BIOLOGY MCQ

Euglena

Wallace

Mutation

When different groups of animals show similar adaptations due to similar environmental conditions, it is called convergent evolution, which is caused by adaptive convergence.

Phylogeny

Amphibians are absent in Galapagos islands as they could not leave the mainland and travel to the island by crossing saline water.

Firstly there is no water on the moon which is the first and foremost requirement for the life. Life first started on the earth because of water and if no water we can imagine no life. Air is also required to breathe and no air is on the moon or we can say that oxygen is required by human beings to breathe is not enough on the moon for the survival.

Herbert Spencer.

Atmosphere is the layer of air enveloping the earth at the height of around 1600 km and it consists of many gases. The major components of the atmosphere are nitrogen, oxygen and water vapour. The minor components are argon and carbon dioxide, the trace components include inert gases like methane.
The atmosphere protects us from meteors and harmful solar radiation and warms the earth's surface by heat retention. Earth's atmosphere has primary five layers, referred to as spheres. From the lowest to the highest layer, they are the troposphere, stratosphere, mesosphere, thermosphere and exosphere.
These five distinct layers have been identified using thermal characteristics, chemical composition, movement and density.

Neanderthal mans are not the direct ancestors of humans. But obviously we share a common ancestry. Human evolutionary tree consist of branches.

Oparin and Haldane.

Lamarckism was wrong in inheritance of acquired characters.

Divergent evolution.

Fingernails.

Huge meteorites struck earth somewhere around modern Mexico. These meteorites were rich in Iridium an element rare on earth. Strike of meteorites brought in a number of drastic changes in environment and climate and set in huge forest fires. All of these changes might be associated with mass extinction at the end of Mesozoic era. However, an alternative view is that meteorites did strike earth, and mass extinction had happened before the strike of meteorites and meteorites strike was not the cause of mass extinction. Exactly what happened, we still do not know.

Small isolated population.

Biogenetic law.

Adaptive radiation.

Darwin finches occupy different niche with in the same geographical area and the distribution is primarily decided by the differences in diet of birds.

The dominant animals during the Jurassic period were dinosaurs.

Chimpanzee

Shortening of jaws.

Ammonia, amino adds, proteins, nucleic acids.

Essay on Population by Malthus.

Convergent evolution.

The theory of evolution states that the organism change gradually in order to adapt easily to the environment. The process by which an organism changes its heritable characteristics for better adjustment to the environment is known as evolution.
Man and apes had common ancestors known as chimpanzees. The chimpanzees during the course of evolution underwent changes and formed a more complex organism like man and apes. They share common mutation rates.

Scientists have developed a theory that describes how the very first microscopic life on primitive Earth could have evolved as a result of a series of chemical reactions. This theory is called chemosynthesis, and it describes the chemical evolution of cellular life.
Chemosynthesis, process in which carbohydrates are manufactured from carbon dioxide and water using chemical nutrients as the energy source, rather than the sunlight. It starts when random molecules in the atmosphere of primitive earth form simple organic molecules with energy provided by ultra violet light, radiation and other energy sources.
The chemosynthesis theory implies that the development of life is probable wherever the proper physical and chemical conditions are in place.

Darwin

Lobe fish shows characters from cartilaginous fishes and from amphibia. They belong to bony fishes. Since, they show characters from two other groups of animals, they are considered as link species.

Abiogenesis of primitive polypeptides, the pro-proteins, in primitive sea was followed by formation of large spherical colloidal aggregates of proteins that remain suspended as droplets in sea water. It was driven by dehydration/opposite charge attraction. The hydrophilic amino acids attracted water molecules and led to formation of a water envelop around each aggregate.
Aggregation of fat/lipid molecules formed a coating membrane around each aggregate to hold the colloidal particles together thereby facilitating chemical reactions among them. A protobiont/eobiont/protocell is defined as aggregate of abiotically produced organic molecules surrounded by non-unit membrane.
Thus, the above mentioned colloidal aggregate is protobiont/eobiont/protocell. It is called so because of its role as progenitor of first life form, the prokaryotic bacteria like cell.

Dogfish and whale.

Sedimentary rocks.