Plant reproduction Flashcards
What is parthenogenesis?
a natural form of asexual reproduction in which growth and development of embryos occur without fertilization
Describe what asexual reproduction is
one parent produces genetically identical offspring
Whats the difference between asexual and sexual reproduction?
Asexual; 1 parent, sexual; 2 parents
asexual; genetically identical offspring, sexual; genetic variation among offspring
What are the costs of sex?
- meiosis, recombination can expose harmful alleic combinations
- meiosis is slow
- energy used through mating
What are the benefits of sex?
- sheds harmful mutations
- brings beneficial mutations into same genetic background
- more rapid evolution
Which form of reproduction is faster?
Asexual
What’s the difference between life cycles in plants and life cycles in animals?
Animal life cycle = diplontic
Land plant life cycle = haplodiplontic
What’s teh difference between a haploid and a diploid cell?
Haploid = single set of unpaired chromosomes Diploid = 2 complete sets of chromosomes, one from each parent
Whats the difference between a diplontic and a haplontic life cycle?
diplontic; main form is diploid
consists of free living in sporophyte in plants
haplontic; main form is haploid
consists of free living gametophyte
Where does genetic variation come form in the land life cycle?
meiosis, where plant spores are made
What is a sporophyte?
the asexual and usually diploid phase in plant life cycle
producing spores from which the gametophyte arises
What is dominant form in vascular plants?
sporophyte
What was the dominant form in early evolving plants?
gametophyte
Describe the stages in a haplodiplontic life cycle of a plant?
- gametophyte produces male and female gametes by mitosis
- fusion of gametes produces a diploid zygote
- this zygote develops into a sporophyte
- sporophyte undergoes meiosis to makes spores
- spores undergo mitosis to form gametophyte
What is a gametophyte?(in the life cycle of plants with alternating generations)
the gamete-producing and usually haploid phase, producing the zygote from which the sporophyte arises.
What is the dominant form in bryophytes?
gametophyte
What were the first plants on land?
bryophytes
What was teh problem when plants moved from water to land?
they have motile sperm which swim so now there was no medium to disperse sex cells
What is the significance of sphagnum moss?
first vascular plants to be spore bearing
How are plant gametes produced?
by mitosis
How are spores produced?
by meiosis
What is an angiosperm?
a flowering/fruit bearing plant that have ovules develop in an enclosed ovary
Name some strategies for dispersal of pollen
- wind dispersal
- animal dispersal
Difference between a monocot and a dicot?
monocot contains one leaf, dicot contains 2 true leaves
Difference between seeds and spores?
spores= haploid, unicellular, formed by meiosis seeds = diploid, multicellular, formed by mitosis
Benefits of cross pollination and self pollination?
cross= beneficial due to genetic variation self = can be quicker
Difference between monoecious and dioecious plants?
monoecious = male and female reproductive organs on same plant dioecious = separate male and female organs on different plants
What are some mechanisms to prevent self pollination?
- genetic mechanisms to ensure outcrossing
- or to ensure cross pollination
- dioecious plants, cant self pollinate
How does inter specific incompatibility prevent self pollination?
- pollen is rejected from donors of species different to that of the recipient because it is too dissimilar
How does intra specific incompatibility prevent self pollination?
- pollen that originates from a donor plant of teh same species is rejected because it is too similar
What is self incompatibility of a plant?
- the inability of a fully fertile hermaphroditic plant to produce zygotes when self pollinated
What is teh difference between gametophic SI and sporophytic SI?
g SI = controlled by pollen haploid genotype
s SI= controlled by diploid pollen parental genotype
describe 3 things about spores
haploid
unicellular
produced by meiosis
In a plants reproductive cycle, do they have multicellular or unicellular stages?
multicellular
what are the 4 stages in the order of plant evolution?
water to land
first vascular plants
first seed plants
flowering plants
Describe the 2 multicellular stages in a plant
1) gametophyte to gametes to zygote
2) sporophyte to spores to gametophyte
difference between spores and seeds
spores; haploid, multicellular, formed by meiosis
seeds; diploid, unicellular, formed by mitosis
