HSC Biology Module 5

asexual reproduction

production of identical offspring from just one parent through mitosis

why is binary fission not the same process as mitosis

there is no nucleus in a prokaryotic cell

where do all protists live

in aquatic or moist environments

what is the main mode of reproduction of protists

binary fission

why is the binary fission of protists different to that of bacteria

protists have a membrane bound nucleus that needs to be replicated

how is budding different to fission

the new organism is initially much smaller than the parent due to unequal division of cytoplasm

some fungi produce a cluster of spores in a

sporangium

rhizome

underground stem that branches into new roots and shoots

example of a rhizome

ginger

tuber

underground stems/roots that bud into new plants

example of a tuber

potatoes

cutting/fragmentation

pieces of broken branches or stems can develop into new identical plants

example of vegetation that reproduces by cutting/fragmentation

weeping willow

stolon/runner

above ground stem that creates new plants

example of a vegetation that reproduces by stolon/runner

strawberries

sucker

new shoots arise from parent’s roots

example of a vegetation that is a sucker

banana

bulb and corm

lateral buds that develop into new plants

example of a bulb and corm vegetation

daffodil

what is the main feature of sexual reproduction

alternation of generations

alternation of generations

alternate between haploid and diploid stages

how is alternation of generations shown in plants (stage /phase names)

sporophyte and gametophyte

mycelium

branching, threadlike hyphae often growing undergroun or sometimes over a surface

what three steps are there in the sexual formation of spores by fungi

plasmogamy (cytoplasm union), karyogamy (nuclear union) and gametangia (meiospores forming)

what two groups of plants are the only without vascular systems

mosses and liverworts

how is the gametophyte stage present in angio and gymnosperms

as a flower or cone

gymnosperms

non flowering plants

angiosperms

flowering plants

how are gymnosperms pollinated

by wind

how many sperm does a gymnosperm pollen grain divide into and how many fertilises the egg

divides into 2 but only one fertilises the egg

endosperm

tissue produced in seeds of most flowering plants following fertilisation that surrounds the embryo and provides nutrition in form of starch.

how do flowering plants ensure that they cross pollinate

their anthers and stigma mature at different rates

how are plants able to reject pollen from other species if inappropriate

pollen from each species has a characteristic shape that plants can recognise

what happens during external sexual fertilisation

the female lays unfertilised eggs into the water and the male deposits sperm onto egg (spawning)

what do corals form when an egg is fertilised by a sperm

a planula

what are some ADVANTAGES of external fertilisation

rapid and prolific, female can continue to reproduce as the first batch of young develop, parents spend less energy caring for young and gestation, young are widely dispersed young so less competition

DISADVANTAGES of external fertilisation

more gametes need to be produced, no control over gametes once released, decreased chance of successful fertilisation, must take place in an aquatic environment, increased risk of predation and disease

advantages of internal fertilisation

can take place on dry land, less gametes have to be produced, more likely to be successful, protected from predation and disease, developing young are fed

disadvantages of internal fertilisation

slower and fewer progeny, mating rituals are more complex, potential of STDs, energetically costly

how are the differences between monotromes, placental and mursupial mammals differentiated

length of growth time for fetus and how it is nourished during the growth period

uterus provides nourishment and protection via

placenta and umbilical cord

viviparous

they give birth to developed, live young

oviparous

lay eggs in which their young develop

what organ in the male reproductive system produce and store mature sperm

testes in scrotum

where are sperm cells formed

seminiferous tubules

where does LH hormone in the male reproductive system come from and what does LH stand for

luteinising hormone comes from the pituitary gland

what is LH for

production of testosterone in testes

oocytes

immature egg cells

what do the fallopian tubes have to catch the egg when released

fimbriae

zona pellucida

protective layer surrounding the egg that the sperm must penetrate to fertilise it

is it morula first or blastocyst first

morula —> blastocyst

morula

ball of UNSPECIALISED EMBRYONIC STEM CELLS

gastrula

stage in embryonic development when the blastula reorganises itself into three different layers