Advantage & Disadvantage EXTERNAL FERTILISATION INTERNAL FERTILISATION ADVANTAGE -rapid & prolific (large numbers of gametes - fish can release between 2.5 million to 300 million EGGS / year depending on the species of fish) - females can continuously produce eggs - high number of zygotes -not a lot of energy required especially once eggs & sperm released - young are widely dispersed reducing the competition with parents for available resources - less gametes required ie especially for females (1 to 2 eggs) -can occur on on land or in water -greater success rate as gametes closer together - low number of zygotes required as fertilisation guaranteed - protected from predators & disease -developed young cared for to ensure maximum survival - overall survival rate HIGH DISADVANTAGE - large numbers of gametes required to ensure some are fertilised - no control once the gametes released - gametes on their own - must have an AQUATIC environment - ocean, rivers or lakes - susceptible to large number of predators & this can greatly affect survival numbers - overall survival rate LOW - males release on average 80300 million sperm/ejaculation to ensure some survive the journey through the female reproductive system - complex mating rituals -energetically very costly - limited offspring means high level of care to ensure maximum survival
