MCQ 11 Mark
What percentage of photo synthetically active radiation is in relevant solar radiation ?
- A100%
- B1-5%
- ✓50%
- D2-10%
Answer
View full question & answer→Correct option: C.
50%
C
50 questions · timed · auto-graded
Explanation:
The lithosphere is the solid crust or the hard top layer of the earth. It is made up of rocks and minerals.
The biosphere is a biologically inhabited part of earth along with its physical environment consisting of lower atmosphere, land, and water bodies.
The hydrosphere is the total amount of water on a planet.
An atmosphere is a layer of gas or layers of gases that envelope a planet and is held in place by the gravity of the planetary body.
Explanation:
Ecological pyramid is the graphic representation of an ecological parameter (number, biomass or energy).
The ecological pyramid can be upright, inverted or spindle shaped. The pyramid of energy gives graphic representation of flow of energy in different trophic levels. It is always upright because only 10 percent of energy is transferred from one trophic level to the next.
Explanation:
The transition in the species composition of a given area is called ecological succession.
During succession, the colonization of species in a particular area increases its population whereas, populations of other species decline and even disappear.
The present-day communities in the world have come to be because of succession that has occurred over millions of years since life started on earth.
Plant succession is a change which passes through definite developmental sequence and proceeds in a definite direction.
Explanation:
The climax community is stable, self-perpetuating and final community appearing in an area at the end of biotic succession, which is in perfect harmony with the climate of the area.
The vegetation in that particular area has been reached to a stable condition after ecological succession.
Explanation:
A. Arthur George Tansley coined the term ecosystem' in 1935 to describe the interactions between organisms and with their environment.
B. Odum was an American biologist who worked on ecosystem ecology and wrote the book 'Fundamentals of ecology'.
C. Eugenius warming was the first to write a textbook on plant ecology. He gave the concept and content on ecology.
D. Darwin gave a theory of natural selection which states that only fittest individuals are selected by nature and unfit ones are eliminated.
Explanation:
Phosphorus cycle is an example for sedimentary cycle.
A cycle which comprises the weathering of an existing rock, followed by the erosion of minerals, their transport and deposition, then burial, is called as sedimentary cycle.
First cycle sediments are characterized by the presence of less resistant minerals and rock fragments. If this material is reworked through a second cycle, the less resistant minerals will be eliminated or altered to more stable products.
The more sedimentary cycles, that a sediment has passed through the more mature, it will become and it will be dominated by well rounded resistant minerals.
Explanation:
The ecosystem is a segment of nature or biosphere consisting of a community of living beings and the abiotic or physical environment both interacting and exchanging materials between them. The ecosystem is defined as a functional unit of environment, which is independent and self-sustaining due to various interactions between abiotic and biotic components and different organisms among themselves.
Explanation:
The transition in the species composition of a given area is called ecological succession.
This takes place due to the change in the environmental conditions in a geographical area.
During succession, some species colonise an area and their populations become more numerous, whereas populations of other species decline and even disappear.
The time scale can be decades (for example, after a wildfire), or even millions of years after a mass extinction.
Explanation:
Biotic or ecological succession is the successive development of different biotic communities at the same site till a climax community develops there.
Primary Succession is the ecological succession on a primary base area like rock, or outcrop. It takes a long time of 1000 years or more.
Secondary succession is biotic succession on the secondarily bare areas e.g., an area devastated by forest fire or deforestation. It takes 50 to 100 years for grassland and 100 to 200 years for the forest. Ferns are generally the first to grow after forest fire because of their underground rhizomes.
Secondary succession is not completed if invaded by weeds like Sphagnum, Lantana, Eichhornia, Eupatorium.
Explanation:
The plants or the other autotrophic organisms which can prepare food require sunlight. In a cave, there will be very less availability of sunlight and hence primary productivity due to photosynthesis by green plants will be very low. Hence, a cave ecosystem is most unsuitable for primary productivity.
Explanation:
The succession which thus takes place through the process of living, growing and interactions of organisms with the effect of the environment within an area is referred as biotic succession.
Geographical succession is the directional change in the plant and animal community over a period of time in a specific area.
Physiographic succession is the directional change in the plant and animal community over a period of time in a specific area due to physical factors.
Climate succession is the directional change in the living community in a particular area over a period of time due to prevailing climatic conditions.
Explanation:
The appearance of living organisms on disturbed or damaged habitat is referred to as secondary succession.
Primary succession occurs in a barren land where no life existed before.
So, flooded land abandoned croplands and the area where organisms existed before exhibit the secondary succession.
Explanation:
The total quantity of solar energy converted into chemical energy by green plant is known as gross primary production.
A portion of gross production is used by the producers for their various metabolic activities.The remainder of energy after utilization is called as net primary production.
Losses due to respiration is seen in case of carbon cycle.
Explanation:
Pyramid of energy is a graphic representation of flow of energy in different trophic levels. It is always upright because only 10% of energy transferred from one trophic level to another. The energy level is maximum at the organisms occupying the base of the energy pyramid i.e., the producers and they are the most numerous organisms, while the consumers occupying the higher levels have less energy. As energy content keeps on decreasing so the number of organisms also decrease, at higher levels.
Explanation:
The gradual changes (succession) of micro-organisms in a microhabitat is known as micro succession or serule e.g., fungi, bacteria.
This type of succession occurs within communities, for example in dead trees, animal droppings, etc.
It is mainly affected by the conditions available for growth like oxygen, moisture, nutrient etc.
Explanation:
Decomposers include micro-organisms such as bacteria and fungi. They form the largest population in a food chain and obtain nutrients by breaking down the remains of dead plants and animals.
Explanation:
In an ecosystem, the rate of production or accumulation of organic matter per unit area per unit time is called productivity.
Plants are autotrophic. They perform photosynthesis by using solar energy to synthesize their own food. Hence they are the producers in an ecosystem.
The rate at which solar energy is stored by producers is called primary productivity.
Explanation:
The simplest of all nutrient cycles is phosphorus cycle as it exists in only one form and that is phosphate. Phosphorus is present either as a part of an organism, dissolved in water or in the form of rock and never makes its way into the atmosphere. The rocks with phosphate on coming in contact with water containing little acid undergo weathering and thus phosphorus goes into solution. Plants take this phosphorus through their roots and utilize it in various ways.