abbotts. topics advantages and disadvantages of asexual reproduction advantages and disadvantages of...

Download ABBOTTS. TOPICS Advantages and disadvantages of asexual reproduction Advantages and disadvantages of sexual reproduction Advantages and disadvantages

Post on 25-Dec-2015

237 views

Category:

Documents

0 download

Embed Size (px)

TRANSCRIPT

  • Slide 1
  • ABBOTTS
  • Slide 2
  • TOPICS Advantages and disadvantages of asexual reproduction Advantages and disadvantages of sexual reproduction Advantages and disadvantages of asexual reproduction Advantages and disadvantages of sexual reproduction
  • Slide 3
  • PLANT REPRODUCTION Is the ability of living organisms to produce a new generation of themselves Important for survival and evolution of a species Is the ability of living organisms to produce a new generation of themselves Important for survival and evolution of a species
  • Slide 4
  • TYPES OF REPRODUCTION
  • Slide 5
  • Slide 6
  • ASEXUAL REPRODUCTION Also called vegetative propagation Production of a new generation of the same species by one parent Takes place by mitosis All new organisms are genetically identical to their parents and to each other Such organisms are called clones
  • Slide 7
  • VEGETATIVE REPRODUCTION STEMS
  • Slide 8
  • STOLON Long thin stems that go across the ground Chlorophytum
  • Slide 9
  • VEGETATIVE REPRODUCTION STEMS
  • Slide 10
  • VEGETATIVE REPRODUCTION STEMS
  • Slide 11
  • VEGETATIVE REPRODUCTION
  • Slide 12
  • ROOTS Suckers develop from Roots and grow into new plants
  • Slide 13
  • VEGETATIVE REPRODUCTION Root tubers are swollen roots E.g. dahlia ROOTS
  • Slide 14
  • VEGETATIVE REPRODUCTION New plants can develop directly from leaves Eg Streptocarpus spp. LEAVES Streptocarpus leaf cuttings
  • Slide 15
  • ARTIFICIAL VEGETATIVE REPRODUCTION
  • Slide 16
  • ADVANTAGES OF ASEXUAL REPRODUCTION Only one parent needed and all individuals can produce offspring No special organs of reproduction are required (eg flowers) The process is simple and fast only mitosis involved No outside agents such as pollinators are needed Little energy is used (do not have to produce reproductive organs) Only one parent needed and all individuals can produce offspring No special organs of reproduction are required (eg flowers) The process is simple and fast only mitosis involved No outside agents such as pollinators are needed Little energy is used (do not have to produce reproductive organs)
  • Slide 17
  • ADVANTAGES OF ASEXUAL REPRODUCTION New plants are genetically identical No variation Successful varieties are maintained Will be the same year after year good for commercial crops Eg potatoes and strawberries New plants are genetically identical No variation Successful varieties are maintained Will be the same year after year good for commercial crops Eg potatoes and strawberries
  • Slide 18
  • ADVANTAGES OF ASEXUAL REPRODUCTION Asexual reproduction is useful in stable conditions If the parent is well adapted to a particular environment the offspring also will be A favourable mutation can spread rapidly, enabling a population to adapt quickly to any new environmental conditions Asexual reproduction is useful in stable conditions If the parent is well adapted to a particular environment the offspring also will be A favourable mutation can spread rapidly, enabling a population to adapt quickly to any new environmental conditions Mutation = change in a chromosome resulting in a new characteristic
  • Slide 19
  • ADVANTAGES OF ASEXUAL REPRODUCTION By avoiding seed dormancy, plants can be propogated throughout the year independent of seasonal changes Germination after seed dormancy Germination dormancy
  • Slide 20
  • DISADVANTAGES OF ASEXUAL REPRODUCTION No variation no chance of improving the quality of the species Overcrowding may occur and resources such as food might be in short supply Genetic weaknesses cannot be bred out Infectious diseases (caused by viruses) are likely to be passed on to the new crop No variation no chance of improving the quality of the species Overcrowding may occur and resources such as food might be in short supply Genetic weaknesses cannot be bred out Infectious diseases (caused by viruses) are likely to be passed on to the new crop Overcrowded basil No variation
  • Slide 21
  • SEXUAL REPRODUCTION IN PLANTS Is the production of a new generation by bringing together the genetic material of two parents The offspring will therefore be genetically different from the parents
  • Slide 22
  • PROCESS OF SEXUAL REPRODUCTION IN PLANTS Diagram Parents produce gametes in sex organs Male and femae gametes are brought close together by pollination Male and female gametes fuse (fertilisation) Zygote grows into a new plant
  • Slide 23
  • ADVANTAGES OF SEXUAL REPRODUCTION Results in variation which: Is the basis of evolution Gives organisms a better chance of survival in an unstable environment as the offspring may be able to adapt to the new conditions May prevent the spread of disease as the offspring might be genetically resistant to a particular disease Can result in the quick elimination of harmful mutations Results in variation which: Is the basis of evolution Gives organisms a better chance of survival in an unstable environment as the offspring may be able to adapt to the new conditions May prevent the spread of disease as the offspring might be genetically resistant to a particular disease Can result in the quick elimination of harmful mutations Mutation = change in a chromosome resulting in a new characteristic
  • Slide 24
  • ADVANTAGES OF SEXUAL REPRODUCTION Seeds are usually dispersed widely which gives them more space and nutrients
  • Slide 25
  • Slide 26
  • Slide 27
  • Drosera cistiflora is a plant with a wide range of floral colour variations and many of these can be observed in fynbos and renosterveld habitats during spring. Flowers vary in size and colour.
  • Slide 28
  • DISVANTAGES OF SEXUAL REPRODUCTION There is a high expenditure of energy In plants special organs of reproduction need to be produced e.g. flowers The reproduction process is slow Unfavourable mutations and recessive genes might be passed on to the offspring Outside agents might be needed in plants to carry pollen or seeds There is a high expenditure of energy In plants special organs of reproduction need to be produced e.g. flowers The reproduction process is slow Unfavourable mutations and recessive genes might be passed on to the offspring Outside agents might be needed in plants to carry pollen or seeds
  • Slide 29
  • CHARACTERISTICSASEXUAL REPRODUCTION SEXUAL REPRODUCTION Number of parentsOneTwo Reproductive organsLeaves, roots and stemsflowers Rate of processFaster (no gamete formation or pollination) Slower (gamete formation or pollination) Outside agentsNone neededOutside pollinators often need Energy inputlowHigh energy is needed to make flowers Ability to adapt to environment No if environment changes, organisms die Yes offspring adapt to the changing environment and survive Possibility of evoultionLow no genetic variation Good genetic variation When is the method an advantage In a stable environmentIn an unstable environment organisms can adapt HOW DO ASEXUAL AND SEXUAL REPRODUCTION COMPARE
  • Slide 30
  • THE END

Recommended

View more >