6.4.1 natural clones

Question 1

define clones

Answer 1

genetically identical organisms or cells

Question 2

vegetative propagation

Answer 2

reproduction from vegetative parts of plant - usually over-wintering organ

Question 3

how are clones produced

Answer 3

= asexual reproduction

1. nucleus divided by mitosis
2. mitosis creates 2 identical copies of DNA
3. separated into 2 genetically identical nuclei
4. cell divides forming 2 genetically identical cells

Question 4

advantages of natural cloning

Answer 4

• if growth conditions are good for parent, they will be good for offspring
• cloning is relatively rapid so population can increase quickly
• reproduction can be carried out even if 1 parent & sexual reproduction isn’t possible

Question 5

disadvantages of natural cloning

Answer 5

• offspring may become overcrowded
• no genetic diversity (other than potential mutation during DNA replication)
• population shows little variation
• selection isn’t possible
• if environment becomes less advantageous, whole population is susceptible

Question 6

name examples of vegetative propagation (process involved in natural cloning for plants)

Answer 6

• runners
• stolons
• rhizomes
• suckers
• bulbs
• corms
• leaves
• tubers

Question 7

describe runners and stolons

Answer 7

• plants grow horizontal stems which can form roots at certain points
• grow on surface of ground

Question 8

describe rhizomes

Answer 8

• plants grow horizontal stems which can form roots at certain points
• grow underground
• some adapted as thickened over-wintering organs from which 1+ new stems will grow in spring

Question 9

describe suckers

Answer 9

• new stems that grow from roots of plant
• may be close to base of older stem or far away
• original horizontal branch may die, leaving new stem as separate individual

Question 10

describe bulbs

Answer 10

(eg. onions)
- over-wintering mechanism for many perennial monocotyledonous plants
- consist of underground stem from which grows series of fleshy leaf bases
- also an apical bud = grows into new plant in spring
- often contains 1+ apical bud

Question 11

describe corms

Answer 11

• solid (not fleshy like a bulb)
• underground stem with scaly leaves & buds
• remain in ground during winter
• in spring, buds grow producing 1+ plants
  (eg. taro)

Question 12

describe leaves

Answer 12

• kalanchoe plant reproduces asexually, as clones grow on leaf margins
• immature plants drop off leaf & take root

Question 13

describe tubers

Answer 13

(eg. potatoes)
- another type of underground stem
- one potato will grow into 1+ plants
- each new plant can produce many new tubers (potatoes) later that year

Question 14

example of natural animal cloning

Answer 14

1. identical twins
   - occurs when fertilised egg (zygote) divides as normal but 2 daughter cells split becoming 2 separate cells
   - each cell grows & develops into new individual
2. water flea & greenfly reproduce asexually producing clones