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CBSE Questions for Class 12 Medical Biology Ecosystem Quiz 7 - MCQExams.com
CBSE
Class 12 Medical Biology
Ecosystem
Quiz 7
An ecosystem which can be easily ruined/damaged but can recover after some time if damaging effect stops. The ecosystem is characterised by having
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Low and poor stability with low resilience
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High stability and low resilience
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Low stability and high resilience
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High stability and high resilience
Explanation
Stability is the power of a system to be in their state against the unfavourable condition. Resilience is the capability of regaining into its original shape or position after being deformed. Hence, the ecosystem has low stability and high resilience e.g., forest fire and then reforestation in that particular area.
Which one of the following class of animals constitutes the largest biomass on earth?
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Insects
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Fish
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Mammals
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Reptilians
Explanation
The class of insect contains the maximum number of species in the world. This is the class characterized by the presence of organisms with wings, antennae and joined appendages. These are the animals which constitute the largest biomass on the Earth.
Thus, the correct answer is option A.
Select the correct match :
I
II
i) Competition
a) Tapeworm and man
ii) Commensalism
b) Lichen
iii) Mutualism
c) Cattle egret and cattle
iv) Parasitism
d) Lions and Leopards
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i - d, ii - c, iii - b, iv - a
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i - d, ii - b, iii - c, iv - a
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i - c, ii - b, iii - d, iv - a
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i - a, ii - b, iii - d, iv - c
Explanation
There are five types of interaction between different organisms in an ecological communities. These are competition, commensalism, mutualism, parasitism and predation.
Competition is a type of interaction in which both the species are negatively affected. In this, the animals compete for the same food. For example, lions and leopards.
In commensalism, one species is benefited while other is neither harmed nor benefited. For example, cattle egret and cattle.
Mutualism is a type of interaction in which both the species are benefited. Lichen shows mutualistic interaction between fungus and algae.
Parasitism is a type of interaction in which one species is benefited while other is harmed. For example, tapeworm and man. In this, tapeworm is benefited and man is harmed.
Thus, the correct answer is option A.
Last stable community is succession which depends on climate is
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Seral community
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Climax community
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Poineer community
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None of the above
Explanation
The gradual change in the species structure of an ecological community is known as ecological succession. A climax community is the final community formed when the ecological succession becomes stable. It remains relatively unchanged until destroyed by an event such as fire or human interference. It is also known as a stable biological community.
So, the correct answer is option B.
Keystone species are
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Species belonging to same period
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Species that determine structure of biotic community
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Species reproducing sexually
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Species recorded only in the fossil state
Instead of excreting, these can store urea in the tissues
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Birds
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Fish
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Elephants
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Camels
Explanation
Camels known as the ship of the desert have a number of adaptation mechanisms that help them to survive successfully in dry and arid climates in which there is shortage of water and high environmental temperature. When water is not available, camels either excrete a highly concentrated urine or do not produce urine at all and store urea in tissues to avoid water loss.
So the correct option is D.
Keystone species deserve protection because these
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Are capable of surviving in harsh environmental conditions
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Indicates presence of certain minerals in the soil
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Have become rare due to the over-exploitation
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Play an important role in supporting other species
Explanation
Correct Option: D
Explanation:
Keystone species
are species that have a very low population but their impact on the ecosystem structure, composition, and functioning is disproportionately significant.
These play a very important role in
supporting other species and maintaining the ecosystem balance
hence deserve protection.
Examples of some keystone species are sea otters, beavers, etc.
Given below is one of the types of ecological pyramids
This type represents
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Pyramid of numbers in a grassland
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Pyramid of biomass in a fallow land
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Pyramid of biomass in a lake
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Energy pyramid in a spring
Explanation
Biomass is the amount of dried matter which is present in a particular area. Pyramid of biomass in a lake shows spindle-shaped pyramid. Pyramid of energy is always upright as only 10% energy is transferred from one trophic level to another. In this the biomass of the producer is minimum. The primary consumer has the highest biomass while the secondary consumer has lesser biomass than the primary consumer. Pyramid of the number in a grassland is also upright as the producers are always maximum in number than herbivores and carnivores.
