Chapter-9. Heredity and Evolution SCIENCE class 10 in english Medium CBSE Notes

1. Homologous Organs: Those organs in the various organisms which have same structure and origin and different functions are called homologous organs. 

Example : Fore limb of frogs, feather of birds, Fore limb of horse are same originated but have difference functions. 

2. Analogous Organs: Those organs of various organisms which have same function and but have different in oriigin are called analogous organs. 

Example : wings of butterfly and wings of birds have same functions but differ in origin.

3. Fossils: The preservative traces of dead organnisms are called fossils. 

Example: If a dead insect gets caught in hot mud, for example, it will
not decompose quickly, and the mud will eventually harden and retain
the impression of the body parts of the insect. 

Some Examples of obtain fossils: 

(1) Fossil - tree trunk

(2) Fossil - invertebrate (Ammonite)

(3) Fossil - invertibrate (Trilobite)

(4) Fossil - fish (Knightia)

(5) Fossil - dinosaur skull (Rajasaurus)

Fossils also provide evidence