BIOLOGY 1.5 Marks Questions

1. Occurrence of branched chain lipids in their cell membrane that reduce fluidity of cell membranes.
2. Having minimum amount of free water in their bodies. Removal of water provides resistance to high temperature.

1. Rhizobium in the roots (nodules) of legumes.
2. Mycorrhiza/Glomus with the roots of higher plants.

1. Parasitism.
2. Mutualism.
3. Commensalism.
4. Brood parasitism.

• Keeps prey population under control.
• Biological control methods.
• Maintains species diversity.
• Reduces intensity of competition among prey species.

1. Brood parasitism.
2. Commensalism.
3. Parasitism.
4. Mutualism.

J-shaped growth curve: The population grows exponentially, and after attaining the peak value the population abruptly crash, Due to environmental resistance/environment is ever changing/food and space are limited/end of season.

Whereas replacement level (RL) is the number of children a couple must produce to replace themselves in a population.

1. Mutualism between a flower and its pollinator follows co-evolution as the interaction should be safe from "cheating". A Fig species is pollinated by a particular species of wasp. While the wasp uses the fruit for oviposition and source of nourishment for its larvae, the fig is pollinated by the wasp.
2. Since both the participants in the mutualism are linked, a change, anthropogenic or otherwise, affecting one species will consequently also reduce the population of the other species. Plant-Pollinator interaction is an example of the same. Extinction of the pollinator will reduce the diversity of plant species which is dependent on it. Reduction in bees population is posing a threat to the diversity of crops.

1. Certain insect species and frogs have camouflage (cryptic colouration) to avoid detection by their predators
2. Some animals are highly distasteful to their predators, e.g. monarch butterfly accumulates a chemical by feeding on a poisonous weed during its caterpillar stage.
3. Some prey are poisonous and hence are avoided by predators.
4. Plants have developed thorns and spines as defence mechanism against browsing animals.
5. Some plants produce certain chemicals which affect the metabolism of the herbivores.

1. Numbers/ volume.
2. Coverage/ area.
3. Biomass/ area.
4. Numbers/ area.
5. Weight/ area.

1. Organisms.
2. Populations.
3. Communities.
4. Biomes.

1. Birthrates.
2. Death rates.
3. Sex ratio.
4. Age distribution.

1. Loss of unnecessary sense organs.
2. Presence of hooks/ adhesive organs and suckers.
3. Loss of digestive system.
4. High reproductive capacity

1. Burrowing Sandy.
2. Building cubes Muddy.
3. Holdfasts/ peduncle Rocky.

1. Plants have seeds and other vegetative propagules that remain dormant and tide over the unfavourable conditions.
2. Plants shed all their leaves during severe winter.

• Shark is eurythermal because it can tolerate and thrive in a wide range of temperatures.
• Polar bear is stenothermal as it can tolerate and thrive only in a narrow range of temperatures.
• The thermal tolerance determines the geographical distribution of organisms; hence shark can live in a wide variety of places but the polar bear is restricted only to a narrow range (polar regions or ice-capped mountains), beyond which it cannot survive.

• Desert lizards cope with the temperature variations in their habitat by behavioural means.
• They bask in the sun and absorb heat when their body temperature drops below the comfort zone.
• They move into the shade when the temperature starts increasing.

1. Population.
2. Community.
3. Ecosystem.
4. Biosphere.

1. It is capable of meeting all its water requirements through its internal oxidation of fat in which water is a by product.
2. It can concentrate its urine, so that only minimal volume of water is removed during excretion of wastes.

1. Escherichia coli.
2. Enterococcus faecalis.

1. The eggs of koel have evolved to resemble the eggs of host bird in colour and size, to reduce chances of the host bird detecting the foreign egg and throwing them out.
2. This type of interaction is called brood parasitism.

1. Loss of unnecessary sense organs.
2. Presence of adhesive organs like hooks and suckers.
3. Loss of digestive system.
4. Mechanism to counteract and neutralise the digestive juices.

1. Niche of an organism represents the defined range of conditions that it can tolerate, the diversity in the resources it utilises and the distinct functional role it plays in the ecological system.
2. The green plants/ algae are not found in very deep waters, as they need light for photosynthesis, they are the producers of the ecosystem.

• Heliophytes also called sun-loving plants, are those that require for their optimum growth full exposure to the sun. E.g., Mango.
• Sciophytes also called shade-loving plants, are those plants that require reduced light intensity. E.g., Lycopodium.

1. Represents Pre-reproductive age group.
2. Represents Reproductive age group.
3. Represents Post-reproductive age group.

2. Expanding population.

1. 'r' is intrinsic rate of natural increase.
2. With increase in 'r' the population size increases while a decrease in 'r' decreases the ponulation size.

1. Curve 'a'
2. It is not realistic as resources become limiting sooner or later.

• During summer, when the outside temperature is higher than our body temperature, we sweat profusely.
• The evaporation of sweat causes a cooling to maintain the body temperature.

1. Increasing RBCs production.
2. Decreasing binding capacity of haemoglobin.
3. Increased breathing rate.

1. They keep prey population under control.
2. Predators also help in maintaining species diversity in a community by reducing the intensity of competition among competing prey species.

1. They have short ears and short limbs (Allen's rule).
2. Seals have a thick layer of fat, called blubber under their skin, which acts as an insulator and reduces loss of body heat.

1. Interspecific competition.
2. Intraspecific competition.

The intraspecific competition is more intense because the requirement of the individual of the species are similar.

1. They can shorten the life cycle of the host and can weaken it.
2. They can drastically reduce the reproduction to the extent of causing sterility.
3. They reduce its population density.

1. Submerged.
2. Rooted emergent.
3. Rooted with floating leave.
4. free-floating.
5. Rooted Submerged.

1. At high altitude places, one may experience altitude sickness, as the atmospheric pressure is low and the body does not get enough oxygen.
2. But gradually the body gets acclimatised by increasing the red blood cell production, increasing the breathing rate and deffeasing the binding affinity of haemoglobin.

1. Hydrophyte.
2. Xerophyte.
3. Halophyte.
4. Mesophyte.

1. The Monarch butterfly is highly distasteful to its predators because of a special chemical present in its body.
2. The butterfly acquires this chemical by feeding ona poisonous weed during its caterpillar stage.

1. It is a case of mutualism because both the fig tree and the Wasp are benefitted by this interaction.
2. The female wasp uses the ovary of the flower as a site for oviposition and the developing seeds within the fruit for nourishing the larvae.
3. The fig inflorescence is pollinated when the wasp is searching for a suitable place for egg-laying.