Organisms and populations: Environment and abiotic factors

Introduction

Environment is what surrounds us . It has plants , animals , humans and many microbial forms . 

A Species is a assemblage of a type of organism that can interbreed to form fertile offspring . For eg. all humans can interbreed and constitute a Species . Similarly all dogs can reproduce among themselves and make a Species . All members of a Species resemble each other morphologically and genetically . Different species in a environment interact with each other as well with their environment. 

We human take oxygen gas which is produced by green plants . Green plants in turn are dependent on carbon dioxide gas produced in respiration of plants and animals. Each organism thermodynamically a open system exchanging matter and energy with surroundings.

An organism normally  occupy a space in environment which is termed as it's habitat . In it's habitat a Species lives , feeds ,  mates and interact with other species it encounter .

In an environment living components like plants , animals and microbes form biotic factors and non living things like air , water , light form abiotic factors . An organisms interact with both biotic and abiotic factors  .

In nature we see different types of species co living at a place . They are in different numbers . Some make large populations and others make small sized populations. 

A population is a group of organisms of same species living at same place like pond , forest , desert or ocean .E.g. Tuna fish population , stick insect population , human population.

Forests, pond and desert are termed as ecosystem as they are unit of biosphere made of biotic and abiotic components .

Inside an ecosystem a Species has a definite "niche ". A niche can be understood as profession of an organism whereas habitat as house address . Niche involves how an organism interact with its environment for e.g what response it gives to abiotic factors like light , water , wind and biotic factors like prey and predator .Eagle and Kite if living at same place they have to exhibit different ecological niche otherwise there will be fierce competition between them .

Questions :

Q1. What is ecology ?

Ans. It is the branch of biology which deals with interaction of organisms with other organisms and environment.

Q2. What are various levels in ecology ?

Ans. Organismic level , population level , Community level and biome level 

Q3.What causes annual variation in seasons on earth 🌍?

Ans. Tilt of earth axis 23.5 degree ( also called obliquity of ecliptic ). Due to this sun shines at different latitude at different angles throughout the year .

Second reason rotation of our planet earth around sun .

Q.4 Name some biomes on earth.

Ans. Arctic and Alpine Tundra , desert , rainforests , temperate forests , coniferous forests , grasslands , deciduous forest .

Q.5 What major abiotic factors affect habitat and organisms living there ?

Ans . Temperature , light , water , soil .

Q.6 How does temperature as abiotic factors affect ecological life of organism ?

i) Temperature affect metabolism of organism 

ii) It affect solubility of gases like oxygen in water for aquatic organisms

iii) It affects distribution of animals and plants . 

iv) Most of the chemical reactions increase as temperature is increased but at higher temperatures enzymes denature and stop the reaction. 

v) Temperature affect flowering and photosynthesis in plants also .

vi ) Eurythermal animals can tolerate wide range of temperature but stenothermal animals can tolerate narrow range of temperature. 

Q. 7 Why mango trees don't grow in temperate area like Canada ?

Ans . Mango is a tropical climate crop so it require higher temperatures for its growth and same is not available in temperate areas .

Q.8 Why snow leopard is not seen in Kerala ?

Ans. Snow leopard is adapted to low temperature climate in mountains so it can not bear high heat of Kerala and it's rainy season .

Q.9 Why water is an important abiotic factor in ecology ?

Water is required in metabolic reactions .It is an universal solvent for many chemical reactions. Photosynthesis is dependent on water for providing electron and hydrogen ions . Photolysis of water produces oxygen gas in plants .

Distribution of plants on earth also depend on water availability.

Salinity and pH of water also affect organisms . Some organisms are high salinity tolerant( euryhaline) and others are low salinity tolerant ( stenohaline) .

Due to osmotic problems most of sea organisms can not live in fresh water .

Q.9 What is the role of light in ecology?

Ans. Photosynthesis light reaction involves light induced formation of ATP and NADPH 

Light also affect growth of plants and flowering in short day and long day plants .

Light is required for vision in animals .

Animals also are classified as nocturnal and diurnal due to their activeness in night and day respectively.

Light affect reproductive physiology of birds by their effect on pineal gland .

Q.10  How soil becomes an important abiotic factor in ecosystem?

Ans. Soil contain mineral and water for growth of plants .

It also hold plants in position. It provide habitat for animals and microbes and cause decomposition of detritus . Soil may be rich or deficient in water this affecting life of organisms which require moisture e g. Earthworm . Nutrient cycling is almost impossible without this reservoir .