Evolution and biodiversity

Question 1

What are the observations of a population?

Answer 1

Individuals in a population vary in traits many of which are heritable.
Populations produce more offspring than can survive to produce offspring of their own - competition.
Species are generally suited to their environment.

Question 2

What is the mechanism of selection to drive change?

Answer 2

Individuals whose traits are best suited to survive a given environment will produce more offspring.
Accumulation of favourable inherited traits in populations over generations.

Question 3

What is the mechanism of evolution?

Answer 3

Founder individual reproduce and produce a range of offspring by genetic recombination and chance mutations.
Competition occurs and one genetic trait is favoured and survives, which is then inherited to the next generation.

Question 4

What is the evidence for evolution?

Answer 4

Palaentology
Biogeography
Comparative embryology and anatomy
Anatomical vestiges.
Biochemistry
Microevolution

Question 5

What is palaeontology?

Answer 5

Fossil records
Transitional fossils link two groups of organisms.

Question 6

What is biogeography?

Answer 6

On a large scale, continental drift, produces unique flora and fauna of Australasia.
Geographical isolation - marsupials vs placental mammals.

Question 7

What is biogeography on a small scale?

Answer 7

Different species in different geographical locations - barriers, e.g. oceans and mountains.
Mutation then selection, evolve to adapt to conditions.

Question 8

What is comparitive embryology and anatomy?

Answer 8

Similar features indicative of common ancestor.

Question 9

What are anatomical vestiges?

Answer 9

Features that no longer serve a purpose but have not devolved.
Whale pelvis, appendix, goosebumps.

Question 10

How is biochemistry evidence for evolution?

Answer 10

Common amino acids, RNA, DNA.
Can compare DNA sequences - the level of homology correlates with evolutionary distance.
Pseudogenes - non-functional but still exist.

Question 11

What is mircoevolution?

Answer 11

Evolution happening in action e.g.
Increased mosquito resistance to DTT
Antibiotic resistance - MRSA
Flu and COVID viruses.

Question 12

What is the burden of a dynamic genome?

Answer 12

Human evolution has been recent and rapid.
Therefore genetic disorders can arise.
It takes time for selection against these.
Modern medicine can help but stops evolving to defend against it.

Question 13

What is the mismatch hypothesis?

Answer 13

Metabolic disease occurs from lifestyle changing so quickly but genes staying the same e.g. excess calorie intake, less exercise, vitamin D deficiency.
Causes obesity, diabetes, atherosclerosis, hypertension.

Question 14

Why is biodiversity important?

Answer 14

Human health depends on the ecosystem - nutrition, natural medicines, can use other species for models in experiments.
But species can cause infectious diseases, and changes to the ecosystem from us are also a threat.

Question 15

What is a model organism?

Answer 15

Non-human species studied to understand biological phenomena and provide insight into working of organims.
In vivo models of animals are used because they have short lives so can be manipulated, are cheap, and have simple living requirements.

Question 16

What are the limitations of model organisms?

Answer 16

Organisms are not identical to humans so care is taken when extrapolating between species.
Ethical issues - tight regulation - Replacement, Reduction and Refinement.

Question 17

How are prokaryotes model organisms?

Answer 17

Most studied is E coli.
Easy and cheap to grow in a lab.
Host organism for the majority of recombinant DNA work.
But are significantly different from eukaryotes.

Question 18

How are simple eukaryotes model organisms?

Answer 18

Yeast, unicellular.
Smaller genome but share many characteristics with higher eukaryotes.
Cheap and easy to grow.
Used for the eukaryotic cell cycle.

Question 19

How are invertebrates model organisms?

Answer 19

Fruit fly, easily grown, rapid generations, few chromosomes, easily induced and observable mutations.
Nematodes as well.

Question 20

How are vertebrates model organisms?

Answer 20

Zebrafish, nearly transparent during early development.
Easy genetic manipulation, small, produce a large number of offspring.
Used in cardiovascular research as can regenerate damaged parts of heart.

Question 21

How are amphibians model organisms?

Answer 21

Eggs and embryos used in developmental and cell biology, toxicology and neuroscience.
Produces large embryos that are easy to manipulate.

Question 22

How are mammals model organisms?

Answer 22

Mouse - small so easy to keep, mutations cause a similar phenotype to humans.
Rats used as a toxological and neurological model due to large size of organs relative to mice.

Question 23

How are non-human primates model organisms?

Answer 23

Chimpanzees have strong similarities in physiology, behaviour, immunology and genetics.
Used in development of vaccines, e.g. TB and hepatitis.