can biodiversity be measured?

Answer 24

Species Richness: The number of different species in an area

Species Abundance: Relative number of different types of organisms. (It is an area showing an even abundance different species is considered to be more biodiverse than one containing the same number of different species but dominated by one or two of the species.)

Endemism: The number of species found in an area, that are ONLY found in that area.

Question 25

Reasons to maintain biodiversity

Answer 25

To give the same biodiversity to future generations
a source of enjoyment for many
it is unethical to cause the extinction of species and loss of genetic diversity through human activity
source of employment of many. e.g park rangers

provisioning services: ecosystems providing services e.g food, fibres for clothing water etc
Regulating services: ecosystems maintain and regulate our environment. e.g water purification, maintaining air quality.
Supporting Services: ecosystems provide support for other ecosystem services we need. e.g soil formation and nutrient recycling are needed to grow food.
Cultural services: e.g tourism, recreation.

Question 26

Ex situ conservation

Answer 26

the conservation of biological diversity outside their natural habitats. Works as a complementary approach to in-situ conservation.
Botanic gardens and seed banks to conserve plants.
Captive breeding programmes, with the ultimate aim to reintroduce animals to the wild.

Question 27

In situ conservation

Answer 27

the conservation of ecosystems and natural habitats and the maintenance and recovery of viable populations of species in their natural surroundings.
national parks, habitat restoration, strategies for the sustainable use and management of biological resources.