CollingwoodScience 9

5.2 and 6.2 Sexual Reproduction vs Asexual Reproduction Name:

Date:

What is Asexual reproduction?

·  Requires only ONE parent to produce offspring.

·  Produces offspring IDENTICAL to the parent and to each other (clones).

·  Produce LARGE numbers of offspring to ensure survival

o  e.g. bread mould and tree shoots (natural)

o  e.g. plant, animals, tissues and genes (artificial)

What are the forms of Asexual Reproduction?

1.  Binary Fission (e.g. Ameoba)

2.  Budding (e.g. Hydra, Yeast)

3.  Fragmentation (e.g. seastar)

4.  Vegetative reproduction (e.g. strawberries send out ‘runners’ away from plant)


What is Sexual reproduction?

·  Requires TWO parents to produce offspring

·  Produces offspring that are NON-IDENTICAL to the parent and each other

o  (brings NON - identical gametes together to form a new organism)

·  Genetic Variation maintained

2 types of Fertilization:

1.  External Fertilization

a.  sperm and egg combine OUTSIDE parents

b.  e.g. Sea Urchins, Fish, Mosses

2.  Internal Fertilization

a.  sperm and egg join INSIDE the female’s body

i.  e.g. humans, mammals

b.  Advantages:

i.  Embryo PROTECTED from predators

ii. Offspring more likely to SURVIVE as many species will PROTECT them while they mature

c.  Disadvantages:

i.  Much more ENERGY required to find mate

ii. Fewer ZYGOTES produced, resulting in LESS offspring

iii.  More ENERGY required to raise and care for offspring

Advantages / Disadvantages
Sexual Reproduction / ·  Genetic variability maintained
·  Increases chance of organism’s survival
·  Facilitates adaptation
·  ‘Speeds’ up evolution / ·  Lots of energy is spent
·  Courtship is time / resource consuming
·  Time to raise offspring
·  Resources to raise offspring
Asexual Reproduction / ·  Large numbers of offspring reproduce very quickly
·  Large colonies can out-compete other organisms for nutrients and water
·  Species can survive if the number of predators increases
·  Courtship is a non-issue
·  Save energy / ·  Offspring compete for food and space
·  Extreme temperatures can wipe out entire colonies
·  Negative mutations can destroy many offspring
·  Adaptation to environments is difficult
·  Slows evolution