Living organisms display a wide variety of methods or reproductive strategies for passing on their genetic information to their offspring Asexual Reproduction Involves only one parent Offspring are identical ID: 784779
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Slide1
Passing it On
Unit A: Topic 3
Slide2Living organisms display a
wide variety of methods or reproductive strategies for passing on their genetic information to their offspring.
Slide3Asexual Reproduction
Involves only one parentOffspring are identical
to the parent
Four
main types of asexual reproduction are:
Binary fission
Budding
Spore Production
Vegetative Reproduction
Slide4Binary Fission
Occurs in unicellular organisms
Cell splits in
two
producing
identical offspring
Example
s: Bacteria and
protists
https://www.youtube.com/watch?v=DY9DNWcqxI4
https://www.youtube.com/watch?v=
X7Qz9oc4DsA
Slide5Slide6Budding
Parent produces a small, attached (identical) version of itself.The offspring can stay
connected or detached
Examples
: Coral, yeast, hydra.
http://www.youtube.com/watch?v=489CSop00sY
Slide7Slide8Spore Production
Similar to seeds
Produced by the division of parent cells.
Examples: Fungi, ferns, moulds, and algae.
Many spores are produced to ensure some survival.
Some fungi and algae produce
zoospores
which move with a tail-like flagella
http://www.youtube.com/watch?v=eZ40LDWt678&feature=related
Slide9Vegetative Reproduction
There are many different types including runners, tubers and suckers
.
Examples: Strawberry plants, potatoes, and aspen trees.
http://www.youtube.com/watch?v=fPraEesXRSs
Slide10Asexual Reproduction
Asexual reproduction can also happen without special cells.
In the
meristem
of plants, found in the tips of roots and stems, cells rapidly divide.
Cutting from a parent stem
may be used to produce new
plants that
clones
(exact copies)
if that stem is planted.
http://www.youtube.com/watch?v=ZLGz-Ykzxqo
Slide11pedicel
pollen grains
Slide12Sexual Reproduction in plants
Slide13Sexual Reproduction in plants
Most plants will produce both male and female gametes in one plant, but some only produce male
or
female gametes.
Pollen
, which is found on the
stamen
, has the
male gametes
in it.
Ovules
, which are found on the
pistil
, contain the
female gametes
.
Slide14Pollen
Self-Pollination: when the pollen from the anther is transferred to the stigma.
Cross-pollination
: when the pollen from one plant is carried to a different plant.
How
can pollination occur?
Wind, water, animals/birds
Slide15Fertilization
Fertilization: When the gametes in the pollen join with the gametes in the ovum (on the same plant).
Cross-fertilization
: When the pollen from one plant fertilizes another plant.
http://www.youtube.com/watch?v=KMQtLWpAdXI&feature=related
Slide16Sexual Reproduction in plants
http://www.teachersdomain.org/asset/oer08_vid_flowers
Pollen grains
, each of which contains a
sperm
nucleus, are brought to the female
eggs
in the
ovaries
.
The pollen grain grows an extension called a
pollen tube
. This pollen tube grows until it reaches the ovule.
The
sperm
nucleus travels down the tube to fertilize the egg.
A
zygote
is formed and contains the genetic information from both parents.
It then goes through many cell divisions to form a multicellular
embryo
containing miniature leaf, root, and stem.
The embryo is
protected by a seed
and can
stay dormant
for a long time.
Slide17Sexual Reproduction in animals
Involves specialized sex cells called gametes
Fertilization
– the union of sperm and egg
Slide18Sexual Reproduction in animals
http://www.youtube.com/watch?v=UgT5rUQ9EmQ&feature=related
Fertilization can occur
internally
or
externally.
Internal fertilization
occurs in insects, reptiles, birds, mammals, some fish and amphibians.
Results in a high rate of success because egg cells are protected.
External fertilization
occurs in sponges, most worms, many fish and amphibians.
Results in a low rate of success because egg cells are exposed to harsh climates and predators.
Slide19Sexual Reproduction in Bacteria
Bacterial Conjugation
A
connection forms between two
cells.
Genetic material is transferred
directly from one cell to another
Cells will
then go through binary fission
to create more cells
http://www.youtube.com/watch?v=O-EdX4MaMFE&feature=fvwrel
Slide20Asexual Reproduction
Advantages
Only need
one
organism
Doesn’t require
any specialized cells to bring gametes together
Can
produce lots
very quickly
Disadvantages
If conditions are unfavourable, the entire population could be wiped out.
Slide21Sexual Reproduction
Advantages
Provides lots of
variation
which helps species survive environmental change
Disadvantages
Perfect timing and conditions are required
Two partners
are needed
Takes lots of
energy
Only produces
limited offspring
Slide22What are some organisms that reproduce
both sexually and asexually?
Some species of grasses
Sunflowers
Roses
Aphids
Sponges
Fungi – some types of fungi can produce asexually by using spores, but they can also produce sexually by using
zygospores
.
Zygospores
contain genetic information from two different sources.
Slide23Review Assignment
What is a zygote and how is it formed?
List three examples of asexual reproduction.
List three ways pollination can occur.
What is similar about sperm and egg cells? What is different?
List the steps of fertilization and embryo development in animal sexual reproduction.
List the steps of fertilization and embryo development in plant sexual reproduction.