CBSE Biology Notes for Class 12 – What is a Habitat and Niche?
Online class 12 : What is a Habitat? Biology notes for Class 12
Habitat Meaning
Habitat is defined as a natural home or environment where an organism lives. In other words, Habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or any other organism.
The term typically refers to the zone in which the organism lives and where it can find food, shelter, protection, and mates for reproduction. It is the natural environment in which an organism lives or the physical environment that surrounds a species population. A habitat is made up of physical factors such as soil, moisture, the range of temperature, and light intensity as well as biotic factors such as the availability of food and the presence or absence of predators. Every organism has certain habitat needs for the conditions in which it will thrive, but some are tolerant of wide variations while others are very specific in their requirements. A habitat is not confined to a geographical area, but it can be the interior of a stem, a rotten log, a rock or a clump of moss, and for a parasitic organism it is the body of its host, part of the host’s body such as the digestive tract, or a single cell within the host’s body.
Habitat types include polar, temperate, subtropical and tropical. The terrestrial vegetation type may be forest, steppe, and grassland, semi-arid or desert. Freshwater habitats include marshes, streams, rivers, lakes, ponds, and estuaries, and marine habitats include salt marshes, the coast, the intertidal zone, reefs, bays, the open sea, the seabed, deep water and submarine vents.
Habitats change over time. This may be due to a violent event such as the eruption of a volcano, an earthquake, a tsunami, a wildfire or a change in oceanic currents; or the change may be more gradual over millennia with alterations in the climate, as ice sheets and glaciers advance and retreat, and as different weather patterns bring changes of precipitation and solar radiation. Other changes are the result of human activities; deforestation, the ploughing of ancient grasslands, the diversion and damming of rivers, the draining of marshland and the dredging of the seabed. The introduction of alien species can have a devastating effect on native wildlife, through increased predation, through competition for resources or through the introduction of pests and diseases to which the native species have no immunity.
For question answers of Habitat and Niche, click on NCERT Class 12 Biology
What is a Niche? Biology notes for Class 12
A niche is a term that defines an organism’s role in an ecosystem. Not only does a niche include the environment a given organism lives in, it also includes the organism’s “job” in that environment. A niche may also encompass what the organism eats, how it interacts with other living things or biotic factors, and also how it interacts with the non-living, or abiotic, parts of the environment as well.
All living organisms have a fundamental niche. It is defined as all the possibilities available for the organism to take advantage of i.e. all possible sources of food, all open roles in the environment. Thus, any suitable habitats are included in a fundamental niche. It is the full potential range of physical, chemical and biological conditions and resources that an organism can utilize if there is no competition from other species. But in particular ecosystem, the species often compete with one another for one or more of the same resources. This means the niches of competing species overlap.
Species can either separate and minimize competition(lower the niche overlap) by becoming a resource specialist.
In reality, an organism is not going to use all suitable resources in an environment at the same time. To survive and avoid competition for the same resources, a species usually occupies only part of its fundamental niche in an ecosystem which is called as realized niche. It means, there is the more specific role that organisms play.
For keynotes and videos on Habitat and Niche, click on CBSE Biology Class 12.
Factors affecting an organism’s niche
- Symbiotic relationships play an important role in determining an organism’s niche.
- Predators in a given area can limit an organism’s niche and particularly where it can find safety and shelter.
- Competitors also limit food sources and other nutrients needed, so they can also have an effect on where an organism makes its home. An organism may also seek out other species to have positive interactions with in order to define its niche.
- Commensalism and mutualism with other species in the area can make an organism’s life easier.
- Abiotic factors such as water availability, climate, weather, and in the case of plants, soil types, and amount of sunlight can also narrow a fundamental niche to a realized niche. An organism can somewhat adapt to their environment, but the basic needs must be met first in order for them to have time to find their niche.
Read more Biology notes for class 12, click 12th Science section
Takshila Learning is one of the most innovative and success oriented online coaching sites in India. For more inquiries, CBSE Class 12th Biology, Chemistry, Physics, Maths, articles, video lectures, CBSE exam alerts, Syllabus, sample papers for Class 12th, register with Takshila Learning.
Follow us on a Social media
Call us: 8800999280/83/84 or fill the form for any other details:
0 responses on "CBSE Biology Notes for Class 12 - What is a Habitat and Niche?"