Why is sex interesting? Flashcards
What are the characteristics of sex?
Different organisms producing different, specialised cells by meiosis
These cells are haploid gametes
What is isogamy
Gametes identical in size
What is anisogamy
Asymmetrical gametes
What is budding?
smaller version of the organism grows on you then pops off
how do bacteria, protists and some unicellular fungi reproduce
asexually - binary fission
how do baker’s yeast, hydra and anemones reproduce
asexually - budding
how do plants reproduce
asexually - vegetative reproduction
Give examples of vegetative reproduction
bulb splits
potato bits break off and form new potato plants
air plants reproduce in a similar way to budding
how do some fungi and algae reproduce
asexually - spores
why are spores not gametes
diploid cells - have the same number of chromosomes as parents
how do lichens, annelids, sea stars and plants reproduce
asexually - fragmentation
what is fragmentation reproduction
parts of an individuals break off and then grow into a new individual
Give examples of fragmentation reproduction
star fish arms can grow new bodies
Japanese knotweed grows into lots of new plants if cut up
How do rotifers, insects, reptiles and amphibians reproduce
asexually -parthenogenesis
what is parthenogenesis reproduction
females lay eggs or give birth without fertilisation
What five things make sexual reproduction costly
requires two sexes conflict need to produce gametes risk of catching STIs Own genes diluted by 50% with those of partner
why does the need for two sexes make sexual reproduction costly
Spend lots of time and energy looking for a mate or gamete of the same species (eg lots of gametes in the ocean so hard to find the gamete of the same species)
Need to persuade a mate - courtship (eg courtship dances and rituals use lots of energy and exposes the males to predators)
Why does conflict make sexual reproduction costly
waste energy fighting other males
risk of death, injury and not securing a partner
why does the need for gametes make sexual reproduction costly
most gametes are wasted
(eg lots of sperm released but only one fertilises an egg/lots of eggs released into the sea but only a couple develop into fish)
describe the twofold cost of sex
sexual females have half the amount of daughters of asexual females so population grows at half the rate
how long has sex been around for
1.2 billion years
are the most life forms sexual or asexual
sexual
are the most organisms sexual or asexual
asexual
which lineage outcompetes the other in regard to reproduction
sexual reproduction outcompetes asexual reproduction
