Ovipary – is the development of embryo inside the egg but outside the body of female. The phenomenon occurs in egg laying animals.
Vivipary – is the fertilization and development of embryo occurring inside the body of female. Placenta is present. Young ones are directly given birth. E.g. Metatherian and Eutherian mammals.
Ovovivipary – female allows the development of embryo inside the body but do not provide any other extra nourishment as the placenta is absent. E.g. shark, rattle snake, marsupials etc.
- Monoecious or bisexual or hermaphrodite – one organism consists of both sexes in it. E.g. flatworms, annelids
- Dioecious or unisexual – Each organism either male or female sex. E.g. Roundworms, arthropords etc.
- Sexual dimorphism – male and female animals can be distinguished morphologically (externally). E.g. lion &lioness, man & women etc.
- Protoandry – Male reproductive organs mature before female organs
- Protogyany – Female reproductive organs mature earlier than male ones.
In this, there is no larval stage and newly born young resembles the adult.
Young ones quite differ from adult ones and called nymphs or larvae. They lead independent life and undergo metamorphosis to become an adult.
Sinuses – cavity filled with blood
Book lung – is a primitive, leaf like & flatted type of lung found in class arachnida of phylum arthropoda. E.g. in spider, scorpion etc.
Malphagian Extretin in mosquito, coaxial glands (attached to leg and body in arthropods).