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Organisms And Population Mcq
Quiz 3
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Q.1
Which of the following is true with reference to temperature diffrence ?
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a) 1. Terrestrial Habital > Aquatic Habitat 2. Sea < Deep fresh water lakes
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b) 1. Aquatic Habitat > Terrestrial Habitat 2. Sea < Deep fresh water lake
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c) 1. Terrestrial Habital = Aquatic Habitat 2. Sea < Deep fresh water lake
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d) 1. Terrestrial Habital < Aquatic Habital 2. Sea = Deep fresh water lake
Explanation
Answer:(a)
Q.2
Which is appropriate option if we take ‘T’ for correct statement and’F’ for wrong statement ? (i) Energy pyramids are always upright. (ii) Detritus food chain begins with dead organic matter (iii) C4 path is the only path seen in xerophytes (iv) Biodiversity is less in equatorial region because of more sunlight (v) At normal Temperature daphnis lays parthenogenetic eggs. which develops into male(♂)
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a) T F T T F
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b) T T F F F
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c) F F F T F
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d) T F T F F
Explanation
The pyramid of energy is always upright because when the energy flows from one trophic level to another, some energy is always lost as heat in each step. (i) is true. Detritus food chain is the type of food chain that starts with dead organic materials. The dead organic substances are decomposed by microorganisms. (ii) is true. Many succulent xerophytes employ the Crassulacean acid metabolism or better known as CAM photosynthesis. (iii) is false. Species diversity is higher at the equator than at the poles. There might be more biodiversity near the equator because it's warmer year round, allowing organisms to continue growing.(iv) is false. A female produces a clutch of parthenogenetic (amictic) eggs. During the parthenogenetic cycle, females produce diploid eggs that develop directly into daughters. (v) is false. Answer:(b)
Q.3
In the section of lichen which layer is seen just below “ upper cortex”
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a) Medulla
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b) Algal layer
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c) lower cortex
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d) All of these
Explanation
The basic structure of crustose lichens consists of a cortex layer, an algal layer, and a medulla. The upper cortex layer is differentiated and is usually pigmented. The algal layer lies beneath the cortex. The medulla fastens the lichen to the substrate and is made up of fungal hyphae. Answer:(d)
Q.4
Give correct option for the given true and false statements (i) Some insects, birds and mammals living in warm and dry climate have more darker black pigments than the races of same species living in cold and humid climate. (ii) Temperature variation is much lesser in aquatic habitat compared to terrestrial habitat (iii) In deep fresh water lakes, there is gradual increase in temperature from surface to the bottom (iv) In an aquatic habitat production increases with increasing depth. (T =True, F = False)
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a) F F F F
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b) T F T F
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c) T T F T
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d) F T F T
Explanation
In warm humid climates many animals like insects, birds and mammals bear darker pigmentation than the races of some species found in cool and dry climates. This phenomenon is known as Gioger rule. (i) is false. In deep fresh water lakes, there is gradual decrease in temperature from surface to the bottom. (iii) is false. Deeper water generally results in lower light intensity and higher water pressure but greater stability of other factors in the aquatic environment, e.g. temperature and sediment characteristics. (iv) is true. Answer:(d)
Q.5
What is correct for the given statement ? Statement X : Ascaris are permanent parasites Statement Y : Ascaris lives inside the host’s body
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a) Both X&Y are correct
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b) Both x & Y are wrong
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c) X is wrong Y is true
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d) X is correct & Y is true
Explanation
Ascaris lumbricoides remains the most common endoparasite in humans. In ideal settings, Ascaris ova can persist for over 14 years. Therefore, this parasite flourishes in tropical areas where year-round transmission is possible. Both statement are true. Answer:(a)
Q.6
What is true for the members of same species [CBSC, PMT - 2002]
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a) Capacity of inter breeding
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b) shows same ecological niche
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c) show different type of ecological niche
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d) They have different Habitat
Explanation
Species may be defined as the uniform interbreeding population of individuals which freely interbreed among themselves. Answer:(a)
Q.7
Which of the following is incorrect if ‘O’ sign is used for beneficial and ‘+’ sign for harmful ?
