Question

‘Different species use different strategies to determine the sex of a newborn individual. It can be environmental cues or genetically determined’. Explain the statement by giving examples for each strategy.

Answer 1

Hint: Sex determination can be defined as a biological system in which the development of sexual characteristics of an organism can be determined. The set of chromosomes inherited by the offspring from their parents are responsible for its sexual identity. In addition to it, sex can be determined based on the environment and depending on the genetic composition.

Complete step by step answer: A biological system that determines the development of sexual characteristics in an organism is called sex determination. Organisms that are produced by sexual reproduction have two sexes. types of sex determination in organisms include environmental-based sex determination and genetic-based sex determination. Human beings are examples in which determination is based on genetic composition. Here, males and females have different alleles or even different genes which specify their sexual morphology. In animals, it is based on the differences in chromosomes. Various combinations of chromosomes are XY, ZW, XO, ZO, and haplodiploidy. In humans, males consist of XY chromosomes, and females consist of XX chromosomes. Depending on which chromosome is inherited by the father the sex of the offspring is determined. If the X chromosome is inherited it results in the production of a daughter and if a Y chromosome is inherited it results in the formation of a son with XY chromosome and one X chromosome is inherited from the mother. The sex of foetus is determined by an environmental variable such as temperature in some species. For example, the incubation temperature before hatching determines the sex of an organism. high incubation temperature results in male offspring in lizards.

Note: Location-dependent determination systems as seen in the marine worm which is also an environmental sex-determination system. For example, in Bonellia viridis if they make physical contact with a female, male larvae are formed and if they end up on the bare seafloor female larvae is produced.