REPRODUCTION - ASEXUAL REPRODUCTION

REPRODUCTION

As we know, no creature on earth is immortal. organisms take birth, grow, and after a certain life span, they die.

Life span - time period between birth to natural death of an organism.

Life span of different organism - variable

Eg. Human 70-90 years

     Turtle  100-150 years

The first life on earth -- approximately 3.5 billions years ago and it exists now

Reproduction -- continuity of life on this planet.

WHAT IS REPRODUCTION?

• Reproduction is a biological process by which an organism or two organisms produce a progeny similar to it or them.

• Reproduction - continuity of species generation after generation

• Different organisms have different structures and mechanism for reproduction.
• And it is affected by physiology, anatomy, habitat of the organism.

TYPES OF REPRODUCTION

1. ASEXUAL REPRODUCTION

• Single parent
• Offspring - morphologically and genetically similar to parent and each other(clone)
• More common in microorganisms.

METHODS of ASEXUAL REPRODUCTION

1. Binary fission-

• Parent cell -- cell division -- 2 offspring
• Here, cell division = reproduction
• Eg. Amoeba, paramecium, bacteria, protists etc.

2. Multiple fission-

• Parent - divides into multiple offsprings
• Eg. Malarial parasite.

3. Budding-

• Small bud is produced from main cell body
• Initially attached to parent -- grow -- separate -- forms independent organism
• Eg. Yeast
• In multicellular organism - eg hydra

4. Spores-

• Spores are two types, asexual spores and sexual spores.

Types of spores

Depending upon locomotion

A. Zoospores -

• Motile
• Flagella for locomotion
• Most common type of spores

B. Aplanospores- 

• Non motile
• Flagella - absent

Depending upon location of spores-

A. Exospores

B. Endospores