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a) Penicillium ↔ Gram +ve bacteria ; Penicillium: ‘+’
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b) Rhizobium ↔ palnt - leguminosae family : Both ‘O’
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c) Tiger ↔ Rabbit ; Tiger : ‘O’
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d) Shank fish ↔ Suckerfish ; Suckerfish ; ‘O’
Explanation
Answer:(a)
Q.8
Consider the following two statements I. Red algae are red because of the presence of pigment phycoerythrin; this pigment reflects red light and absorbs blue light II. Because blue light penetrates water to grater depth than light of longer wavelengths, these pigments allow red algae to photosynthesize and live at somewhat greater depth than most other “algae:
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a) Both I and II are correct and II explains I
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b) Both I and II are correct but II does not explain I
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c) I is correct but II is incorrect
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d) I is incorrect but II is correct
Explanation
Red algae or Rhodophyta are mostly found in the freshwater lakes and are the oldest type of eukaryotic algae. They are red in colour due to the presence of a pigment called chlorophyll A, phycocyanin, and phycoerythrin. They also can survive at greater depths in the ocean than some other algae, because the phycoerythrin's absorption of blue light waves, which penetrate deeper than other light waves do, allows red algae to carry out photosynthesis at a greater depth. Both are correct and II explains I. Answer:(a)
Q.9
Darwinian fitness is represented by
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a) Low r value
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b) High r value
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c) High K value
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d) Low K value
Explanation
Population evolves to maximize their "r" value which results in more Darwinian fitness. Increase in "r" value means birth rate is more and death rate is less. Answer:(b)
Q.10
The country with the given population pyramid is likely to have
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a) Low birth rate
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b) High birth rate
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c) Declining Population in future
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d) More females than males
Explanation
Triangular age pyramid has high proportion of prereproductive individuals, moderate number of reproductive individuals and fewer post-reproductive individuals. It represents young or rapidly growing population. Answer:(b)
Q.11
Which one of the following is categorised as a parasite in true sense?
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a) Human foetus developing inside the uterus draws nourishment from the mother
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b) Head louse living on the human scalp as well as laying eggs on human hair
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c) The cuckoo (koel) lays its eggs in crow’s nest
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d) The female Anopheles bites and sucks blood from humans
Explanation
A parasite is an organism that lives on or in a host organism and gets its food from or at the expense of its host. The human foetus depends during its development phase not entire life. Thus it cannot be considered as parasite. Head louse (Pediculus humanus capitis) is an obligate parasite. Female anopheles is vector and is not a parasite because they do not bite the human. Cuckoo are brood parasites as they depend on other for their young ones to develop. They are not a true parasite. Answer:(b)
Q.12
The population of an insect species shows an explosive increase in number during rainy season followed by its disappearance at the end of the season. What does this show?
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a) S-shaped or sigmoid growth of this insect
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b) The food plants mature and die at the end of the rainy season
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c) Its population grows curve is of J-type
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d) The population of its predators increases enormously
Explanation
Any species growing exponentially under unlimited resource conditions can reach enormous population densities in a short time. Such population shows J growth curve also known as exponential curve. Same scenario is seen inthis question. Population curve of insect is J curve. Answer:(c)
Q.13
Which of the following animals are osmoconformers?
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a) Hagfishes
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b) Sharks
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c) Rays
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d) All the above
Explanation
Osmoconformers are marine organisms that maintain an internal environment which is isotonic to their external environment. This means that the osmotic pressure of the organism's cells is equal to the osmotic pressure of their surrounding environment. Most osmoconformers are marine invertebrates such as echinoderms (such as starfish), mussels, marine crabs, lobsters, jellyfish, ascidians (sea squirts - primitive chordates), and scallops. There are a couple of examples of osmoconformers that are craniates such as hagfish, skates and sharks. Answer:(d)
Q.14
Bacteria, fungi, lower plants survive in adverse conditions by
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a) diapause
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b) suspended growth
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c) migration
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d) formation of thick walled spores
Explanation
Spores are the reproductive units similar to that of seeds which are characterized as thick-walled and highly resistant to Harsh conditions. Bacteria, fungi and lower plants survive in adverse conditions through formation of thick walled spores. Bacteria form endospores which is probably the most resistant living thing known. They may remain alive in boiling water for more than 2 hours. Answer:(d)
Q.15
Biotic factors are:
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a) chemical factors of soil which affect life
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b) physical factors of soil which affect life
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c) all living organisms which influence other organisms
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d) factors of atmosphere which affect life
Explanation
A biotic factor could be defined as 'the influence upon the environment of organisms owing to the presence and activities of other organisms. Biotic factors include animals, plants, fungi, bacteria, and protists. Answer:(c)
Q.16
A population growing in a habitat with limited resources shows phase of growth in the following sequence:
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a) Acceleration → Deceleration → Lag phase → Asymptote.
