Mod 5 Flashcards
asexual reproduction in plants
what is the role of spores in the asexual reproduction of fungi?
for the dispersal and reproduction of genetically identical fungi. spores form by meiotic cell divisions
sexual reproduction in plants
what is the role of spores in the sexual reproduction of fungi?
asexual reproduction in plants
How is budding different from the production of spores
budding is the production of a new individual directly from an outgrowth of the parent cell. Spore production occurs by multiple cell divisions within specific structures
sexual reproduction in plants
explain how reproduction in fungi maintains the continuity of the species
IMPORTANT
fungal hyphae are generally haploid. Azexual reproduction maintains this by production genetically identical haploid spores. Sexual reproduction produces a diploid cell with paired chromosomes that undergo meiosis to continue the process of producing haploid cells (spores), which in turn germinate to produce haploid fungi
sexual reproduction in plants
compare and contrast asexual and sexual reproductive processess in plants
you can use rhizopus and yeast as an example
in both rhizopus and yeast, haploid gametes form a diploid cell, then undergo meiosis to form haploid spores. However, in Rhizopus this is achieved by specific gamete cells on amture hyphae. In yeast the whole organism/cell fuses with a matching mating type to form the diploid cell before undergoing meiosis.
asexuala reproduction in cellular slime moulds
compare and contrast binary fission and multiple fission
binary fission produces two new free living cells from a single division of the nucleus. Multiple fission produces multiple nucleii before the division of the cytoplasm to create multiple new cells.
asexual reproduction in plants
What is the purpose of colony formation in protists
can use cellular slime moulds as example
colony formations allow the species to disperse into new areas and produce offspring that can further assist in dispersion
asexual reproduction in animals
what is the advantage of fragmentation to an animal with a relatively simple body plan and why wouldn’t this work for more complex animals?
can use the example of a flatworm
fragmentation allows the flatworm to rapidly reproduce and colonise a favourable environment. Injured flatworms are able to regenerate their lost body and are therefore hardy organisms.
asexual reproduction in animals
all individuals produced by budding or fragmentation are clones. Explain why this might leave a population vulnerable if environmental conditions rapidly changed
a population consisting of genetic duplicates are less likely to survive changing environmental conditions because of their lack of diversity.
asexual reproduction in plants
define vegetative propagation and its purpose
vegetative propagation is any asexual reproduction of plants in which a new plant grows from a fragment of vegetative tissue from the parent plant
asexual reproduction in plants
what feature of plant cells favour vegetative propagation
plant cells at the growing tips of the plant are totipotent (essentially stem cells) so can differentiate to form all the tissues of the adult plants
asexual reproduction in plants
describe some of the natural means of vegetative propagation in plants
can find explanation in dictionary
rhizomes
stem and root tubers
runners
corms
bulbs
plantlets
asexual reproduction in plants
how are plants favoured/not favoured by vegetative reproduction
vegetative reproduction enables a well adapted plant to spread rapidly and saturate its environment. They have a competitive advantage to plants that invest their energy into producing and germinating seeds, as this method allows the plant to invest its resources into growth.
However, vegetative propagation between the plants would be unfavourable when faced with selection pressures such as changing environments due to a lack of genetic variation
asexual reproduction in plants
what are the advantages for humans of vegetative propagation
high yeild of the most genetically successful characteristics in plants, use less resources and time for growing and seeding
reproduction in ferns (plant reproduction)
what feature distinguishes ferns from seed plants
seed plants are angiosperms and gymnosperms
seed plants produce seeds from which a new plant grows, whereas ferns release spores that produce a prothallus, which in turn grows a fern
reproduction in ferns (plant reproduction)
Why do ferms require moist environments in order to reproduce? why does this requirement limit their survival in the long term?
fern gametophytes produce motile sprem cells which must swim using a film of water to the egg cell for fertilisation.
