Option D — Evolution
D1. (a)
(b)




It appears that the number of Poseidonamicus increased because there is less
fossil evidence available from earlier periods;
The number of Poseidonamicus increased because of more ecological niches
available at lower sea temperature / species spreading over greater depth/they
evolved so more species/more time for adaptive radiation (speciation);
It appears that the number of Poseidonamicus increased because modern
classification methods recognize more species than previous methods;
It appears that the number of Poseidonamicus increased because more research
done at greater depths; [2 max]
(c)
1. The hypothesis is supported by data because the valve length increases over time
while average sea temperature decreases / there is an inverse/negative correlation
between shell size and sea temperature;
2. The hypothesis is supported by data because data suggests that evolution of new
species occurs more under lower temperatures. for example, evolution of a new
species was slow up to approx. 5 million years ago when sea temperature was
highest and evolution of new species was faster in last 5 million years when sea
temperature was lower;
3. The is not enough data to support hypothesis because the depth of habitat was not
assessed for extinct species;
4. The conclusions are unreliable because of lack of data from earlier time periods /
conclusions are unreliable because temperature relatively constant between 30
and 10 million years ago but the range of valves varies by about 100 μm; [3 max]
D2. (a)
1.
2.
3.
4.
non-living synthesis of simple organic molecules;
assembly of (simple organic) molecules into polymers;
origin of self-replicating molecules that made inheritance possible;
packaging of molecules into membranes with an internal chemistry different
from their surroundings; [1 max]
(b)
1. The initial atmosphere contained no free oxygen and anaerobic bacteria were the
first organisms on Earth;
2. some prokaryotes evolved to be were chloroplast-like /
photosynthetic/cyanobacteria;
3. Oxygen is by-product of the photosynthesis is produced by photolysis of water
(separation water using light energy) during the process of light dependent
reaction of photosynthesis/ [2 max]
(c)
1. Organic compounds/ molecules could have evolved in water as organic reactions are
aqueous;
2. Organic compounds/ molecules could have evolved in warm conditions/pools near
geothermal vents/volcanic pools, because warm conditions allow high reaction
rates;
3. Organic compounds/ molecules could have evolved in small pools where evaporation
was high because evaporation of water allows organic (precursor) molecules
to
become more concentrated;
4. O Organic compounds/ molecules probably did not evolve high temperatures not
desirable as organic molecules become
unstable;
5. Organic molecules could have polymerized on clay minerals/metal ions because clay
minerals/metal ions may act as catalysts / clay forms a
matrix for monomers to
attach;
2 max
D.3.
a.
1. The theory states that eukaryotes cells evolved from prokaryotes cells;
2. This theory explains how the organelles in eukaryotes, mitochondria/chloroplasts evolved
from (independent) prokaryotic cells;
3. Prokaryotic cells with similar features to mitochondria/chloroplasts were taken in by
larger heterotrophic prokaryote cell by endocytosis;
4. This theory is supported by characteristics of chloroplasts/mitochondria that are similar to
prokaryotes;
5. mitochondria/chloroplasts have naked DNA similar to prokaryotes;
6. mitochondria/chloroplasts divide/carry out fission similar to prokaryotes;
7. mitochondria/chloroplasts have 70S ribosomes / synthezise own proteins similar to
prokaryotes;
8. mitochondria/chloroplasts have double membranes similar to prokaryotes;
9. The cristae similar to mesosomes / thylakoid have similar structures in prokaryotes;
10. There are some problems with the theory for example the theory cannot be falsified as it
predicts something occurring in the past;
11. There are some problems with the theory for example the theory does not explain the
origins of cilia/flagella/linear chromosomes/meiosis;
12. There is some weaker evidence that cilia/flagella evolved from attached
bacteria/spirochetes;
6 max
b
1. self-replicating and catalytic activities of RNA;
2. short sequences of RNA have been able to duplicate/copy other RNA
molecules
accurately;
3. RNA enzyme/ribozyme (able to synthesize other molecules);
4. 3-dimensional structure of ribosome catalytic sites (for peptide formation)
are composed of
RNA;
5.
able to store information in sequence of (4) nucleotides (similar to DNA);
2 max
c.
1. The Miller-Urey Experiment simulated conditions of pre-biotic earth (in closed
container) to test the idea that organic molecules could have originated in early
earth’s environment ;
2. This container contained a mixture of water vapour, ammonia, methane,
hydrogen / reducing atmosphere;
3. This mixture was ignited with sparks/electric (discharge to simulate lightning);
4. The gas was cooled in a condenser / cooling of mixture and a liquid was
obtained;
5. In this liquid there were amino acids. The results from this experiment suggests
that simple organic molecules could have formed in the prebiotic conditions on
Earth.
H1.
(a) 625 % (percentage required) (accept answers in the range of 600 % to 650 %) [1]
(b)
(i)
a. pH rises in Hyde Park and falls along Oxford Street;
b. back to pre-walk level in six hours in Hype Park but not along Oxford Street;
[2]
(ii)
a.
b.
c.
d.
e.
(iii)


asthma (attack) constricts bronchioles (while walking);
exercise/walking increases cell respiration producing more CO2;
lower ventilation causes CO2 build-up thus lower pH;
CO2/pollutants in the air could be causing/triggering acidification;
inflammation (by-products) lower pH; [2 max]
This hypothesis is support by the data because bronchioles constriction is
demonstrated by the lower pH of the participants on oxford street;
This hypothesis is support by the data because oxford street participants has
higher inflammation measured by higher amounts of myeloperoxidase;
[1 max]
(c) allergens / dust mites / pollen / cold (temperature) / viral illness / exercise /
anxiety/stress [1] Award [1] for any two causes.
(b) (i) Award [1] for two correct glands.
a. salivary glands;
b. gastric glands;
c. pancreas;
d. wall of the small intestine; [2 max]
(ii)
a. pepsinogen converted to pepsin by stomach acidity/low pH/HCl;
b. trypsinogen converted to trypsin by enteropeptidase/enterokinase in small
intestine; [2]
H3.
(circulation of blood through liver tissues – accept properly annotated diagram)
a. hepatic artery brings oxygenated blood from the heart;
b. hepatic portal vein brings nutrients from small intestine;
c. Hepatic portal veins divide into smaller vessels that merge to form sinusoids
where liver cells/hepatocytes store and regulate nutrients;
d. Deoxygenated and low nutrient blood leaves through hepatic vein;
e. hepatocytes regulate blood sugar level by storing glucose as glycogen /
releasing glucose from breakdown of glycogen (facilitated by arrival from
portal vein);
f. Hepatocytes under influence of insulin will regulate blood sugar level by
storing glucose as glycogen and under influence of glucagon release glucose
from the breakdown of glycogen ;
g. blood lipids/cholesterol synthesized/broken down if required / secreted
through bile;
h. iron stored from breakdown of hemoglobin/released when Po2 is low;