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b) Lag phase → Acceleration → Log phase → Deceleration.
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c) Lag phase → Acceleration → Deceleration → Asymptote.
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d) Acceleration → Log phase → Crash phase.
Explanation
A population growing in a habitat with limited resources show initially a lag phase, followed by phases of acceleration and deceleration and finally an asymptote, when the population density reaches the carrying capacity. Answer:(c)
Q.17
Assertion: Bell shaped age pyramids represents a stable population. Reason: Proportion of individuals in reproductive age group is higher than the individuals in the pre – reproductive age group.
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a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
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b) Both Assertion and Reason are true but Reason is NOT the correct explanation of Assertion.
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c) Assertion is true but Reason is false.
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d) Both Assertion and Reason are false.
Explanation
Age pyramid of stable population looks like a bell. Assertion is true. In a bell-shaped age pyramid, the number of prereproductive and reproductive individuals is almost equal. Postreproductive individuals are comparatively fewer. Reason is false. Answer:(c)
Q.18
(i) Mango tress cannot grow in temperate countries like Canada and Germany. (ii) Tuna fish are rarely caught beyond tropical latitudes in the ocean. (iii) Snow leopards are not found in Kerala. Which of the following factor is responsible for the above observation?
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a) Light.
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b) Water.
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c) Temperature.
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d) Soil.
Explanation
All the above example prove significance of temperature. Temperature is the most important ecologically relevant environmental factor. The levels of thermal tolerance of different species determine to a large extent their geographical distribution. Answer:(c)
Q.19
The best explanation for the change in the distribution of Chathamalus observed 33 months after removal of the larger Balanus individuals is that :
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a) Balanus feeds on Chathamalus larvae
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b) Balanus does not reproduce as quickly as Chathamalus.
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c) Balanus has less tolerance for wet conditions.
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d) Balanus adults are mobile.
Explanation
A species whose distribution is restricted to a small geographical area because of the presence of a competitively superior species, is found to expand its distributional range dramatically when the competing species is experimentally removed. Connell’s elegant field experiments showed that on the rocky sea coasts of Scotland, the larger and competitively superior barnacle Balanus dominates the intertidal area, and excludes the smaller barnacle Chathamalus from that zone. Once Balanus is removed, Cathamalus population and distribution changes. Answer:(a)
Q.20
Crustacian Astacus = Green gland Marine turtle = X what is ‘X’ accroding to the information given ?
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a) Salt gland
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b) Kidney
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c) chlorine secretory cells
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d) None of these
Explanation
They function as osmoregulatory organs For Marine turtle kidney is the primary organ of osmoregulation Answer:(b)
Q.21
In a population of frog ‘J’ type of population growth curve is seen than which information from the given graph can be true for “ point A” (i) Vital Index < 100 (ii) Birth rate < death rate (iii) Birht rate > death rate
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a) I
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b) II, III
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c) I, III
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d) I, II
Explanation
At point A, direction of curve is downward. This implies that death rate is greater than birth rate. The vital index is the ratio between natality or number of births and mortality or the number of deaths in a given time duration. The formula of vital index is Natality/Mortality x 100. Since mortality is greater than natality, vital index will be less than 100. Answer:(d)
Q.22
Which path is followed by plants as a part of adaptation in an ecosystem where Kangaroo rat is living ?
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a) C3 Path
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b) C4 Path
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c) CAM Path
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d) TCA Path
Explanation
kangaroo rat are found in North American deserts. Desert plants have a thick cuticle on their leaf surfaces and have their stomata arranged in deep pits (sunken) to minimise water loss through transpiration. They also have a special photosynthetic pathway (CAM) that enables their stomata to remain closed during day time. Answer:(c)
Q.23
From the given option find out the correct pair ?
