Paper 2 Errors

What dies the iris do?

Change the size of pupil through muscle contractions

Quadrats- what must alway sbe done in a 6 marker

Compare data

Environmental factors

Avoid Co2

Soil pH

Temperature

Water availability

Sexual Reproduction

Many offspring so higher probability of survival

Colonise new areas by seed dispersal

Geotropism

Control- Gravity acts evenly on all sides

Decomposition- Bacteria and organic matter in ocean kills fish- WHY?

Bacteria decays organic matter

By digestion

Bacteria respire using oxygen

Lowers oxygen concentration in water

Reduced energy supply causes death of fish

Evolution-2 new species how?

• Isolation of species

• Habitat variation

• Genetic variation/mutation in each population

• Better adapted to survive and reproduce and pass on favourable alleles to offspring

• Eventually, cannot produce fertile offspring with each population

Explain why temperature of brain decreased when cold water drunk?

Blood cooled at mouth

blood flows to mouth

How do algae get energy?

photosynthesis using light absorbed by chlorophyll/chloroplasts to produce glucose

Give evidence that beak depth is an inherited characteristic

Give evidence that more than one gene controls beak depth

Offspring have similar beak depths to their parents

parents of a given beak depth produce offspring with several beak depths

Why range of beak depths is different?

Think competition

colonisers of Isabela have a range of beak depths due to different combinations of alleles of several genes

or due to different alleles of one gene

or due to mutation large range of (sizes / species of) seeds / food (on Isabela)

or large(r) seeds (on Isabela)

more competition for seeds / food (on Isabela) birds with larger beaks get enough food to (survive and) reproduce (on Isabela)

(survivors) pass on (beneficial) alleles to offspring

4 benefits of understanding human genome

diagnosis of inherited / genetic disorder

• gene therapy or treatment of inherited disorders

understanding ancestry

• tracing human migration patterns

How phototropism helps plant survive?

leaves / plant receive(s) / absorb(s) more light (so) more photosynthesis (so plant) produces more glucose

How eye adjusts to form a clear image of nearer object?

ciliary muscles contract

(so ciliary muscles have a) smaller diameter

(so) suspensory ligaments loosen / slacken

(so) lens thickens or lens becomes more curved / rounded

(thicker) lens is more convergent

light rays / image focused on retina

How lens corrects long sightedness

Convex / converging lens

light rays bent / refracted (inwards)

more light rays focused on retina

Why severa; groups of cells scraped off?

Why hormones added

Why nurtients

why at 20 degrees

so many plants produced

so differentiation occurs

Provide energy for respiration

Good growth

Why culture technique only one colour plant produced?

(all new plants have been) produced by asexual reproduction / mitosis or produced without (fusion of) gametes (so) all are genetically identical / clones

Why kidney transplant better than dialysis?

changes in concentrations / levels of substances / urea are minimised

(so) less / no chance of causing damage to body cells / tissues

not repeatedly puncturing skin or blood not in contact with machine

(so) less / no chance of infection or less / no chance of blood clots or no need to take anti-clotting drugs

To maintain high rate of reproduction in a culture?

Increase temperature

Add more protein

Add more oxygen

Adv if crops resistant to glyphosate?

can use the glyphosate / weed killer to kill weeds but not kill / affect crop

(so) less competition for light / water / minerals / ions

(so) crops have high(er) yield

Explain why a person with type 2 diabetes has higher blood insulin concentration than non diabetic

cells / liver / muscles absorb less glucose

(so) glucose concentration in blood remains high

(high blood glucose stimulates / causes) pancreas to release more insulin

Control variables for large investigations?

age

• height and mass

• proportion of males and females or group size

• (same) severity of diabetes • (same) activity (during investigation)

• (same) type of meal • dose of drug

• (similar) blood glucose concentrations at start

• other health conditions or other drugs being taken