Biology Test - 13

The general term for the period of growth is known as juvenile phase. In plants it is known as the vegetative phase. The end of juvenile phase marks the beginning of reproductive phase.

Bulbils, also called vegetative propagation by flower buds is not an example of sub aerial vegetative propagation. It produces multicellular fleshy buds that give rise to new plants. Example, Agave.

Sexual reproduction is the fusion of the male and the female gamete that forms a single celled zygote, the process is known as fertilization. This process has been divided into 3 events. The pre-fertilization, fertilization and post-fertilization events.

All heterogametic species can produce 2 types of gametes, male and female, their sex chromosomes are unidentical. Homogametic species the sex chromosomes are identical.

Since zygote development takes place inside the female body, they are in a protected environment. Unlike the oviparous animals, which are vulnerable. The chances of oviparous animals to survive is low.

Starfish reproduces by binary fission. Just like the single celled organisms, starfish breaks along the central axis. The 2 separate halves then lead an independent life by forming or regenerating the limbs and missing parts.

Hormones are chemical messengers that travel through the bloodstream (in case of animals). Hormones are responsible for the change in the phases in both plants and animals. Hormonal change can be affected by environmental factors too.

Meiocytes are cells in diploid organisms that undergo meiosis. Meiosis is the process of producing 4 haploid cells from a single cell that has been divided twice. The haploid cell then becomes diploid after its fusion with the other sex gamete.

In flowering plants, the zygote is formed in the ovule. The pollen tube is a mode of transportation for the pollens that lay on the stigma, to the ovaries. Anther consists of pollen grains (male gamete).

Parthenogenesis is a process of reproduction where the ovum is unfertilized. In case of bees the eggs are haploid which subsequently makes the male bee haploid. It is a type of asexual reproduction. This type of reproduction takes place in lower plants like aphids.