Reproduction involves the formation of new life from a progenitor source, via either an asexual mechanism or a sexual mechanism

• It can involve the production of new cells (i.e. daughter cells) or entirely new organisms (i.e. offspring)
  

Asexual Reproduction

Asexual reproduction involves the division of a parent cell to form genetically identical daughter cells (clones)

• As only a single parent cell is involved, there is less of an energy cost associated with reproduction (no contribution required from another source)
  

• However, as all daughter cells are genetically identical to the parent cell, any offspring produced this way cannot contribute to an increase in biodiversity
  

The mechanism by which asexual reproduction occurs is dependent on the type of organism involved

• Asexual reproduction methods include binary fission (bacteria), budding (yeast), fragmentation (starfish), vegetative propagation (plants) and sporogenesis (certain fungi)
  

• Multicellular organisms may also regrow tissues and organs via regeneration (while this does not produce autonomous life, it is still considered a form of asexual reproduction)
  

Types of Asexual Reproduction

Sexual Reproduction

Sexual reproduction involves the formation of offspring from two separate sources (a male parent and a female parent)

• This requires the division of a parent cell to form daughter cells with only half of the genetic information (via meiosis)
  

• Sexual reproduction allows for the genetic variation in offspring required for adaptation to a changing environment

The process by which two daughter cells are fused together to form a new (and genetically distinct) parent cell is called fertilisation 

• Fertilisation can occur either internally (within a maternal host) or externally (within the open environment)

• Internal fertilisation has higher chances of success (cells are protected from environmental pressures), but exerts a survival cost on the maternal parent 

Process of Fertilisation