Biology 1 Marks Question

Oceans.

Spindle.

Earthworm, bacteria & fungi of decay and vulture.

Zooplankton are primary consumers in aquatic food chains that feed upon phytoplankton.
Therefore, they are present at the second trophic level in a lake.

Autotrophs.

Sunlight.

Gross productivity-Rate of production of organic matter during photosynthesis Net primary productivity -Available biomass for the consumption to heterotrophs/GPP-R = NPP.

There is unidirectional movement of energy the higher trophic level and its levels has a certain mass of living material at a particular time called as the standing crop. It represent values for dry blomass (standing crop).

Trees occupy vertical stratra, shrubs the second layer and herbs/grasses occupy the bottom layers/vertical distribution of species, at different levels.

Net primary productivity (NPP) is an ecosystem can be derived using the following equation:
NPP = GPP-R.
= (Gross – Primary Productivity) - (Respiratory Losses).

The ecological niche (of an organism) signifies the range of conditions it can tolerate, the resources it utilises, and its functional role in the ecological system.

It is because the biomass available to the consumer for consumption is a resultant of the primary productivity from plants.

It is defined as the amount of biomass or organic matter produced per unit area over a certain time period by plants during photosynthesis.

Heterotroph (as it does not have chlorophyll).

Grass, Amaranthus, Shrubby plants, Teak.

Stratification is the way in which different species in an ecosystem are placed or arranged vertically, occupying different levels. It is a way of minimising competition for limited resources vital for survival.

Phytoplankton - hydric → Submerged plant stage → Submerged free floating plant stage → Reed swamp stage → Marsh - meadow stage → Scrub stage → Forest stage - Mesic.

The part of the solar radiation which can be absorbed and used by the plants for photosynthesis, is called photosynthetically active radiation (PAR).

Net primary productivity refers to the biomass/ organic matter available at the producer level to the primary consumers, i.e. GPP-Respiratory losses. Gross primary productivity is the rate of production of biomass/ organic matter by producers during photosynthesis.

R represents the respiratory losses.

An individual transitional community in ecological succession.

Crow.

Man can be a primary as well as secondary consumer because man eats plants as well as meat of other animals. So, man is herbivores as well as carnivores.

About 71%.

Food web is formed by interconnecting food chains.

Pioneer species invade the area first.
For example, lichen.

The entire sequence of communities, that successively change in a given area resulting in a climax community, is called a sere.

Crustose lichens.

Tertiary consumer.

Gross primary productivity (GPP) – Respiratory loss (R) = Net primary productivity (NPP); it is the amount of energy/ biomass available in the producers for consumption by herbivores.

Constant solar input.

Producer or first trophic level.

The herbivores (primary consumers) which depend on plants for their food are called primary carnivores. They are also called secondary consumer.

Dead organic matter or remains of plant such as leaves, bark, flower and dead remain of animals, including faecal matter constitute detritus.

Tertiary consumer.

This is an example of primary succession: Because this begins from a state of little or no life.

The inorganic nutrients released from the humus by the microbes are used by plants as nutrients.

Both succession lead to medium water conditions (mesic), neither too dry, nor too wet.

Cockroaches and crows.

1. Productivity.
2. Decomposition.
3. Energy flow.
4. Nutrient cycling.

A constant input of solar energy is the ultimate source of all energy and requirement of any ecosystem to function and sustain properly.

The pyramid of biomass in sea is an inverted pyramid. It would have an upright pyramid of energy.

Pitcher plant is chlorophyllous and is thus capable of photosynthesis and act as producer.

Oceans contribute about 55 billion tonnes, which is about 32.5%.

Stratification.

The amount of energy or biomass remaining in a producer after meeting the cost of its respiration is called the net primary productivity.

Phytoplanktons are the dominant producers in aquatic ecosystem. Primary consumers are also known as herbivores.

The grazing food chain starts with producers while the detritus food chain starts with decomposers.

Natural and artificial ecosystem.

Some of the gross primary productivity gets lost in the form of respiration, that is why all primary productivity is not available for herbivores.

An ecosystem is a functional unit of nature, where biotic components (living organisms) interact among themselves and also with the abiotic environmental or physical factors.

Because when energy flows from a particular trophic level to the next trophic level, some energy is always lost as heat at each step.

The pyramid of biomass is inverted in a pond ecosystem because the biomass of fish (top consumer) is far larger than the producers (phytoplanktons).

Forest is the climax community for both successions.

Differences:

S.No.	Standing State	Strndirg Crop
(i)	Standing state refers to the amount of nutrients such as nitrogen, phosphorus, calcium, etc. present in the soil of an ecosystem at a given time.	Standing crop refers to the amount of biomass or organic matter available at a given rophic level/ ecosystem at a given time.
(ii)	It is in the abiotic comPonents.	It is in the biotic components.

