Topic 3 – Passing it on – PART 1 – ASEXUAL REPRODUCTION
Learning Outcomes:
When you have completed this topic you will be able to:
- Distinguish between sexual and asexual reproduction and indentify and
interpret examples of asexual and sexual reproduction in different species
by:
- - describing representative types of asexual reproduction
- - describing representative types of sexual reproduction
- - describing examples of organisms that show both sexual and asexual
reproduction
- - describing the formation of a zygote and embryo in plant and animal
reproduction
- Compare sexual and asexual reproduction, in terms of the advantages
and disadvantages.
VOCABULARY: Asexual reproduction, binary fission, spores, zoospores, meristem, clones,
budding, zygospores, bacterial conjugation, zygote, pistil, stamen, ovule, pollen tube,
embryo, cotyledons, sexual reproduction, gamete, internal fertilization, external fertilization.
•
Everywhere you look, there are examples of organisms that look just like their parents.
– How does this happen???
Reproduction
•
Is ONE of the characteristics of living things
•
Is ESSENTIAL to the survival of the SPECIES but NOT the INDIVIDUAL
•
Reproduction can be either sexual or asexual
How are traits passed on?
•
_______________________________ are said to be inherited or
_________________________________ and are passed on in the genetic material (DNA)
Asexual reproduction
• DEFINITION:
•
______________________________________________ occurs when only one parent supplies
the information to the offspring
– A formation of a new individual from a SINGLE organism
• OFFSPRING LOOKS LIKE:
•
Inherited traits are like the parents
– Looks IDENTICAL to the parent
• ORGANISM EXAMPLES:
•
Common among bacteria and fungi
ADVANTAGES OF ASEXUAL REPRODUCTION:
-
DISADVANTAGES OF ASEXUAL REPRODUCTION:
Types of Asexual Reproduction:
1. Binary Fission
a. Many one celled organisms such as the amoeba reproduce asexually by binary
fission.
b. _______________________________: the first cell duplicates its organelles and then
splits creating a second organism with a copy of the same genetic material
2. Asexual Spores
a. Some fungi and mushrooms can reproduce asexually using
_________________________.
b. Spores are single celled, reproductive structures
c. Usually spores are produced in high numbers to ensure at least some survive
d. Some other algae produce ___________________________ which move with a taillike structure called a flagella
3. Budding
a. In budding, an organism will grow a new group of cells near its base (BUD) and
then the __________________ detaches the new growth to start a new organism
b. Examples: Sea sponge
Plants don’t produce spores, but they still reproduce asexually.
4. Meristem
a. ______________________________________
i. ________________________________ are able to repair damage to the plants
ii. Meristem cells are also used for ‘cuttings’ when planting new plants.
5. Runners and suckers
a. ________________________ are sent out by strawberry plants above ground
b. _________________ are sent out by poplar trees and lilacs above or below ground
6. Tubers
a. Potatoes and yams
b. When they are put into the ground they will grow a new plant
7. Bulbs
a. Onions and daffodils
b. When put into the ground they will grow a new plant
Asexual Plants – CLONES?
•
In asexual reproduction in plants, the offspring are ________________________ (exact
copies) of the parent.
– You may recall Dolly the sheep. She was the first organism to be successfully
cloned.