16.1 - 16.3 Reproduction in plants Flashcards
asexual reproduction
a process of resulting in the production of genetically identical offspring from one parent
binary fission
when bacteria produce exact genetic copies of themselves in a type of asexual reproduction
state and explain types of asexual reproduction in plants
- Bulbs and tubers - these are food storage organs from whcih budding can occur and produce new plants that are genetically identical to parent plant
- Runners - some plants grow shoots that contain tiny plantelets on them (e.g. strawberries). These will grow roots and develop into seperate plants that are genetically identical to parent plant.
Advantages of ASEXUAL reproduction
- pop can be increased rapidly when conditions are right
- can exploit suitable environments quickly
- more time and energy efficient
- reproduction is completed much faster than sexual
Disadvantages of ASEXUAL repoduction
- Limited genetic variation in pop
- pop is vulnerable to changes in conditions - only suited for one habitat
- disease more likely to affect the whole pop bcs no genetic variation
Advantages and Disadvantages of ASEXUAL reproduction for CROPS
+) varieties with useful features can be cloned in large numbers
-) all clone plants are susceptible to the same disease
Sexual reproduction
a process involving the fusion of the nuclei of two gametes to form a zygote and the production of genetically different offspring
fertilisation
fusion of the nuclei of gametes
whats special about the nuclei of gametes?
they are haploid nuclei - contains only one set of chromosomes (23, no pairs)
Advantages of SEXUAL reproduction
- Increases genetic variation
- species can adapt to new environment bcs variation, giving them a survival advantage
- disease less likely to affect pop (due to variation)
Disadvantages of SEXUAL reproduction
- takes time and energy to find mates
- difficult for isolated members of the species to reproduce
Advantages and disadvantages of SEXUAL reproduction in CROPS
(+) speed up natural selection through selective breeding - increasing yield
(-) takes a long time to grow new crops. Is dependent on sucessful pollination.
sepal
protects the unopened flower
petal
may be brightly coloured to attract insects
anther
produces and releases the male gamete (pollen grain)