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a) Mesofauna - Earthworm
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b) Macrofauna - spider
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c) Microfauna - fungi
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d) None of these
Explanation
Soil mesofauna are invertebrates between 0.1mm and 2mm in size, which live in the soil or in a leaf litter layer on the soil surface. Nematodes, mites, springtails, proturans, and pauropods are typical members of the mesofauna. Macrofauna, in soil science, animals that are one centimetre or more long but smaller than an earthworm. Potworms, myriapods, centipedes, millipedes, slugs, spiders are examples of macrofauna. Microfauna are the smallest of the soil fauna and are less than 0.1 mm in size, and so need a microscope to be seen. Answer:(b)
Q.24
Recently a village was badly affected by jaundice and Dengue,which of the following will decrease due to this ?
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a) No. of persons
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b) area
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c) Birthrate
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d) Death rate
Explanation
Jaundice and dengue is a serious condition. If the severity is not noticed and if it is not treated on time and lead to decrease in number of people i.e., death. Answer:(a)
Q.25
The turtle of Galapagus island and the goats living there both were eating tender grass, state the relationship.
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a) Interspecific competition
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b) Emigration
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c) predation
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d) None of these
Explanation
When resources are limited the competitively superior species will eventually eliminate the other species, but evidence for such competitive exclusion occurring in nature is not always conclusive. The Abingdon tortoise in Galapagos Islands became extinct within a decade after goats were introduced on the island, apparently due to the greater browsing efficiency of the goats. Answer:(a)
Q.26
Many freshwater animals cannot live for long in sea water and vice versa because of
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a) Buoyancy related problem
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b) Lack of impermeable skins
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c) Thermolabile enzymes
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d) Osmotic consideration
Explanation
Many freshwater animals cannot live for long in sea water and vice versa because of the osmotic problems, they would face. Answer:(d)
Q.27
In a field experiment, when all Pisaster starfish were removed from an enclosed intertidal area, the result was
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a) Increase in diversity of invertebrates
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b) Extinction of many invertebrate species
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c) Inability of Pisaster to enter the area again
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d) Replacement of Pisaster by other starfish
Explanation
In the rocky intertidal communities of the American Pacific Coast the starfish Pisaster is an important predator. In a field experiment, when all the starfish were removed from an enclosed intertidal area, more than 10 species of invertebrates became extinct within a year, because of interspecific competition. Answer:(b)
Q.28
Very small animals are rarely found in polar region mainly because
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a) Smaller animals have a relatively slower heart rate
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b) Smaller animals have more surface area relative to their volume
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c) Smaller animals are invariably herbivores
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d) Smaller animals rely on diffusion for exchange of gases with the environment
Explanation
Heat loss or heat gain is a function of surface area. Since small animals have a larger surface area relative to their volume, they tend to lose body heat very fast when it is cold outside; then they have to expend much energy to generate body heat through metabolism. This is the main reason why very small animals are rarely found in polar regions. Answer:(b)
Q.29
A population interaction where one species is harmed whereas the other is unaffected is called as
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a) Mutualism
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b) Competition
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c) Predation
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d) Amensalism
Explanation
Species A
Species B
Name of interaction
+
+
Mutualism
-
-
Competition
+
-
Predation
+
-
Parasitism
+
0
Commensalism
-
0
Amensalism
Interspecific interactions arise from the interaction of populations of two different species. They could be beneficial, detrimental or neutral (neither harm nor benefit) to one of the species or both. Assigning a ‘+’ sign for beneficial interaction, ‘-’ sign for detrimental and 0 for neutral interaction. Answer:(d)
Q.30
Intraspecific competition is strongest when the
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a) Species overlap in their distribution
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b) Populations overlap in their ranges
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c) Population is at its carrying capacity
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d) Reproductive rate is at its maximum
Explanation
Competition present between the members of the same species compete for limited resources is called Intraspecific competitions. Maximum number of individuals of a population which can be supported with optimum resources for their survival is called carrying capacity. when resources are limited, competition is maximum. Answer:(c)
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