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Asexual reproduction. OVERVIEW. Clone : an identical genetic copy of its parents Bread mold comes from a single mold spore A duplicate tree growing from the bottom of another tree Asexual Reproduction : only 1 parent is required to produce offspring .

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overview
OVERVIEW

Clone: an identical genetic copy of its parents

  • Bread mold comes from a single mold spore
  • A duplicate tree growing from the bottom of another tree

Asexual Reproduction: only 1 parent is required to produce offspring

slide4

Clones can also be created artificially (agricultural or horticultural industries, or biomedical labs)

  • Trying to create heartier breeds and increase plant production
  • Clone healthy genes to replace mutated ones
  • Potentially cloning the genes of extinct animals like Tasmanian Tigers!

We might be able to use cloning to reproduce extinct species like Tasmanian tigers!

types of asexual reproduction
Types of Asexual Reproduction

There are 5 main methods of asexual reproduction:

  • Binary Fission
  • Budding
  • Fragmentation
  • Vegetative Reproduction
  • Spore Formation
1 binary fission
1. Binary Fission
  • A single parent cell replicates its genetic material, dividing into 2 equal parts
  • Method used by small, one-celled eukaryotic organisms

like amoeba

Ex.: Amoebas

  • Have between 30-40

chromosomes

  • Chromosomes duplicated during

mitosis

slide8

Binary fission is the onlymethod

of reproduction for some bacteria!

  • No nucleus = no mitosis!

Instead, one ring of DNA is

replicated...

  • Under ideal conditions, it can

replicate every 20 min.

Ex. Streptococcus bacteria

slide9

Mutations can occur

during binary fission!

  • Mutations in the DNA

of bacteria can make

it very resistance to

antibiotics

2 budding
2. Budding
  • Areas of an individual undergo mitosis and cell division, developing into an identical organism
  • Used by some multicellular organisms (hydras and sponges) that only have a few different cell types
  • The “buds” might detach from the parent and become a new individual OR remain attached
slide11

1. Hydra develops a “bud”

2. The bud develops a

mouth and tentacles

3. When it’s fully formed

the daughter hydra

detaches from parent

4. The daughter is fully

independent

slide12

Budding is great for organisms like sponges because they attach to rocks and move very little. Colonies can grow in the same area or break off and colonize new locations.

3 fragmentation
3. Fragmentation
  • Occurs when a piece of an organism breaks apart (ex. injury) and each fragment develops into a clone of the parent

Ex.: Starfish

  • If a broken arm contains enough DNA it can develop into an identical copy
slide14

Plants can also reproduce by fragmentation IF the environment doesn’t change and

IF there are enough

nutrients available.

Example: Eurasian milfoil

  • Introduced to North America
  • Chopped up by propellers and spread through lakes
4 vegetative reproduction
4. Vegetative Reproduction
  • Occurs when special cells (usually in plant stems and roots) divide repeatedly to form structures that will eventually develop into an identical plant
    • Develop off of the bulb

or as sprouts (“eyes”)

Ex.: Tulips, daffodils,

hyacinth bulbs, and

potatoes

slide16

Disadvantage

  • Daughter plants grow very close to parent plants
  • Will complete for soil, nutrients, and light
benefits of vegetative reproduction
Benefits of Vegetative Reproduction

Potatoes

  • #1 tuber crop in world
  • Used globally

Common Camas

  • An important part of the First Nations diet
  • Also used for trading
human assisted methods of vegetative reproduction
Human Assisted Methods of Vegetative Reproduction
  • CUTTINGS
  • The plant grower removes a part of the stem (or leaf/root) and plants the cutting in a special growing medium
  • Plant hormones, which are chemical messengers, are often applied to the cut stem
    • Hormones signal nuclei to stimulate cell division, causing some cells to develop into root tissue
  • House plants can reproduce in this method
slide20

2. GRAFTING

  • Stems called “scions” are attached to the rotted stock (“rootstock”) of a similar plant
  • Often used for apple trees and rose plants
  • Another form called “budding” is used to grow apple trees
slide21

Advantages:

  • Can help scion benefit from a more rigorous root

system

  • Produce fruit

within 2-3 years

instead of 5-10

years

  • Helps control

eventual size of

plant

5 spore formation
5. SPORE FORMATION
  • Method used by some bacteria, micro-organisms, fungi (ex. bread mold), mosses, and ferns
  • Reproduction through the formation of single-celled spores
  • Spores: a reproductive cell that grows into a new individual by mitosis
    • Very light in weight
    • Rely on wind or water for

transportation

slide23

If conditions are right (enough moisture and food, and proper temperature) a new individual will grow wherever it lands

  • Many spores have tough outer coatings that allow them to survive in harsh conditions (drought or extreme temp.) until the conditions are right