AQA GCE Biology
3.2 Unit 2 BIOL2: The Variety of Living Organisms
3.2.10 Adaptation and selection are major components of evolution and make a significant contribution to the diversity of living organisms
Antibiotics may be used to treat bacterial disease. One way in which antibiotics function is by preventing the formation of bacterial cell walls, resulting in osmotic lysis.
Genetic variation in bacteria
DNA is the genetic material in bacteria as well as in most other organisms.
Mutations are changes in DNA and result in different characteristics.
Mutations in bacteria may result in resistance to antibiotics.
Resistance to antibiotics may be passed to subsequent generations by vertical gene transmission.
Resistance may also be passed from one species to another when DNA is transferred during conjugation. This is horizontal gene transmission. Antibiotic resistance in terms of the difficulty of treating tuberculosis and MRSA.
Candidates should be able to:
- apply the concepts of adaptation and selection to other examples
- evaluate methodology, evidence and data relating to antibiotic resistance
- discuss ethical issues associated with the use of antibiotics
- discuss the ways in which society uses scientific knowledge relating to antibiotic resistance to inform decision making.
Edexcel GCE Biology
Unit 4: The Natural Environment and Species Survival
21 Describe how evolution (a change in the allele frequency) can come about through gene mutation and natural selection.
22 Explain how reproductive isolation can lead to speciation.
23 Describe the role of the scientific community in validating new evidence (including molecular biology, eg DNA, proteomics) supporting the accepted scientific theory of evolution (scientific journals, the peer review process, scientific conferences).
16 Discuss how the theory of an ‘evolutionary race’ between pathogens and their hosts is supported by the evasion mechanisms as shown by human immunodeficiency virus (HIV) and Mycobacterium tuberculosis (TB).
OCR GCE Biology
3.5 A2 Unit F215: Control, Genomes and Environment
5.1.2 Meiosis and variation
(d) Explain how meiosis and fertilisation can lead to variation through the independent assortment of alleles;
(i) describe the differences between continuous and discontinuous variation;
(j) explain the basis of continuous and discontinuous variation by reference to the number of genes which influence the variation;
(k) explain that both genotype and environment contribute to phenotypic variation;
(l) explain why variation is essential in selection;
(m) use the Hardy–Weinberg principle to calculate allele frequencies in populations;
(n) explain, with examples, how environmental factors can act as stabilising or evolutionary forces of natural selection;
(o) explain how genetic drift can cause large changes in small populations;
(p) explain the role of isolating mechanisms in the evolution of new species, with reference to ecological (geographic), seasonal (temporal) and reproductive mechanisms;
(q) explain the significance of the various concepts of the species, with reference to the biological species concept and the phylogenetic (cladistic/evolutionary) species concept;
(r) compare and contrast natural selection and artificial selection.
WJEC GCE Biology
Unit BY5: Environment, Genetics and Evolution
5.5 Variation and evolution
(a) Genetic and environmental factors produce variation between individuals
- Variation may be continuous and discontinuous; heritable and nonheritable.
- Inter and intra-specific competition for breeding success and survival.
- Selective agencies (eg supply of food, breeding sites, climate).
- The gene pool and genetic drift.
- Selection can change the frequency of alleles in a population.
(b) Isolation and speciation
- Separation of populations by geographical, behavioural, morphological, seasonal and other isolation mechanisms.
- Hybrid sterility.
- Darwin's theory of evolution that existing species have arisen through modification of ancestral species by natural selection.
SQA Advanced Higher Biology
Biology: Organisms and Evolution
(i) Drift and selection: Processes of evolution, natural selection, sexual selection and genetic drift. Mutations can be harmful, neutral or beneficial and give rise to variation. Absolute fitness is the ratio of frequencies of a particular genotype from one generation to the next. Relative fitness is the ratio of surviving offspring of one genotype compared with other genotypes.
(ii) Rate of evolution: Where selection pressures are high, the rate of evolution can be rapid. The rate of evolution can be increased by factors such as shorter generation times, warmer environments, the sharing of beneficial DNA sequences between different lineages through sexual reproduction and horizontal gene transfer.
(iii) Co-evolution and the Red Queen Hypothesis: A change in the traits of one species acts as a selection pressure on the other species. Co-evolutionary ‘arms race’ between a parasite and host as an example of the Red Queen Hypothesis.
International Baccalaureate Diploma Biology
Topic 5: Ecology and Evolution
5.4.1 Define evolution
5.4.2 Outline the evidence for evolution provided by the fossil record, selective breeding of domesticated animals and homologous structures
5.4.3 State that populations tend to produce more offspring than the environment can support
5.4.4 Explain that the consequence of the potential overproduction of offspring is a struggle for survival
5.4.5 State that the members of a species show variation
5.4.6 Explain how sexual reproduction promotes variation in a species
5.4.7 Explain how natural selection leads to evolution
5.4.8 Explain two examples of evolution in response to environmental change; one must be antibiotic resistance in bacteria
Option D2: Species and Speciation
D2.2 State that evolution involves a change in allele frequency in a population’s gene pool over a number of generations
D2.8 Compare convergent and divergent evolution
Option D3: Human Evolution
D.3.7 Discuss the incompleteness of the fossil record and the resulting uncertainties about human evolution
D.3.8 Discuss the correlation between the change in diet and increase in brain size during hominid evolution
D.3.9 Distinguish between genetic and cultural evolution
D.3.10 Discuss the relative importance of genetic and cultural evolution in the recent evolution of humans
About this resource
This resource was first published in ‘Evolution’.