Question

Australian Marsupials and placental mammals are suitable example of adaptive radiation and convergent evolution. Explain Given reason?
class 12th CBSE Biology sample paper

Answer 1

Both adaptive radiation and convergent evolution means an organism has started its life from common pattern and have evolved because of the environment in which they got evolved.
In the same way Marsupial mammal and placental mammal belonged to same ancestor but evolved having different features because of the environment in which they are adapted to and based in the food they got!! 

Answer 2

┏─━─━─━─━∞◆∞━─━─━─━─┓
✭✮ӇЄƦЄ ƖƧ ƳƠƲƦ ƛƝƧƜЄƦ✮✭
┗─━─━─━─━∞◆∞━─━─━─━─┛

▶Marsupials are a subclass of mammal that have managed to evolve without a placenta.

♦ Australian marsupials evolve from a single ancestor & placental mammals exhibit similarities with their corresponding marsupials such as - Placental & Tasmanian wolves.

Vertebrate➫ The chordates that possess a backbone are called vertebrates.

► It is also a Subphylum Vertebrate.

➧ Characteristics are:-
▬▬▬▬▬▬▬▬▬▬▬▬▬⤵

❱ Body is bilaterally symmetrical.

❱ Body wall is triploblastic.

❱ Complex differentiation of body tissues & organs

❱ Notochord is present in the Embryo.

❱ nerve cord is divided into brain & spinal cord.

❱ Brain is enclosed in a brain box.

❱ Body is divided into head Thorax & abdomen.

❱ Body has two pairs of fins or names.

❱ Gills either present throughout life or by lungs.

➧ Subphylum Vertebrate divided into Five Classes:-
▬▬▬▬▬▬▬▬▬▬▬▬▬⤵

❶❭ Class Pisces:-
━━━━━━━━━━━━━━━━━━☟

❱ These are cold blooded.

❱ These are exclusively aquatic invertebrates.

❱ Body is streamlined.

❱ They have one pair of pectoral & pelvic fins.

❱ Respiration by 5 pairs of gills.

❱ Heart is two chambered.

❱ Skin is slimmy & covered with scales.

►Examples:- Electric Rays & DogFish

➧ Types 0f Class Pisces are:-
▬▬▬▬▬▬▬▬▬▬▬▬▬⤵

➀❭ Cartilaginous Fishes:-
━━━━━━━━━━━━━━━━━━☟

◉ Mouth is ventral.
◉ It is totally marine.
◉ Tail is heterocercal.
◉ Endoskeleton is Cartilaginous.

②❭ Bony Fishes:-
━━━━━━━━━━━━━━━━━━☟

◉ Mouth is trrminal.
◉ It is freshwater.
◉ Tail is homocercal.
◉ Endoskeleton is Bony.

❷❭ Class Amphibia:-
━━━━━━━━━━━━━━━━━━☟

❱ They are cold blooded animals.

❱ Body divided into head, trunk & Tail.

❱ Heart is three - Chambers.

❱ Fertilization is external & lay eggs.

❱ Respiration through gills, lungs & skin.

❱ They undergo hibernation & aestivation.

❱ Embryonic membrane is absent.

❱ Skin is a smooth & moist.

►Examples:- Seahorse & Catla

❸❭ Class Reptilia:-
━━━━━━━━━━━━━━━━━━☟

❱ They are cold blooded animals.

❱ Body divided into head, neck, trunk and tail.

❱ Heart is incompletely four chambered.

❱ Fertilization is internal.

❱ Respiration through gills.

❱ It is the first Terrestrial vertebrates.

❱ Embryonic  membrane is present.

❱ Skin is rough & dry.

►Examples:- Frogs & Toads
                                             
❹❭ Class Aves:-
━━━━━━━━━━━━━━━━━━☟

❱ These are warm blooded.

❱ Feathers are present on the body.

❱ Respiration by lungs with air sacs.

❱ Mammary gland is absent.

❱ They are 0viparous. Beek present.

❱ Bones are flight.

❱ Sweat & oil gland is absent.

❱ External ear is absent.

►Examples:- Crows & Parrots
                                             
❺❭ Class Mammalia:-
━━━━━━━━━━━━━━━━━━☟

❱ They are also warm blooded.

❱ Body covered with hair.

❱ Respiration by lungs without air sacs.

❱ Mammary gland is present.

❱ Teeth are present.

❱ Sweet and all gland is present.

❱ Solid bones are present.

❱ Heart is four chamber.

❱ External ears are present.

►Examples:- Humans & Rabbits

_________
Thanks...✊