Question

The egg of an elephant is:
(a) Macrolecithal and Centrolecithal
(b) Microlecithal and Telolecithal
(c) Mesolecithal and Homolecithal
(d) Microlecithal and Isolecithal

Answer 1

This is related to the amount of yolk present in the egg and also the distribution of yolk in the cytoplasm. Here the amount of yolk present is less with its even distribution in the cytoplasm. This is found in the organism belonging to the class Mammalia.

Complete answer:
The egg of an elephant is Microlecithal and Isolecithal. Micro means less or little and lecithal means yolk so in the egg of an elephant the amount of yolk present in the ova is very less and also it is evenly distributed in the cytoplasm of the egg. The equal distribution of yolk means it has two equal hemispheres of yolk. The egg is fertilized and the development of the embryo occurs inside the individual's body. In this type of egg four major types of cleavage are observed, these are radial holoblastic, spiral holoblastic, bilateral holoblastic, and rotational holoblastic.
- On reaching puberty, the male elephant leaves their family groups and lives alone with other males.
- The adults seek the family groups to interact with and for mating. They gain dominance with the help of increased testosterone and aggression which is known as musth. They communicate through touch, sight smell, and sound by using infrasound and seismic communication over long distances.
- Macrolecithal eggs are eggs with a large amount of yolk present in it. This type of egg is commonly found in myxinidae, Elasmobranchii, Teleostei, Chelonia, Sauria, serpents, Crocodilia, aves, and Monotremata.
- Centrolecithal: The term centrolecithal means the placement of yolk is in the center of the cytoplasm of the ova.
-Telolecithal: The term telolecithal means the uneven distribution of yolk in the cytoplasm of ova. The yolk is concentrated at one pole of the egg. This type of egg is commonly found in birds, reptiles, fish, and monotremes.
- Mesolecithal: Mesolecithal eggs are eggs having an intermediate size of yolk that is strongly concentrated in one hemisphere. Commonly found in petromyzontidae, Acipenseridae, amiidae, lepidosirenidae, and amphibia.
- Homolecithal: Homolecithal eggs are eggs having a small amount of yolk that is fairly uniformly distributed throughout the cytoplasm of the ova. This type of egg is commonly found in the sea urchin, amphioxus, tunicates, and mammals.

So, the correct answer is, 'Microlecithal and Isolecithal'.

Note:
- The egg of an elephant contains a very small amount of yolk.
- An elephant's egg yolk is evenly distributed in the cytoplasm of the ova.
- The eggs of the elephant weigh about 10 kilograms and the volume of the egg is around 160 times greater than that of an egg of a chicken.