AGE DISTRIBUTION AND AGE PYRAMID

 Age distribution - Every population has individual different age groups .

Then the individual of a population is divided into 3 classes

1) Pre-reproductive

2) Reproductive

3) Post-reproductive

Age pyramid - Age pyramids are the graphics representation of different age groups found in a population with Pre-reproductive group at the base reproductive ones in the middle and the Post-reproductive groups at the top.

a) Juvenile age pyramid

Juvenile age pyramid is triangular shape.

The pyramid with a brought base has high percentage of young population due to high birth rate .

Such a pyramid which has less number of reproductive and old in dividule of population called as Juvenile.

b) Stable age pyramid

Stable age pyramid is ballet shaped .

The number of Pre-reproductive and reproductive individuals are almost equal .

Post-reproductive individuals are comparatively the population size is stable.

c) Contracting age pyramid

Contracting age pyramid is urn-shaped .

An urn-shaped pyramid has a narrow base with number of young individual because of low birth rate .

The reproductive and post-reproductive are more such a population is called dying and contracting.

The number of Post-reproductive individuals is also sizeable.

FUNCTION OF ECOSYSTEM

The function of ecosystem are

a) Food chain

b) Food web

c) Energy flow

d) Trophic level or Ecological pyramid

a) Food chain - Food chain is defined as the transfer of energy and nutrients through the continuous process of  " eating  and being eaten" .

The plants and animals of an ecosystem are linked link is known as food chain.

Food chain divided into 3types 

I) Terrestrial Food Chain 

II) Grass Food Chain

III) Aquatic Food Chain

Example

b) Food web

In an ecosystem the various food chain are inter-connected with each other and it is called as food web.

In an ecosystem , normally the food chain never separate as isolated unit but are inter-connected with one another to form network of food chain called food web.

A particular organisms may not occupied the same trophic level in every food chain , it may behave as secondary , tertiary consumer.

Hence food chain are inter-connected with another through different types of organisms at different trophic level.

Food web maintain the stability of an ecosystem . More complex the food web , more stable in the ecosystem .

Example:

c)Energy flow

Sun is the ultimate source of energy.

Flow of energy takes place from the producer to the decomposed.

Thus energy flow in an ecosystem is always unidirectional .

It is based on two important laws of thermodynamics.

#) First law of thermodynamics :  It state that energy can neither be created nor be destroyed but can be converted from one form to another form.

#) Second law of thermodynamics : It state that energy can't be transferred 10% from one form to other form.

During tranfer from one form of energy to another form a part of concentrated enery is converted into degraded energy and the rest amount is lost during transfer.

Example: In our domestic electric supply electric energy in converted into light energy through illumination of electric bulb.

The total electric energy spent for illustration is not converted 10% into light energy .

Apart of it is converted into light energy and rest is lost as heat energy produced by electric bulb .

10% Rule of energy flow : 

Lindemann in 1942 proposed the 10% rules of energy flow and according to him , about 10% of energy is transferred from one trophic level to the next trophic level.

If in an ecosystem the net primary production is 100cal the secondary production at herbivores leave would be 10cal ,at primary carnivorous would be 1cal ,at secondary carnivorous would be 0.1 cal

d) Ecological pyramid

An ecological pyramid is a graphic representation of an ecological parameters , like biomass energy or number of individuals present in different trophic level of a food chain .

Ecological pyramid were first prepared by Elton in 1927 . Hence they are also called as eltonian pyramid.

In a pyramid , the various steps of a food chain are represented by the sequence . The producers are placed at the base of the pyramid and the top of the pyramid and primary carnivorous are placed between the top and base level of the pyramid.

An ecological pyramid may be upright or inverted . 

Depending upon different parameters the ecological pyramid is 3 types

#) Pyramid of number

#) Pyramid of biomass

#) Pyramid of energy 

#) Pyramid of number

It is a graphic representation of the no of individuals per unit area of various trophic level i.e. number of producer herbivores and carnivorous .

The base of the pyramid contain the number of producer where as the number of carnivorous are occupied at the top of the pyramid.

The pyramid of numbers may be upright or inverted .

In grass land ecosystem the pyramid of numbers is upright . Because the number of grass or the producer is large as compared to herbivores and carnivorous the top of the pyramid include a small or few number of carnivorous 

But in case of parasitic food chain the pyramid of number.

#) Pyramid of biomass

Biomass is the total mass of the organisms.

It is measured both as fresh and dry weight .

Pyramid of biomass is a graphic representation of biomass is present per unit area of different trophic level comparision produser at the base and top carnivorous at the top of pyramid .

Pyramid of biomass is more real than the pyramid of number .

Pyramid of biomass is upright in grass land ecosystem and inverted in the Ponds or aquatic ecosystems.

