Flashcards in Sexual Reproduction + Meiosis Deck (25)
What does meiosis result in?
How is ploidy restored in haploid gametes?
What makes up a homologous chromosome?
one maternal chromosome and one paternal chromosome
What makes a cell diploid?
it has two copies of the same information
one from mom and one from dad
What are the two steps of sexual reproduction?
animals can produce eggs that develop into offspring without fertilization
ex: insects, reptiles, and fish
What is the choice between asexual and sexual reproduction determined by?
Enviornmental factors that cause natural selection
type of asexual reproduction
each fragment grows into a full individual
ex: fungi, sea stars, worms
individuals contain a trait that can produce viable offspring
this leads to the offspring already being pregnant as well because they contain the trait
Who did a lot of work regarding sexual reproduction?
John Maynard Smith
What does asexual reproduction facilitate?
can produce more offspring than with sexual reproduction
Why do asexual species tend to die out?
there is not as much genetic variation to survive catosphroic events
asexual species often do not give rise to new species because there is not enough diversity (end lineage)
Disadvantages of sex
very costly to males (dangerous and uses resources)
How does sexual reproduction lead to greater genetic variation?
random combinations of egg and sperm
Physiological strategies for sexual reproduction
the number and types of chromosomes present in an organism
How many chromosomes are in a human cell?
we have 23 unique chromosomes and our cells are diploid, so we have 2 copies of each
How many autosomes do humans have?
how many copies
ex: humans ploidy number = 2
Where does the meiosis reduction division occur?
homologous chromosomes go from random distribution to distinct pairing
crossing over occurs
homologous chromosomes independently assort to the middle of the cell in 2 columns
chromosomes can line up in different orders