So, the correct answer is option C.
In a lake ecosystem, pyramid of biomass is
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Upright
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Inverted
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Anything is possible
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None of the above
Explanation
An ecological pyramid of biomass shows the relationship between biomass and trophic level by quantifying the amount of biomass present at each trophic level of an ecological community at a particular moment in time. The .pyramid of biomass may be inverted. For example, in a lake ecosystem, the standing crop of phytoplankton, the major producers, at any given point will be lower than the mass of the heterotrophs, such as fish and insects. This is explained as the phytoplankton reproduce very quickly but have much shorter individual lives.
Succession is
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Orderly process of community change till stability
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Gradual, directional and continuous process
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Series of biotic communities that appear gradually in a barren area
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All of the above
Explanation
Ecological succession is the process of evolution of the biological community. It is a continuous, unidirectional sequential change in the species composition of a natural community. It is the orderly process of community change till its stability. The primary succession mainly takes place on the barren land which is followed by secondary succession. Secondary succession takes place on a previously colonized, but disturbed or damaged habitat.
So, the correct answer is option D.
Water requirement of Kangaroo/Desert rat is largely met by
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Hydration of food
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Metabolic water
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Hygroscopic skin
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Moist soil
Explanation
$$\textbf {Correct Option (B):} $$
$$\textbf {Solution:} $$
$$\textbf {Option (A):} $$
$$\bullet$$
$$\textbf {Option (B):} $$
$$\bullet$$ Metabolic water in Kangaroo and Desert rat is sufficient for fulfilling their water requirement.
$$\bullet$$ These animals consumes a lot of grains which ae mostly carbohydrate and fat rich. The carbohydrate are fats while breakdown using oxygen produces water as a byproduct.
$$\bullet$$ That amount of water is sufficient for these animals.
$$\bullet$$ 107-110grams of water can be produced via metabolism of 100 grams of fat.
$$\bullet$$ The water loss in their bodies is extremely minimal and hence they don't need to consume water separately in most cases.
$$\textbf {Option (C):} $$
$$\bullet$$
$$\textbf {Option (D):} $$
$$\bullet$$
Hence, the option(B) is the correct answer.
Formation of organic matter takes place by
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Chemical weathering
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Soil micro-organisms
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Herbivores
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Soil water
Climax community is
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First stable community
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Unstable
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Unstable that develops in the beginning of succession
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The last stable community
Explanation
Correct option: D
Explanation:
Ecological succession
is the process in which a bare area is converted into a forest or a water area transformed into a forest.
The conversion is always from
xeric to mesic form.
The first stable community is the
pioneer species
and that the final one is the
climax community.
All those stages between them are called
seral stages.
Hence, the c
limax community is "
t
he last stable community
."
Series of changes on previously barren area is
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Sere
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Climatic climax
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Primary succession
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Secondary seccession
Explanation
Succession is a series of progressive changes in the composition of an ecological community over time. In primary succession, there is a series of changes occuring on a previously barren area, for example, newly exposed or newly formed rock is colonized by living things for the first time.
In secondary succession, an area previously occupied by living things is disturbed—disrupted—then recolonized following the disturbance.
A seral community (sere) is an intermediate stage found in ecological succession in an ecosystem advancing towards its climax community.
Climatic climax is one of the ecological climaxes possible in a particular climatic area whose stability is directly due to the influence of climate.
As compared to seral communities, the number of niches in climax communities would be
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Same
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Fewer and generalised
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More and specialised
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None of the above
Explanation
Niche is nothing but the climatic surroundings of an organism. It is the role a species plays in its respective environment. When a climatic community reaches its end-stage in the process of ecological succession, it is called the climax community. The organisms of the climatic community have the most type of evolutionary trends. So, their niches are more in number. They are also specialized as their organisms show a steady stage of development.
So, option C is the correct answer.
