Organisms and Populations Test - 10

Neutralism is a kind of relationship in which different organisms live in same habitat but do not harm each other. Shrew, rat and rabbit lives in same grassland but do not compete for food and shelter.

Allen’s rule says that the body shapes and proportions of endotherms vary by climatic temperatureby either minimizing exposed surface area in cold climates or maximizing exposed surface area to maximize heat loss. So, mammals from colder climates generally have shorter ears and limbs

Echolocation is the use of sound waves and echoes to determine where objects in space. Bats use echolocation to navigate and find food in dark.

Gambusia fish eats mosquito larvae that control the population of mosquito without using any chemicals. So this mosquito fish is used in biological control of mosquito.

Eudynamys or Koel laying eggs in nest of crow is an example of social parasitism. Crow rears the egg of koel using their labour and time without any benefit so, it is a social parasitism.

Xerophytes are plants that grows in deserts having very less water. Sunken stomata, leaves reduced into spines and CAM photosysnthesis are the characteristicfeatures of these plants. Cuticle is present on leaves to prevent loss of water.

The body temperature of any homeotherm falls or rises suddenly it would become ill due to change in homeostasis of individual. At higher temperature enzymatic activity get altered that change the physiological activities of organisms.

Vital index is the ratio of births to deaths within a population during given time. If vital index is greater than hundred then the population will decreasing showing negative growth.

Human population growth curve is S-shaped in which at initial stage growth is slow followed by exponential growth and finally again start declining to follow sigmoid curve growth.

Natality or birth rate is the number of birth in a given period in the population that are added to initial population. Actual birth rate under environmental condition is much less than total birth because all organisms do not survive adulthood due ot predation, completion etc.