2. Mammals are very alert and active. Why ?




Дата канвертавання25.04.2016
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Mammals
1. Important characters of mammals

Presence of mammary glands , Ear pinna , 7 cervical vertebrae , Viviparity , diaphragm

2. Mammals are very alert and active.Why ?

High rate of metabolism and warm blooded nature.

3. Mammals are found throughout the earth including polar regions . Why ?

Because of their adaptations.

4.What is thecodont dentition

Teeth born in sockets of the jaws.

5. What is heterodont dentition

Four types of teeth – incisors , canines , premolars and molars.

6.What is carnassial teeth

The last premolar of the upper jaw and first molar of the lower jaw in carnivorous

Mammals work like scissors to tear flesh.

7.What is diphyodont dentition

Two sets of teeth – milk teeth and permanent teeth develop during life time.

8.In which group egg laying mammals belongs

Prototheria or monotremes.

9.In which group pouched mammals belongs

Metatheria or marsupials

10.In which group higher or placental mammals belogs.

Eutheria.

11.Name the unfinished mammals

Egg laying mammals – retaining some reptilian characters. Egs.Echdna ( spiny anteater)

And Duck billed platypus.



12.Prototheria or egglaying mammals are called living fossils and connecting links. Why?

They retain reptilian characters.


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