A community, which starts succession in a habitat is
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Pioneer community
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Seral community
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Biotic community
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Ecosere
Explanation
the process of ecological succession means the change that occurs in an ecological community over a period of time. The community which starts the process of ecological succession is called the pioneer community. The intermediate community is the seral one.
So, option A is the correct answer.
What does the following sequence represent ?
Blue-Green Algae $$\rightarrow$$ Crustose Lichens $$\rightarrow$$ Foliose Lichens $$\rightarrow$$ Mosses $$\rightarrow$$ Shrubs $$\rightarrow$$
Dicotyledonous trees
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A food pyramid
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Ecological succession
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Genetic drift
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Phylogenetic trend
Explanation
Ecological succession is the process of evolution of a newly formed water body or a soil body into a forest land.
The mentioned process represents the evolution of a newly formed rock into a forest area. It involves the steps :
Blue -Green Algae
→
→
Crustose Lichens
→
→
Foliose Lichens
→
→
Mosses
→
→
Shrubs
→
Dicotyledonous trees
In ecological succession from pioneer to climax community, the biomass shall
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Decrease
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Increase and then decrease
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No relation
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Increase continuously
Explanation
When the community moved from a pioneer community to the climax community, the biomass will increase. This will increase the biomass because the number of organisms belonging to different species will also increase. Along with this, the number of organic matter collection will increase due to the accumulation of organic matter. So, the biomass will increase.
So, option D is the correct answer.
Keystone species is of
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Always dominant
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Useful in maintaining structure and function of biotic community
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With maximum biomass
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All the above
Explanation
$$\textbf {Correct Option (B):} $$
$$\textbf {Solution:} $$
$$\textbf {Option (A):} $$
$$\bullet$$
$$\textbf {Option (B):} $$
$$\bullet$$ It
is the species that play a vital role in maintaining the ecosystem balance.
$$\bullet$$
It either directly or indirectly affects all the species present in that ecosystem.
$$\bullet$$ Absence of this species can alter the ecosystem majorly.
$$\textbf {Option (C):} $$
$$\bullet$$
$$\textbf {Option (D):} $$
$$\bullet$$
Hence, the option(B) is the correct answer.
Succession in a 6 metre deep pond exhibits a sequence of :
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Submerged Plants $$\rightarrow $$Reeds $$\rightarrow$$Herbs $$\rightarrow$$Floating Plants $$\rightarrow$$ Shrubs $$\rightarrow$$Trees
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Floating Plants $$\rightarrow$$Submerged Plants $$\rightarrow$$ Reeds $$\rightarrow$$Herbs$$\rightarrow$$ Shrubs $$\rightarrow$$Trees
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Shrubs$$\rightarrow$$Trees$$\rightarrow$$submerged Plants $$\rightarrow$$ Floating Plants $$\rightarrow$$ Reeds $$\rightarrow$$ Herbs
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Submerged Plants $$ \rightarrow$$Floating Plants $$\rightarrow$$Reeds$$\rightarrow$$ Herbs$$\rightarrow$$Shrubs$$\rightarrow$$Trees.
Explanation
Development of biotic organisms in a newly formed pond or lake is called hydrosere or hydrarch.
It starts as soon as the muddy water becomes clear. The stages includes
1. Phytoplankton stage
2. Submerged root stage
3. Floating root stage
4. Reeds stage
5. Herbs stage
6. Woodland stage
7. Forest stage
Primary succession is development of communities on
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Newly exposed habitat
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Cleared forest area
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Freshly harvested crop field
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Pond filled after a dry season
Explanation
Correct option: A
Explanation:
Primary succession
is the development of forest areas in an area that has been bare for a long period of time.
The first community to inhabit the area is the
pioneer species.
The final community to be stable is the
climax community.
And the different stages that come between it are known as the
seral stages.
Hence, p
rimary succession is the development of communities in "
Newly exposed habitat
".
Plant succession occurring in a sandy area is
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Psammosere
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Halosere
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Xerosere
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Hydrosere
Explanation
Ecological succession seen in coastal areas with sandy rocks is called psammosere succession. They are the seral communities, seen primarily in an area.