Secondary consumers.

Fragmentation, leaching, catabolism, humification and mineralisation.

It states that only 10% energy of a trophic level is transferred to the next higher trophic level.

The rate of succession is much faster in secondary succession as the substratum (soil) is already present as compared to primary succession where the process starts from a bare area (rock).

Two factors that determine the vegetation and soil type of an ecosystem are:

1. Precipitation.
2. Temperature.

A considerable amount of gross primary productivity is used by the plants in respiration; so not all primary productivity is available for consumers.

Detritus.

He occupies third tropic level, i.e. he is a secondary consumer.

In a tree ecosystem.

Sunlight (solar radiation).

Grass (floor of forest) → Amaranthus → Shrubby plants → Teak (tree).

Shark.

Some of the organisms of DFC are prey to the animal of GFC, hence they are interlinked.

Green algae are autotrophic organisms, i.e. they synthesise their own food with the help of photosynthesis. At deepest layers of ocean, light is absent. So, photosynthesis does not take place there and hence, green algae are not found in deep strata

Natural or human induced disturbances like fire, deforestation, etc.

Population, community, ecosystem, biosphere.

The process of degradation of humus by microbial action and release of inorganic nutrients.

Man and sparrow.

It is the amount of living material or organic matter present in an organism, community or biome.

Oceans contribute about 55 billion tons organic matter.

The vertical distribution of different species occupying different levels in an ecosystem is called stratification. Trees occupy the topmost vertical layer of a forest, shrubs occupy the second layer and herbs and grasses occupy the bottom most or base layers.

Primary productivity is determined as the amount of biomass or organic matter produced per unit area over a time period by the plants during photosynthesis.

Net Primary Productivity (NPP) is the weight of the organic matter stored by the producers which is available to heterotrophs for consumption. It is equal to the rate of organic matter produced during photosynthesis GPP minus respiratory losses (R), i.e. NPP = GPP - R

Net primary productivity.

Measurement of biomass in terms of dry weight is more accurate because it avoids variations in weights due to seasonal moisture differences.

The entire sequence of communities that change in a given area.

Photosynthetically Active Radiation.

Photosynthetic Active Radiation.

The standing crop is measured as the mass of living organisms or the number in a unit area. The biomass of a species is expressed in terms of fresh or dry weight.

Atmosphere and oceans.

Many organisms occupy positions in different food chains and several food chains become interconnected to form a food web.

X and Z- Respiration and Y- Photosynthesis.

Energy exchange and flow of nutrient cycling

Two ways of measuring the standing crop of a trophic level are:

1. Biomass of living organisms.
2. Number in an unit area.

Standing crop represents total amount of living matter or organic matter present in an ecosystem in an unit area and at a specific time.

Ecological succession is a community controlled phenomenon, in which the structure and composition of communities change in an orderly and sequential manner, leading ultimately to the establishment of a climax community.

Lichens.

Temperature and soil moisture are the two climatic factors that regulate decomposition.

Fungi and bacteria.

Herbivores are the primary consumers; the rate of assimilation or formation of new biomass at the consumer level is secondary productivity.

They are all detritivores, i.e., decomposing organisms which feed on dead remains of plants and animals.

Producers.

Dissolved carbon in oceans and carbon in rocks, sediments and fossils are the two forms of carbon reservoirs.

It is in the atmosphere.

1. Rocks are the natural reservoir of phosphorus.
2. It is present in the form of phosphates.

Species composition refers to all the plant, animal and microbial species present in a given ecosystem.

Biotic and abiotic factors.

In the given equation for productivity in an ecosystem, GPP-R= NPP. 'R' represents the energy utilised by plants or producers in respiration. It is also referred to as respiration losses.

Producers and dead organic matter, respectively.

1. Dissolved carbon in oceans.
2. Carbon in fossil fuels.

'Stratification' in an ecosystem refers to the vertical distribution of different species occupying different levels.

Producers are also called transducers because they are able to change radiant or light energy into chemical form.

It is secondary succession.

The process of formation of humus from detritus or organic matter is called humification.

It is referred to the transfer of energy (food) from the producers through a series of consumers.

170 billion tons of (dry weight) organic matter.

A difference between c and gross primary productivity is:

S. No.	gross primary productivity.	net primary productivity
1.	It is the rate of production of biomass/organic matter by producers during photosynthesis.	It refers to the biomass/ organic matter available for the consumption to heterotrophs, left after some respiratory losses.

The community established at the terminal stage of succession, is called climax community.