heredity - reproduction Flashcards
How does reproduction ensure the continuity of a species?
without reproduction, new individuals are not produced → species will go extinct
in stable environments, asexual reproduction is advantageous → large numbers of offspring + minimal energy used
sexual reproduction → variation → increases the likelihood of a species surviving environmental changes (favourable traits)
agricultural practices → potential to negatively influence the genetic of a species
advantages of external fertilisation
little energy required
large number of offspring
offspring spread more widely → less competition
disadvantages of external fertilisation
gametes go unfertilised
offspring less protected
offspring die from environment
advantages of internal fertilisation
more likely to occur
embryo protected from predators
more likely to survive
disadvantages of internal fertilisation
high energy
less offspring
more energy to raise offspring
plant fertilisation
The process of the male gamete (pollen) uniting with the female gamete (ovum)
pollination
Transfer of gametes from one plant to another
pollinating agents
wind or animals (bees) - agents that help pollen spread from one plant to another
self pollination
Pollination of the one flower by its own pollen. These are less genetically diverse.
cross pollination
rely on outside agents for transfer of pollen from one plant to another.
asexual advantages and disadvantages
efficient/fast
short time required to reproduce
no variation → increase risk of disease
hyphae
tiny thread of cytoplasm surrounded by a plasma membrane → covered by a wall of chitin
mycelium
feeding structure of a fungus → below ground
HOMOthallic
self-fertile → ability of a single spore to produce sexually reproducing colony
HETEROthallic
Requires haploid cells to fuse in order to produce new individuals.
binary fission
cell elongates → genome replicates (any plasmids replicate) → DNA separates to either side → cleavage furrow → two identical daughter cells