Topic 4,5

Question 1

Describe natural selection of antibiotics resistance

Answer 1

resistance strands (variation) in population, caused by mutation
selective pressure (antibiotics)
survive and reproduce with binary fission
increase allele frequency of resistance strands
horizontal transfer of genes in plasmid

Question 2

Carbon cycle involves sinks (carbon is stored) and fluxes (carbon is transferred). What are the largest sink and flux?

Answer 2

Sink: oceans
Flux: photosynthesis

Question 3

What are the most significant greenhouse gases? what are other greenhouse gases?

Answer 3

Most significant: carbon dioxide, water vapour

methane, nitrogen oxides (high temp inside car engines)

Question 4

What does the impact of the greenhouse gas depend on?

Answer 4

ability to absorb long-wave radiation (especially infrared): methane has 33 times the effect of CO2
abundance in atmosphere: CO2 is abundant and persistent in atmosphere

Question 5

How does the Greenhouse Effect work?

Answer 5

1. Solar radiation emitted by the sun penetrates the atmosphere and reaches the Earth’s surface
2. Some solar radiation is reflected by the atmosphere and Earth’s surface
3. Earth surface absorbs shot-wave solar energy and emits longer wavelength radiation (infrared)
4. Most infrared radiation is absorbed by greenhouse gases that retain heat in the atmosphere
5. Some of the infrared radiation passes through the atmosphere

Question 6

What causes threats to coral reefs?

Answer 6

Increased concentrations of dissolved carbon dioxide.
carbonic acid, bicarbonate, carbonate
ocean acidification

Question 7

Convergent evolution

Answer 7

different species independently evolve structures to serve a common function. The similarities are because of similar selective pressures in the environment. e.g. whale and fish

Question 8

Adaptive radiation

Answer 8

closely related organisms perform different functions, therefore have different structures e.g. the pentadactyl limbs

Question 9

Define evolution

Answer 9

The cumulative change in the heritable characteristics of a population

Question 10

What are the five evidence for evolution

Answer 10

Fossil record
selective breeding
evolution of homologous structures by adaptive radiation
speciation
continuous variation

Question 11

Define species

Answer 11

A group of individuals that can interbreed to produce viable, fertile offsprings

Question 12

Contrast analogous structures and homologous structures.

Answer 12

Homologous structures are structures that are similar in organisms because they were inherited from a common ancestor, but perform a different function, via adaptive radiation. e.g. pentadactyl limbs

Analogous structures are structures that are similar but were not inherited from a common ancestor, the organisms independently evolved the characteristic (via convergent evolution). e.g. whale and fish