Forelimbs of cat, lizard used in walking; forelimbs of whale used in swimming and forelimbs of bats used in flying are an example of:
1. Analogous organs
2. Adaptive radiation
3. Homologous organs
4. Convergent evolution
Variation in gene frequencies within populations can occur by chance rather than by natural selection.
This is referred to as:
1. Genetic drift
2. Random mating
3. Genetic load
4. Genetic flow
1. Shortening of jaws
2. Binocular vision
3. Increasing brain capacity
4. Upright posture
In the case of peppered moth (Biston betularia), the black-coloured form became dominant over the light-coloured form in England during the industrial revolution. This is an example of:
1. | natural selection, whereby the darker forms were selected |
2. | appearance of the darker coloured individuals due to very poor sunlight |
3. | protective mimicry |
4. | inheritance of darker colour character acquired due to the darker environment |
Select the correct statement from the following:
1. | Darwin variations are small and directionless |
2. | fitness is the end result of the ability to adapt and gets selected by nature |
3. | all mammals except whales and have seven cervical vertebrae |
4. | Mutations are random and directional |
The finches of the Galapagos islands provide evidence in favour of:
1. special creation
2. evolution due to mutation
3. retrogressive evolution
4. biogeographical evolution
An important evidence in favour of organic evolution is the occurrence of:
1. homologous and vestigial organs
2. analogous and vestigial organs
3. homologous organ only
4. analogous organ only
Variations caused by mutation, as proposed by Hugo de Vries, are:
1. | small and directionless | 2. | random and directional |
3. | random and directionless | 4. | small and directional |
In a species, the weight of a newborn ranges from 2 to 5 kg. 97% of the newborns with an average weight between 3 to 3.3 kg survive whereas 99% of the infants born with weights from 2 to 2.5 kg or 4.5 kg to 5 kg die. Which type of selection process is taking place?
1. | Cyclical selection | 2. | Directional selection |
3. | Stabilizing selection | 4. | Disruptive selection |
For the stability of the organic compounds, Oparin opined that probably:
1. UV radiation never reached the surface of the primeval Earth
2. the primitive Earth was in a molten state
3. the primitive Earth atmosphere was reducing rather than oxidizing
4. plenty of energy sources were available for chemical reactions to occur