So, option A is the correct answer.
Last stabilised community in a plant succession is known as
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Seral Community
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Pioneer Community
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Ecosere
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Climax Community
Explanation
The process of development of new communities is called the process of ecological succession In this type, several different communities are formed and they evolve and progress with the passage of time. It starts with the pioneer community, proceeds with seral community and finally comes into existence the climax community. It is the last and most stabilised community to live in that ecosystem till its destruction takes place.
So, option D is the correct answer.
In pond ecosystem, the shape of pyramid of number is?
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Linear
0%
Irregular
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Upright
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Inverted
Explanation
In the pond ecosystem, the shape of the pyramid of numbers is upright. In this, the number of producers are maximum, followed by primary consumers (herbivores), followed by secondary consumers (carnivores). The base of the pyramid of number represents the producers in a pond ecosystem.
Thus, the correct answer is option C.
Keystone species should be protected as they
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Are capable of certain minerals in the soil.
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Indicate presence of certain minerals in the soil.
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Have become rare due to over-exploitation.
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Play an important role in supporting other species.
Explanation
Keystone species are the ones that are present in less numbers and are non dominating species. Yet they play a very important role in maintaining the structure and balance of the ecosystem. So, they should be taken proper care off.
So, option D is the correct answer.
In succession, the structural complexity
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Drastically increases
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Remains constant
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Slowly increases
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Does not increases
Explanation
Int he process of ecological succession.. many different species invade a particular geographic location. The first community is the pioneer community, it is followed by many seral communities and the last one is the climax community. The individuals of climax community have the maximum adaptation to evolution and are most complex structurally.
So, option C is the correct answer.
Term used to describe non-dominant species that dictates community structure is
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Pioneer species
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Keystone species
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Transitional species
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All of the above
Explanation
Keystone species are the ones that live in a particular area and determine the flora and fauna and overall structure of the area. They might not be in great numbers but drastically affect the structure of the community.
Pioneer species are hardy species that are the first to colonize barren environments or previously biodiverse steady-state ecosystems that have been disrupted, such as by fire.
A transitional fossil may be defined as a fossil that exhibits traits common to both ancestral and derived groups.
So, option B is the correct answer.
Nature of climax community depends upon
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Water
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Temperature
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Soil fertility
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Climate
Explanation
Climax community is the one which is last to invade in the process of ecological succession. It is the most stabilised communities of all. It is the final stage of succession and is unchanged. Its nature depends on its climate. It has various adaptations to suit to its climatic conditions.
So, option D is the correct answer.
Deserts can be converted into green land by
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Tropical trees
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Oxylophytes
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Halophytes
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Psammophytes
Explanation
Desert plants are called psammophytes. They have the capacity to survive in desert climates and sand filled environment over there. So, these plants have the capability to grow in deserts and convert them into grasslands.
So, option D is the correct answer.
Which of the following is not a primary coloniser?
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Viruses
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Lichens
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Blue-green algae
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Mosses
Explanation
Viruses are said to be a link between living and non living. This is because they cant reproduce on their own. They need a host tor reproduce. Once they enter a living host, they start the process of reproduction.
So, option A is the correct answer.
A keystone species is the one which has
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A small proportion of total biomass but has a huge impact on the community's organisation and survival.
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A plenty of biomass but low impact on community's organisation.
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A rare species with little impact on biomass and other species in the community.
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A dominant species which has a large proportion of biomass and which affects many other species.
Explanation
A keystone species is a non dominant species. It determines the structure of a given population, despite of present in limited amounts.
So, option A is the correct answer
In autogenic succession,
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The community itself modifies its own environment thus causing its own replacement by a new community.
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Early dominance of heterotrophs.
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Replacement of existing communities due to external conditions.
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Early and continued dominance of autotrophic organisms.
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There is previously built substratum with already existing matter.
