- Two statements regarding evolution are made below.
I. Rates of evolution are typically very slow because
natural selection is usually _P selection.
II. The plant population growing on high-zinc-soil is able
to grow at concentrations which are otherwise lethal
to plants of the same species. This is Q
selection. P and Q refer to
(a) directional and disruptive selection respectively
(b) stabilising and directional selection respectively
(c) directional selection
(d) stabilising selection. (INBO 2017)
- Fish utilise oxygen dissolved in water. When the temperature
of water rises, it can pose physiological stress to the fish as
solubility of oxygen in water decreases. Which of the following
graphs correctly depicts the oxygen consumption rates of
resting fish and active fish under these conditions?
Note: Oxygen consumption by active fish is indicated by
solid line and by resting fish is indicated by dashed line.
(a)
Water temperature
Oxygen consumption
arbitrary units
10°C 40°C
(b)
Oxygen consumption
arbitrary units
10°C 40°C
Water temperature
(c)
Water temperature
Oxygen consumption
arbitrary units
10°C 40°C
(d)
Oxygen consumption
arbitrary units
10°C 40°C
Water temperature
(INBO 2016)
- An experiment to understand the relationship between
a herbivorous crab Mithrax forceps and the coral Oculina
arbuscula was undertaken in a shallow water coastal
ecosystem. Observation on predation of crab, growth
of algae, growth and mortality of corals were made. The
following graphs indicate the results obtained during the
experiment.
Predation of M. forceps with or without corals
After 1 hour
Crabs with access to corals Crabs without access to corals
After 24 hours
16
8
6
4
2
0
14
12
10
Number of crabs consumed
Algal growth
No crab Crab
25
15
5
20
10
Algal growth over coral (% of coral mass)^0
Coral growth
No crab Crab
14
8
4
2
12
6
Coral growth (% mass change per month)^0
Coral mortality
No crab Crab
80
20
30
40
50
60
70
10
0
Coral mortality (%)
A few statements based on the results obtained are made.
i. The presence of crabs has a negative influence on algal
growth and positive influence on coral growth.
ii. Presence of M. forceps is obligatory for the survival of
O. arbuscula.
iii. The coral species plays an important role in preventing
predation of M. forceps.
iv. The algae outcompete O. arbuscula in the absence of
M. Forceps.
Which of these statements are true?
(a) i, ii and iii only (b) i and iv only
(c) i, iii and iv only (d) iii and iv only
(INBO 2016)
- Animals belonging to the following groups are usually
hermaphrodites except
(a) gastropods (b) oligochaetes
(c) crustaceans (d) flatworms.
(NSEB 2015-16)
- Which of the following individuals will produce 16 types of
gametes?
(a) AaBbccDdeeFF (b) AaBbccDDEeFf
(c) AaBbCcddEEFF (d) AaBbCcDDEeFf
(NSEB 2015-16)
BIOLOGY
OLYMPIAD PROBLEMS