lesson 10 - sex Flashcards
what are the different types of asexual reproduction?
binary fission, budding, fragmentation, parthenogenesis
how do microtubules function in mitosis?
they form the spindle, which pulls chromosomes apart
what happens to the nucleus during eukaryotic mitosis?
the nuclear envelope breaks down
what is isogamy?
fusion of similar gametes that are morphologically similar
fragmentation
broken pieces of an organism grow into new individuals
(if a starfish loses an arm, that arm can sometimes grow into a whole new starfish)
budding
small organism grows from the parent through budding. once fully developed, the new Hydra breaks off and starts living independently
how do bacteria divide?
binary fission, where origins of replication move to opposite poles
binary fission
parent cell duplicates its DNA and splits into two identical daughter cells
parthenogenesis
having babies without needing males because females can lay eggs on her own
what is the haplodiplontic life cycle?
organism alternates between haploid and diploid multicellular stages
what are the three main life history patterns in sexual reproduction?
diplontic, haplontic, and haplodiontic
why doesn’t asexual reproduction enhance genetic variation?
because it produces clonal offspring without recombination
what is a diplontic life cycle?
diploid phases dominates
what is a haplontic life cycle?
haploid phase dominates
why are haplontic life cycle beneficial?
fewer chromosomes = fewer mutations
what stage is sporophyte?
diploid stage
what stage is gametophyte?
haploid
what does sporophytes produce?
spores
what do gametophyte produce?
gametes
why are diplontic life cycles beneficial?
two copies of chromosomes = more mutations
what is sexual dimorphism?
differences in physical traits between males and females due to sexual selection
what are the two types of sexual selection?
intersexual selection and intersexual selection
intrasexual selection
competition between members of the same sex for mates
intersexual selection
mate choice, where one sex selects mates based on a preferred trait
what is an example of male competition for mates?
agonistic behaviour, where males compete in contests to gain access to females
how do females drive sexual selection?
by choosing mates with desirable traits
what are the main types of sexual reproduction strategies?
dioecious, monoecious, hermaphroditic
dioecious
separate male and female organisms
monoecious
one organism produces both gametes
hermaphroditic
can self-fertilize
what are the three main mating systems?
monogamy, polygamy, and polyandry
monogamy
one male and one female
polygyny
one male mates with many females
polyandry
one female mates with many males
what are the three main types of sexual reproduction?
isogamy, anisogamy, and oogamy
fusion of similar gametes, high quantity, low investment
isogamy
parents makes two different types of cells
anisogamy and oogamy
what is the function of meiosis?
reduces chromosomes number, so babies don’t have too many chromosomes
what is the function of fertilization?
restores diploid chromosome number
true or false - eukaryotes have circular chromosomes
false - eukaryotes have linear chromosomes
why is a haplontic cycle beneficial in stable environments?
fewer chromosomes means fewer mutations (if the environment is already stable, they do not need much changes)
why is a diplontic cycle beneficial in changing environments?
two copies of each gene allow masking of harmful mutations
how does haplodiplontic cycle help organisms adapt?
different stages can thrive in different environments, reducing competition
why are complex species typically diploid?
more cells mean more chances for mutations, which diploidy can mask
what happens to somatic mutations in diploids?
they are not passed to offspring and are often masked by a second copy