Explanation
Auto means self. Genic means to produce. In autogenic succession, the biotic that are present in the ecosystem of that community. The members of that community cause various changes so that ecological succession starts.
So, option A is the correct answer.
In grassland ecosystem, the pyramid of biomass is
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Linear
0%
Upright
0%
Inverted
0%
Inverted upright
Explanation
In grassland ecosystem, the shape of pyramid of biomass is upright. This pyramid is called as pyramid of biomass. Pyramid of biomass represents the total mass of organisms at each trophic level. In grassland ecosystem, the biomass at the base is maximum followed by that in primary consumers (herbivores), followed by that in secondary consumers (carnivores). The base of the pyramid of biomass represents the producers in a pond ecosystem. The secondary carnivores have least biomass in a grassland ecosystem.
Thus, the correct answer is 'Upright.'
Succession is
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Orderly process of community change till stability.
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Gradual convergent, directional and continuous process.
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Series of biotic communities that appear generally in barren area.
0%
All of the above.
Explanation
Ecological succession is a process in which different communities grow one by one in an ecosystem. The last community that invades an ecosystem is the climax community. It is the most evolved form of community that remains stable until the ecosystem is destroyed. Ecological succession is a diverse process. It generally starts on a barren land.
So, all of the above options are correct. Option D is the correct answer.
The correct order of succession in xerarch is
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Annual herb stage, perennial herb stage , lichen moss stage , scrub stage forest
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Perennial herb stage , annual herb stage, lichen moss stage , scrub stage forest
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Lichen moss stage , annual herb stage , perennial herb stage , scrub stage forest
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Forest , scrub stage , annual herb stage perennial herb stage , lichen moss stage.
Explanation
Xerosere
is a plant succession
theory that is limited by water availability.
So, the stages in correct order iare bare rocks, crustose lichen stage,
foliose lichen stage, moss stage, annual herb stage, perennial herb stage, shrub stage and forest.
The correct answer is option C.
In ecological succession, the climax community is best recognised by the following state
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P = R
0%
P > R
0%
P < R
0%
P $$\neq$$ R
Explanation
A climax community is the last community to arrive in an ecological succession before it's destruction. It is the most stable of all the communities. In this type of community, the Productivity and Respiration rates are equal. So, in a climax community, P=R, which is equal to 1.
So, option A is the correct answer.
Correct sequence of plants in a hydrosere is
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Pistia
$$\rightarrow$$
Volvox
$$\rightarrow$$
Scirpus
$$\rightarrow$$
Hydrilla
$$\rightarrow$$ Oak $$\rightarrow$$
Lantana
0%
Oak $$\rightarrow$$
Lantana
$$\rightarrow$$
Volvox
$$\rightarrow$$
Hydrilla
$$\rightarrow$$
Pistia
$$\rightarrow$$
Scirpus
0%
Oak $$\rightarrow$$
Lantana
$$\rightarrow$$
Scirpus
$$\rightarrow$$
Pistia
$$\rightarrow$$
Hydrilla
$$\rightarrow$$
Volvox
0%
Volvox
$$\rightarrow$$
Hydrilla
$$\rightarrow$$
Pistia
$$\rightarrow$$
Scirpus
$$\rightarrow$$
Lantana
$$\rightarrow$$ Oak
Explanation
Hydrosere, originating in water(pond, pools, lakes, etc.) and starts with the colonization of some phytoplanktons which form the pioneer plant community, and finally terminates into a forest, which is a climax community together with their chief components of vegetation. The various stages together with their components of plant species of a hydrosere are phytoplankton stage, rooted submerged stage, rooted floating stage, reed swamp stage, marsh or sedge meadow stage, woodland stage and climax forest stage. Volvox is phytoplankton, Hydrilla is a rooted submerged plant, Pistia is rooted floating plant, Scirpus is reed swamp plant, Lantana is sedge meadow plant & oak is a woody tree.
So, the correct answer is 'D'.
