Sexual and Asexual Reproduction Flashcards
Characteristics of asexual reproduction
single parent cell
can replicate without another organism’s genetic material
genetically identical offspring
characteristics of sexual reproduction
two different individuals combine their genetics to produce a new individual
genetic information is carried in the chromosome of a gamete
gamete are haploid cells
together two gametes combine to create a diploid zygote –> embryo
pros and cons of asexual reproduction
only 1 parent
time and energy efficient
rapid population growth
offspring genetically identical to parent (both good and bad)
pros and cons of sexual reproduction
2 parent organisms
time and energy inefficient
slower population growth
offspring genetically variable
adaptation and selection lead to evolution
more resistant to disease and can survive better
types of asexual reproduction
- binary/mutiple fission
- fragmentation
- budding
- vegetative propogation
- parthenogenesis
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what organisms undergo sexual reproduction?
only eukaryotic organisms
- dioecious (make or female reproductive systems)
- monoecious (can have both either at the same time (hermaphrodites), or have one then change to another)
the two locations where embryos can develop?
oviparous
- embryo develops internally in an egg
viviparous
- embryo develops internally in an organism
Fission
parent cell/organism seperates itself into equally sized daughter cells or organisms
all kingdoms and domains do this
most common in bacteria, archaea and protista
Binary fission
two equally sized offspring produced
common in prokaryotes
initial enlargement of the parent cell and the duplication of the parent nucleus before division
Multiple fission
fission resulting in multiple offspring
more common in protista
very fast
division of the nucleus into many parts adn the cytoplasm forms aroudn the nuclei and the cells seperate
often have multi-nuclide (many nucleuses) within their cells
Budding
found in all domains and kingdoms
boht uni and multicellular organisms
outgrowth on the parent cell/organism that breaks off
usually occurs in specific places, but can theoretically occur anywhere
it breaks off to form a new smaller daughter cell that are different sizes
Fragmentation
parent organisms breaks into fragments that can grow indeendently into a full organism
identical to the parent organism
intentional and unintentional
vegetative propogation
similar to fragmentation
a new full organism can form from a piece of its parent organism
only occurs with plants
since plants are sedentary, it often involved the fragment moving away from the parent plant
parthenogenesis
multicellular plant or animal
development of an organisms from an unfertilised gamete, most commonly an egg cell
often occurs in organisms that can undergo sexual reproduction
part of the mechanism that determines sex in some species
How can asexual reproduction occur in plants
production of seeds without fertilisation, called apomixis
planting of buds, for potatoes
artificial asexual reproductive methods of plants
graftung
cutting
layering
micropropogation
how does grafting work?
the upper portion of one plant is attached to the lower portion of another
forming a graft
the upper part is called the scion
the lower part is called the rootstock
Which organisms are mainly haploid and which are mainly diploid/differences?
fungi are usualyl primarily haploid, whereas other organisms are usualyl diploid in their lifetimes
Some alternate between both (also usually fungi)
an organism produces sports, which are haploid. These then develop into a haploid organism. They then produce gametes, which combine to produce a diploid zygote that develops into a diploid individual called a sporophyte
Monoecious
hermaphrodites/organisms can be both female and male either at the same time or one after the other
sexual reproduction is thought to have evolved from this
evertone can produce offspring
usually presents as having a female and male flower on the same plant
in animals, both parents produce offspring when they mate
some can also change their sexes throughout their lives
dioecious
male and female are different organisms
halves the number of individuals that can produce offspring
reduces the risk of self-fertilisation and increases genetic variability
occured via the gradual increase in one of the sex roles
what are isogamy and anisogamy/
isogamy: gametes are the same size
anisogamy: gametes are different size
often females produce larger gametes than males (and less) therefore resulting in selection pressures that eventually differentiated the created into two sexes
How are flowers used to reproduce?
produce and release sperm
create and store eggs
capture sperm for fertilisation
4 floral organs
sepals
petals
stamens
carpels