Ferns are limited to area where water is relatively abundant as the prothallus is susceptible to dring out, and the sperm need water to reach the egg. They are therefore not well adapted to drier environments
sexual reproduction in angiosperms (plant reproduction)
in which part of a flowering plant do the male/female gametophytes develop
anther/ovule
sexual reproduction in angiosperms (plant reproduction)
why don’t angiosperms need a moist environment for fertilisation to occur
the gametes are carried by pollen directly from the male to the female parts of the flower. The pollen is either transported by wind or other organisms.
sexual reproduction in gymnosperms (plant reproduction)
how does the sperm cell reach/fertilise the egg in conifers
pollen sticks to a drop of fluid in the micropyle. The fluid evaporates brigning the pollen close to the egg cell. A pollen tube develops and the sperm cell moves through it to the egg cell.
sexual reproduction in gymnosperms (plant reproduction)
which structure in a conifer is equivalent to the embryo sac of angiosperms
idfk
sexual reproduction in gymnosperms (plant reproduction)
what is the role of wind in the complete life cycle of a conifer
wind transports the male gamete (pollen) to the female gamete (egg cell) for fertilisation
asexual reproduction of plant cells
how is budding different from binary fission
With budding, a parent cell creates an outgrowth that eventually becomes a daughter cell. With binary fission, a parent cell reproduces by splitting in half. Both binary fission and budding are asexual, leading to genetically identical cells.
animal sexual reproduction
describe one advantage/disadvantage of sexual reproduction
adv - offspring have more genetic diversity, meaning populations of sexual organisms are more likely to survive selective pressures
dis - requires more energy and time to mate/reproduce, more likely to lead to the extinction of a species as they need a mate. fertilisation and embryonic growth are slower than asexual reproduction
animal sexual reproduction
distinguish between internal fertilisation and external fertilisation, identifying advantages of each strategies
external fertilisation fertilises eggs outside of the parent. The chance of the fertilisiation is low, but increased by the synchronised release of very large numbers of eggs and sperm (spawning). This also proves a lower risk to the parent organisms.
in internal fertilisation, the eggs are fertilised inside the body of the female by sperm deposited by the male. This increases the chance of fertilisation but carries a higher risk of mortality for the parent organisms.
animal sexual reproduction
describle two features of the amniote egg that makes it an ideal adaptation to reproduction on land
eg bird
provides protection from physical damages/dehydration in terrestrial environment
provides nutrients and stores wastes for the period of the embryonic development
animal sexual reproduction
using examples, distinguish between oviparous and viviparous vertebrates
in oviparous vertebrates, the embryo develeops in the egg after it is laid
in viviparous vertebrates, teh young develop inside the mother, deriving nutrients from the parent.
animal sexual reproduction
some frogs and toads have evolved novel ways of enhancing the survival of their eggs. provide an example of this
midwife toad or surinam toad
male midwife toad carries eggs, keeps them moist and places them in a favourable habitat to hatch
In the Surinam toad, spongy skin on the female’s back encloses and protects teh eggs until they hatch
animal sexual reproduction
name two vertebrates that produce shelled, waterproof eggs
birds/reptiles
animal sexual reproduction
what feature of a vertebrate egg has been primarily responsible for its success
watertight/protective shells that prevent dessication and enables reproduction to be independent of water
animal sexual reproduction
explain how a vertebrate egg eliminates wastes for a developing embryo
wastes collect in the allantois where they are stored throughout embryonic development
animal sexual reproduction
explain how a vertebrate egg allows gas exchange to a developing embryo
the shell is permeable to gases. Blood vessels in the inner membrane perform gas exchange.
animal sexual reproduction
explain how a vertebrate egg provides nutrition to a developing embryo
the yolk is mainly fat and the albumin is mainly protein
animal sexual reproduction
describe different ways in which animals can allocate their total reproductive effort
animals can allocate theri reproductive effort to prioritise either the number of young they produce or how well they care for them. If they produce a large number of young, they will not have enough energy for parental care. Many will die but enough will survive. If only a few offspring are produced there is enough energy to care for them and most will survive.
