BIO2242 – lecture 15
What is reproduction:
The process at which animals go off to produce offsprings. It is the core goal or
focus of life. Natural selection works quite intensely on reproductive strategies.
Modes of animal reproduction:
Absence of sex.
Haploid gametes fusing to form a diploid zygote (Agametic)
Gametes are formed but they are not fertilized (Parthenogenesis)
Why be asexual:
Much better at producing a lot of offsprings quickly.
What animals can be asexual:
Genetic imprinting = tell whether genes are from mother or father
Does not involve the fusion of haploid gametes
Is energetically expensive as it requires searching for a male
Is common in birds and mammals
Does not facilitate the rapid spread of successful genotypes
Agametic reproduction: Fission:
Where parent individual splits into two (fission). The two daughter are equal in
size. It is equivalent to cell division.
Agametic reproduction: Budding:
You get an outgrowth of the parent individual where it buds off and forms its
own individual. Through this process, the offspring is smaller in size than the
Agametic reproduction: Fragmentation:
Splice and dice body parts where they regenerate into complete individuals – not
always, but they can.
Where new individuals regenerate from fragments of the parent
A form of asexual reproduction where the parent and offspring are equal in size
Where new individuals arise from outgrowths in existing ones
Common in vertebrates
It is extremely rare in nature.
Advantage = When there’s no males around the females, they can still reproduce.
In good conditions, it can reprodu