Biology Test - 12

Monocarpic plants flower only once in its lifetime. They die after flowering. Annuals like marigold, wheat, paddy, biennials like radish, perennials like Bambusa tulda which flowers every 50-100 years, fruits and dies.

Stamens are the male organs of a flower. Flowers maybe unisexual (either staminate or pistillate). In staminate plants only the male part, that is the stamen, is present and in the pistillate plants only the female part is present (ovaries). In bisexual plants, both are present.

Animals are categorized into 2 types of–oviparous and viviparous. Oviparous animals are those animals in which zygote development takes place outside the body. Reptiles and birds are examples of oviparous animals.

In suckers the lateral branches arise from basal and underground portions of the main stem. They grow horizontally underground and the leafy shots arise from the soil. For example, bananas.

Polycarpic plants are those that flower repeatedly, which means they do not die after flowering once. Examples are perennials like apple, mango and perennial flowers like china rose, it flowers throughout the year.

A plant having both reproductive organs in the same plant is known as monoecious plants. It may also be known as homothallic conditions. Dioecious plants are those which have only one reproductive organ, also known as unisexual plants. Another word for dioecious plants is heterothallic.

Animals are categorized into 2 types of–oviparous and viviparous. Viviparous animals are those animals in which zygote development takes place within the body itself. Mammals are a very good example for viviparous reproduction.

Tulip is an example of a bulb. It is a vegetative propagation by underground stems. They have more than one terminal buds. Another very common example is the onion. Oxalis is and example of a runner and the other 2 are examples of vegetative propagation by leaves.

There are 3 phases in a life cycle.

(i) Juvenile phase/ vegetative phase: period from birth to maturation of reproductive systems.

(ii) Reproductive phase: period when the reproductive systems have matured and ready to produce offspring.

(iii) Senescence: period when the organism starts growing old and starts degrading.

Cockroach is an example of a unisexual organism, which means it can produce only one type of gamete, either male or female. Leech, tapeworm and earthworm are bisexual organisms, organisms that can produce both gametes.