In grass land or forest maximum biomass occure in producer and it gradually decreases from the base to the top.

The herbivores and carnivorous has very low amount of biomass.

ECOSYSTEM

The term ecology was first proposed by A.G. Tansley in 1935 but the concept appearced much later . 

An ecosystem is a community of living organisms interacting with each other and their non-living environment.

What makes up an ecosystem?

• All living things (  Biotic) (plants, animals, and bacteria)

• Non living things   (Abiotic)  (the sun, rocks, and soil)

OR

An ecosystem is an ecological unit which includes both biotic and abiotic components.

Ecosystem is the interaction of both biotic and abiotic components.

In other words , Ecosystem is a self- regulated and self-sustaining structural and functional unit of nature which consists of a community of living beings and it's physical environment , both interacting and exchanging materials between them.

Ecosystem can be small and large

Ecosystem is an open system and it has no boundaries.

• Abiotic - # Sunlight

                  # Air

                  # Soil

                  # Temprature

• Biotic -   #Producer (green plants)

                  #consumer

Consumer are divided into 3 types

# Primary consumer

# Secondary consumer

# Tertiary consumer

# Primary consumer

A primary consumer is an organism that feeds on primary producers. ... Primary consumers are usually herbivores that feed on autotrophic plants, which produce their own food through photosynthesis.

# Secondary consumer

Secondary consumers are largely comprised of carnivores that feed on the primary consumers or herbivores. Other members of this group are omnivores that not only feed on primary consumers but also on producers or autotrophs. An example is a fox eating rabbit.

# Tertiary consumer

A tertiary consumer is an animal that obtains its nutrition by eating primary consumers and secondary consumers. Usually tertiary consumers are carnivorous predators, although they may also be omnivores, which are animals that feed on both meat and plant material.

EXOSPHERE

The exosphere is the uppermost region of Earth's atmosphere as it gradually fades into the vacuum of space. The air in the exosphere is extremely thin - in many ways it is almost the same as the airless void of outer space.

The exosphere has gases like hydrogen and helium, but they are very spread out. There is a lot of empty space in between. There is no air to breathe, and it's very cold.

The air in the exosphere is very thin, and is made up mostly of helium, and hydrogen. Traces of other gases such as atomic oxygen and carbon dioxide can also be found. The upper level of the exosphere is the farthest point from earth that is still affected by earth's gravity.

THERMOSPHERE

The thermosphere is a layer of Earth's atmosphere that is directly above the mesosphere and below the exosphere. It extends from about 90 km (56 miles) to between 500 and 1,000 km (311 to 621 miles) above our planet. ... Solar activity strongly influences temperature in the thermosphere.

. Radiation causes the atmosphere particles in this layer to become electrically charged particles, enabling radio waves to be refracted and thus be received beyond the horizon.

The highly attenuated gas in this layer can reach 2,500 °C (4,530 °F) during the day. Despite the high temperature, an observer or object will experience cold temperatures in the thermosphere, because the extremely low density of the gas (practically a hard vacuum) is insufficient for the molecules to conduct heat. A normal thermometer will read significantly below 0 °C (32 °F), at least at night, because the energy lost by thermal radiation would exceed the energy acquired from the atmospheric gas by direct contact. In the anacoustic zone above 160 kilometres (99 mi), the density is so low that molecular interactions are too infrequent to permit the transmission of sound.

MESOSPHERE

The mesosphere is a layer of Earth's atmosphere. The mesosphere is directly above the stratosphere and below the thermosphere. It extends from about 50 to 85 km (31 to 53 miles) above our planet. Temperature decreases with height throughout the mesosphere.

is directly above the stratosphere and below the thermosphere.

extends from around 50-85 km above our planet (31-53 miles)

possess temperatures that decrease with height throughout the mesosphere.

contains strong zonal winds (east-west), atmospheric tides, planetary waves, and gravity waves.

STRATOSPHERE

The stratosphere is a layer of Earth's atmosphere. It is the second layer of the atmosphere as you go upward. ... The bottom of the stratosphere is around 10 km (6.2 miles or about 33,000 feet) above the ground at middle latitudes. The top of the stratosphere occurs at an altitude of 50 km (31 miles).

The stratosphere is where you'll find the very important ozone layer. The ozone layer helps protect us from ultraviolet radiation (UV) from the sun. In fact, the ozone layer absorbs most of the UV radiation the sun sends to us. Life as we know it wouldn't be possible without this layer of protection.

Temperature Inversion. The lower layers of the stratosphere are colder & as we move upwards, the upper layers become hotter. ... 

Temperature Increases With Height. ... 

The Stratosphere Is Where Jets Like to Fly.