The species though insignificant in number determines the existence of many other species in a given ecosystem
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Extinct species
0%
Endemic species
0%
keystone species
0%
Sacred secies
Explanation
A keystone species is a plant or animal that plays a unique and crucial role in the way an ecosystem function. Without keystone species, the ecosystem would be dramatically different or cease to exist altogether. Some keystone species, such as the wolf, are also apex predators. Keystone species have a disproportionately large effect on the communities in which it occurs. Such species help to maintain local biodiversity within a community either by controlling populations of other species that would otherwise dominate the community or by providing critical resources for a wide range of species.
So, the correct answer is 'keystone species'.
Stage of hydrarch are :
(a) Marsh meadow stage (b) Reed swamp stage (c) submerged plant stage (d) Phytoplankton stage
(e) Submerged free-floating stage.
Identify the correct sequence :
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d , c, e , b , a
0%
c , e , a , b , d
0%
b , d , c , a , e
0%
d , e , c , b , a
0%
e , c , b, a , d
Explanation
Development of biotic organisms in a newly formed pond or lake is called hydrosere or hydrarch.
It starts as soon as the muddy water becomes clear. The stages includes
1. Phytoplankton stage
2. Submerged plant stage
3. Floating plant stage
4. Reed swamp stage
5. Marsh meadow stage
6. Woodland stage
7. Forest stage
Select the correct matches :
(a) Sedimentary nutrient cycle - Nitrogen cycle (b) Pioneer species - Lichens (c) Secondary succession - Burnt forest (d) Pyramid of biomass in sea - upright
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a, b, and d only
0%
b, and c only
0%
a, and c only
0%
b, and d only
Explanation
a) The sedimentary cycle is different from the nitrogen cycle. Sedimentary nutrient cycle deals with elements like
iron, calcium, phosphorus, sulfur, and other more-earthbound elements.
b) Pioneer species
are the first
species
to enter an area after a disturbance. They are the colonizers. The species like
bacteria, fungi, and
lichens constitutes the first stage of ecological succession.
c) Secondary succession takes place in a place that has been destroyed due to fire, floods, and other natural calamities. It includes burnt forests, logging of forests, etc.
d)
The
pyramid of biomass in the sea
is not upright. It is
inverted
because the
biomass
of fishes far exceeds the phytoplankton population.
So, option b and c are correct
Figs belong to
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Keystone species as they show animal dependent pollination.
0%
Keystone species as they produce food and provide protection to animals during the lean period.
0%
Critical link species as they form connecting link between trees and herbs.
0%
Critical link species as they establish essential links for absorbing nutrients from the soil and organic residues.
Explanation
Figs are one of the most important plant species of a rainforest ecosystem. There are close to 1,000 different species of Ficus, which can be found in every major rainforest, tropical continent and islands around the world. Hundreds of animals like pigeons, parrots, hornbills, toucans, monkeys, gibbons, and fruit-eating bats, feed on the sweet fruit of the fig tree. Figs are considered a "keystone" species because they are so important to the animals of the rainforest. This is so because figs bear fruit several times a year. Different species of figs fruit at different times so that there is always a supply of food for animals that depend on fruit as a major part of their diet. A large variety of herbivores and omnivores eat figs. In some forests up to 70% of its animal's diets depend on figs,and the number of fruit-eaters determines the number of predators of fruit-eaters.
So, the correct answer is 'B'.
Which one is first colonizer of bare rock/pioneer community in xerarch?
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Annual herb
0%
Perennial herb
0%
Lichen/Moss
0%
Scrub
0%
Forest
Explanation
Xerarch originally refers to dry habitat. A dry habitat can sustain only a certain number of living organisms. These organisms can live in the xerarch ecosystems. Crustose lichens and mosses are the ones that grow in a xerarch. Lichens are one of the most primitive organisms. They existed even when the lithosphere was not there.
So, option C is the correct answer.
