Tag: zoology

Questions Related to zoology

Which of the following statements best explains the fact that 99.9% of all species that have ever existed on planet earth are now extinct?

zoology biodiversity, classification and conservation biodiversity losses biodiversity loss and need for conservation environmental conservation and biodiversity

  1. Climate changes associated with large comet or asteroid impacts occur faster than organisms can change themselves and adapt to the new environmental conditions.

  2. Genetic variations within a population occur through random mutations and given enough time, the environment will change in such a way that no existing genetic-based phenotypes permit survival.

  3. The accumulation of random mutations in the genome of all organisms eventually leads to frameshift mutations in critical genes and are ultimately lethal.

  4. The rapid increase in global temperatures in the past 100 years, combined with ocean acidification, heavy metal contamination, and ozone depletion caused by human activities have caused 99.9% of all of Earth's species to go extinct.

  5. All of the above

Show answer
Correct Option: E
Explanation:
The extinction of species can occur due to various reasons, organisms not being able to adapt to changing climatic conditions, human activities, genetic mutations that did not favor the survival of the species
So, the correct answer is 'All of the above'

Scientists believe that the Hawaiian island chain as it currently exists was formed as sea-floor spreading caused the Earth's crust to slowly move over a stationary point of volcanic activity in the mantle of the Earth.
While above the area of activity, volcanic eruptions formed the islands, and as sea-floor spreading moved the newly formed island off the area of activity, other new islands formed leading to the seven islands that now exist. The largest island in the chain is the only one that is currently volcanically active, suggesting that it is still above the active region on the mantel.
If this is true, which of the following should be observed?

zoology biodiversity, classification and conservation biodiversity losses biodiversity loss and need for conservation environmental conservation and biodiversity

  1. Species on the largest island will be more closely related to those of more distant islands than to those of closer islands.

  2. The largest island will have an extensive fossil record.

  3. The largest island should have less biodiversity than the other islands.

  4. Evidence of adaptive radiation should be most observable on the oldest of the seven islands.

Show answer
Correct Option: C
Explanation:
The island that is volcanically active will not have organisms inhabiting the area, those that may inhabit will burnt or turned into ashes so, there are no chances of having a fossil record. However due to periodic volcanic activity the island will have reduced biodiversity
So, the correct answer is 'The largest island should have less biodiversity than the other islands'

Which one has become endangered due to extinction of Dodo (Raphus cucullatus)?

zoology biodiversity, classification and conservation biodiversity losses biodiversity loss and need for conservation environmental conservation and biodiversity

  1. Sideroxylon grandiflorum

  2. Chrysanthemum

  3. Cinchona

  4. Bacillus thuringiensis

Show answer
Correct Option: A
Explanation:

Sideroxylon grandiflorum is a long-lived tree in the family Sapotaceae, endemic to Mauritius. It is also known as tambalacoque or dodo tree. It is valued for its timber. Stanley Temple hypothesized that the dodo, which became extinct in the 17th century, ate tambalacoque fruits, and only by passing through the digestive tract of the dodo could the seeds germinate. Thus, due to the extinction of the dodo, the tree has become endangered. So, the correct answer is 'Sideroxylon grandiflorum'.

Population of California Candor is declining due to

zoology biodiversity, classification and conservation biodiversity losses biodiversity loss and need for conservation environmental conservation and biodiversity

  1. Increasing pollution

  2. Increasing cleanliness

  3. Increasing pesticide concentration

  4. Change in surroundings

Show answer
Correct Option: A
Explanation:

The California condor is a New World vulture, the largest North American land bird. It became extinct in the wild in 1987, but the species has since been reintroduced to northern Arizona and southern Utah, the coastal mountains of central and southern California, and northern Baja California. As condors forage exclusively on dead animals, they are especially susceptible to lead exposure from carcasses which are left in the field. Lead poisoning from spent ammunition is the number one cause of death among endangered condors in the wild.

So, the correct answer is 'Increasing pollution'.

A weed, which has invaded many forest lands of India is

zoology biodiversity, classification and conservation biodiversity losses biodiversity loss and need for conservation environmental conservation and biodiversity

  1. Parthenium hysterophorus

  2. Chenopodium album

  3. Lantana camara

  4. Eichhornia crassipes

Show answer
Correct Option: C
Explanation:
Lantana camara  is a noxious weed of South American origin. It was introduced in India as garden ornamental but now it has invaded all tropical and sub tropical areas, mainly forests of India.
So, the correct answer is 'Lantana camara'.

A reflex arc does not involve

zoology control and co-ordination in plants and animals the reflex action reflex action and reflex arc basic reflex action and reflex arc

  1. A receptor

  2. A sensory pathway

  3. A motor pathway

  4. The brain

Show answer
Correct Option: D
Explanation:

A reflex arc is a simple nervous pathway and consists of the sensory receptor, afferent neuron, center, efferent neuron and effector organ. 

The afferent/sensory neurons transmit the sensory information from sensory receptors to the spinal cord (sensory pathway). The interneurons of spinal cord integrate the incoming information and signal is relayed to motor/efferent neurons.  
The motor pathway transmits the signal from motor neurons to the effector organs (muscles and glands etc). Thus, reflex arc transmits the information from receptor to effector via the spinal cord. The brain is not the part of the reflex arc. 

Movement of food in the alimentary canal involves ................... movement.

zoology control and co-ordination in plants and animals the reflex action reflex action and reflex arc basic reflex action and reflex arc

  1. Voluntary

  2. Regulatory

  3. Involuntary

  4. Digestive

Show answer
Correct Option: C
Explanation:

  • Digestion of food, contraction, and relaxation of blood vessels and many other movements are involuntary as we cannot really start or stop them simply by our will. 

Therefore, the correct answer is option C.

Spinal reflex is located in the ________

zoology control and co-ordination in plants and animals the reflex action reflex action and reflex arc basic reflex action and reflex arc

  1. Nerves

  2. Brain

  3. Epithelial lining

  4. Spinal cord

Show answer
Correct Option: D
Explanation:

  • Spinal reflex or withdrawal reflex protects the body from the damaging stimulus. 
  • It is located in the spinal cord. In this reflex pathway, more than one relay neuron connects the sensory and motor neuron.

Therefore, the correct answer is option D.

Reflex arc is a neural pathway that involves .......... nervous system. 

zoology control and co-ordination in plants and animals the reflex action reflex action and reflex arc basic reflex action and reflex arc

  1. Peripheral

  2. Autonomous

  3. Central

  4. Both A and C

Show answer
Correct Option: D
Explanation:

  • Reflex arc involves both peripheral and central nervous systems. As the route followed by nerve impulses in the production of a reflex act, is from the peripheral receptor organ, through the afferent nerve, to the central nervous system synapse, and then through the efferent nerve, to the effector organ. 

Therefore, the correct answer is option D.

Reflex arc located in the brain is called as___________

zoology control and co-ordination in plants and animals the reflex action reflex action and reflex arc basic reflex action and reflex arc

  1. Somatic reflex

  2. Cerebral reflex

  3. Autonomic reflex

  4. Both A and B

Show answer
Correct Option: B
Explanation:

  • The reflex actions which involve the brain are called as the cerebral reflex. The autonomic reflex is the one that involves inner organs and the somatic reflex is one that involves the muscles. 

Therefore, the correct answer is option B.