Biology Test - 57

Ecosystem diversity deals with the variations in ecosystems within a geographical location and their overall impact on human existence and the environment. Ecological diversity is a type of biodiversity. It is the variation in the ecosystems found in a region or the variation in ecosystems over the whole planet.

An example of chemotropic movement can be seen during the growth of the pollen tube, where growth is towards the ovules. Fertilization of flowers by pollen is achieved because the ovary releases chemicals that produce a positive chemotropic response from the developing pollen tube. An example of positive and negative chemotropism is shown by plant roots. The roots grow towards useful minerals displaying positive chemotropism and grow away from harmful acids displaying negative chemotropism.

When we move from dark to light, we fail to see for some time but soon visibility becomes normal. It isadaptation.

Adaptation is the ability of eye to focus according to different intensities of light. Retina has photoreceptor cells that sense light intensities. There are two types of photoreceptor cells, cones and rods. Cones are associated with daylight vision and colour vision while rods are associated with scotopic vision i.e. vision under low light. Whenever light intensity changes from high to low or vice versa, these cones and rods are activated at high and low light intensities respectively. The eye adapts itself to focus in different light intensities.

The sensory neuron enters the spinal cord through the dorsal root of the spinal nerve.

Sensory information is carried by sensory neurons in dorsal roots, which enter the cord in small bundles called dorsal rootlets. The cell bodies for these sensory neurons are clustered together in a structure called the dorsal root ganglion, which is found alongside the spinal cord.

The injecting of foreign gene in an animal gives rise to transgenic animal. Transgenic animals are animals that have had a foreign gene deliberately inserted into their genome. Such, animals are most commonly created by micro-injection of DNA into the pronuclei of a fertilized egg which is implanted into the oviduct of a pseudopregnant surrogate mother. 

Habitat loss and fragmentation is the most important cause driving animals and plants to extinction. When large habitats are broken into small fragments due to various human activities, mammals and birds requiring large territories and certain animals with migratory habitats are badly affected, leading to population declines. The same can be applicable to the plant (forest) loss and degradation as millions of species are being cut and cleared for the expansion of agricultural land, harvesting timber, forest fire, as well as overgrazing.

The residual volume of air in a normal human is \(1.1\) to \(1.2\) litre.

Residual volume is the amount of air that remains in a person's lungs after fully exhaling. Doctors use tests to measure a person's residual air volume to help check how well the lungs are functioning. It is normal to have some air remain after exhaling to keep the lungs from collapsing.

The method of bio-piracy is illegal collection of biological sample. Biopiracy is the term used to refer to the use of bio-resources bymultinational companies and other organisations without properauthorisation from the countries and people concerned withoutcompensatory payment.

Azithromycinis the 6-methyl derivative of erythromycin.

Azithromycinis the derivatives of the older macrolide antibiotic erythromycin. They are used in the treatment of a variety of infections, including community-acquired respiratory tract infections and mycobacterial infections

A gain or loss of chromosomes from the normal 46 is called aneuploidy. A common form of aneuploidy is trisomy or the presence of an extra chromosome in cells. Cells with one additional set of chromosomes, for a total of 69 chromosomes, are called triploids.