Please enable JavaScript.
Coggle requires JavaScript to display documents.
Mechanisms of Reproduction ensuring Continuity of Species - Coggle Diagram
Mechanisms of Reproduction ensuring Continuity of Species
sexual reproduction
animals
internal fertilisation
inside body
terrestrial organisms
external fertilisation
outside body
aquatic organisms
fertilisation
haploid nucleus of egg and sperm fuse
forms fertilised egg/zygote
egg/zygote needs to be hydrated
plants
reproductive organ structure
male
anther
makes up top part of stamen
female
carpel
top part=stigma
pollen grains must land
stigma supported by style
base=ovary
disadvantage
fusion of gametes harder than animals
grow in ground
unable to move
self-fertilisation
advantage
less energy
no structures to attract pollinators
grows in areas with little animals
one plant
cross-pollination
requires external agents for fertilisation
wind, water, animals
advantage
greater variation
mix of genetics
seed dispersion
spread over wide distance
less competition
germination
when seed land in suitable soil
fungi
Plasmogamy
fusion of 2 protoplast
contents of 2 cells
brings together 2 compatible haploid nuclei
Karyogamy
fusion of haploid cells
formation of zygote (diploid)
meisois
cell division
reduce chromosome number to haploid
Asexual reproduction (AR)
binary fission
protists
amoeba
bacteria
E. Coli
splitting into 2
main method AR in unicellular
process
newly divided cell grows x2 size
replicates DNA
splits into 2 identical cells
advantage
rapid population growth
over short period of time
adverse conditions
requires only one parent
disadvantage
no genetic diversity
budding
Fungi
yeast
protists
protozoa
adult organisms grows small bud
separates from parent
create new individual
advantage
rapid population growth
if environment does not change
identical offspring will survive
disadvantage
if environment changes
entire species will die out
spores
fungi
mushrooms
mushroom cap above hyphae
mushroom cap has basidia
produce spores
tiny, unicellular reproductive cells
advantage
spores expand distrubution
enable species to colonise new environments
only require one cell
process
hyphae
network structure of fine threads
from mycelium
have ends capable of producing spores
Sporangia
only produced in favourable conditions
plants
through vegetative propagation
plant grow from vegetative organs
stems, roots, leaves
runners
long, thin, modified stems
grow along surface of soil
cultivated strawberries
leaves, flowers, roots
produced at every alternate node
on stem
beyond each second node
node turns up & thickens
produce new roots & shoots
rhizomes
underground horizontal modified stems
rise new shoots at every node
Gardeners
split rhizomes
propgate ferns
suckers
modified roots
in trees or shrubs
spread quickly
into vacant patch habitat
after disturbance
allows for rapid regrowth
Colony Wattle (Acacia Murrayana)
sends up shoots
from outer roots
grow into separate plants
when parent shrub dies
apomixis
some plants produce offspring
from special generative tissue
without fertilisation of seeds
kangaroo grass, lemons, orange, dandelions
advantages
multiplication is rapid
plantlets produce seeds
increases seed dispersal
disadvantage
lack variation
animals - parthenogenesis
unfertilised egg develops into functional offspring
bees
queen bee produces egg (meiosis)
undergoes parthenogenesis
to produce haploid drone bee
Reproduction
ability of organisms
to produce offspring
ensures continuity of species
sexual reproduction
involves 2 parents
meeting of gametes
Gametes=sex cells (egg and sperm)
produce offspring with
mix of parents genes
advantages
genetic variation
random variation present
species survive environmental changes
disadvantages
greater expenditure
time and energy
requires mating partner
fewer offspring produced
asexual reproduction
involves only 1 parent
gives rise to offsrping genetically identical
each other & parent
advantages
rapid population growth
no mates is required
less energy required
competitive advantage
in well adapted environments
disadvantages
lack of variation
lead to large-scale extinction
if environment changes