Different communities appearing and replacing one another are called
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Climax communities
0%
Seral communities
0%
Serial communities
0%
Successive communities
Explanation
In the process of ecological succession in which
, a specific area of land is invaded by many communities. The first community to invade is called the pioneer community. Followed by pioneer community, there are many seral communities that invade the area. Finally, there comes a stable community that does not get replaced and is the final one, and it is called the climax community. So, option B is the correct answer
The pyramid which cannot be inverted in a stable ecosystem is that of
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0%
Biomass
0%
Number
0%
Energy
0%
All the above
Explanation
Flow of energy declines as it passes from lower to higher trophic level. The energy decreases from one trophic level to the next trophic level because energy is lost as metabolic heat during transfer of energy. Hence, the pyramid of energy is always upright in any ecosystem and it cannot be inverted in a stable ecosystem. When food energy passes from producers to herbivores to carnivores, only 10% of energy is transferred from one trophic level to another trophic level.
Thus, the correct answer is 'Energy.'
Pyramid of numbers deals with number of
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Species in an area
0%
Individuals in a community
0%
Individuals in a trophic level
0%
Subspecies in a community
Explanation
Pyramid of numbers in a food chain deals with the number of individuals in a trophic level. It is upright in pond/grassland ecosystem. In this, the energy is maximum at producer level, followed by primary consumer level (herbivores), followed by secondary consumer level (carnivores). The base of the pyramid of number represents the producers in an ecosystem.
Thus, the correct answer is 'Individuals in a trophic level.'
Sedimentary cycle having a small gaseous component is found in
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Phosphorus
0%
Nitrogen
0%
Carbon
0%
Sulphur
Explanation
Sedimentary cycle consists of weathering of an existing rock followed by the erosion of minerals, transport and deposition. It has earth's crust as the reservoir pool.
Sedimentary cycle having a small gaseous component is found in sulphur. Other sedimentary cycles include iron cycle, calcium cycle.
Thus, the correct answer is 'Sulphur.'
Lithosphere is reservoir of
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Carbon
0%
Oxygen
0%
Phosphorus
0%
Nitrogen
Explanation
There are 4 layers of Earth, namely lithosphere (land), hydrosphere (water), biosphere (living), and atmosphere (air). Lithosphere of Earth includes the crust and the uppermost mantle. It makes up the hard and rigid outer layer of the Earth. It is reservoir of phosphorus. The largest reservoir of phosphorus is sedimentary rocks.
Thus, the correct answer is 'Phosphorous.'
Pyramid of energy (in a forest/pond ecosystem) is
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0%
Always inverted
0%
Always upright
0%
Spindle - shaped
0%
Both upright and inverted depending upon ecosystem
Explanation
In pond and forest ecosystem, the shape of pyramid of energy is upright. In this, the energy is maximum at producer level, followed by primary consumer level (herbivores), followed by secondary consumer level (carnivores). The base of the pyramid of number represents the producers in a forest and pond ecosystem.
Thus, the correct answer is 'Always upright.'
Crystalline rocks are natural source of
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0%
Calcium
0%
Phosphorus
0%
Magnesium
0%
Sulphur
Explanation
There are 4 layers of Earth, namely lithosphere (land), hydrosphere (water), biosphere (living), and atmosphere (air).
The lithosphere of the Earth makes up the hard and rigid outer layer of the Earth. It is a reservoir of phosphorus.
The largest reservoir of phosphorus is sediments or sedimentary rocks.
Crystalline rocks are sedimentary rocks. They are the natural source of phosphorous.
Thus, the correct answer is 'Phosphorous.'
Both hydrarch and xerarch successions lead to
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0%
Medium water conditions
0%
Excessive wet conditions
0%
Xeric conditions
0%
Highly dry conditions
Explanation
Correct option: A
Explanation:
Hydrarch succession
is the succession on any kind of water body.
The pioneer species over here are the
phytoplankton
and that of the climax community is the
forest.
Xerarch succession
occurs on any kind of bare land/rock.
Here, the pioneer species is
lichen
and the final community is
forest.
Both the succession leads to medium conditions.
Hence, b
oth hydrarch and xerarch successions lead to "
m
edium water conditions".
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Practice Class 12 Medical Biology Quiz Questions and Answers
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