Sexual Reproduction + Meiosis Flashcards Preview

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Flashcards in Sexual Reproduction + Meiosis Deck (25):
1

What does meiosis result in?

haploid gametes

2

How is ploidy restored in haploid gametes?

through fertilization

3

What makes up a homologous chromosome?

one maternal chromosome and one paternal chromosome

4

What makes a cell diploid?

it has two copies of the same information

one from mom and one from dad

5

What are the two steps of sexual reproduction?

Meiosis

Fertilization

6

Parthenogenesis

animals can produce eggs that develop into offspring without fertilization

ex: insects, reptiles, and fish

7

What is the choice between asexual and sexual reproduction determined by?

Enviornmental factors that cause natural selection

8

Fragmentation

type of asexual reproduction

each fragment grows into a full individual

ex: fungi, sea stars, worms

9

Cloning

individuals contain a trait that can produce viable offspring

this leads to the offspring already being pregnant as well because they contain the trait

10

Who did a lot of work regarding sexual reproduction?

John Maynard Smith

11

What does asexual reproduction facilitate?

exponential growth

can produce more offspring than with sexual reproduction

12

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)

13

Disadvantages of sex

very costly to males (dangerous and uses resources)

14

How does sexual reproduction lead to greater genetic variation?

independent assortment

crossing over

random combinations of egg and sperm

15

Physiological strategies for sexual reproduction

external fertilization

internal fertilization

16

karyotype

the number and types of chromosomes present in an organism

17

How many chromosomes are in a human cell?

46

we have 23 unique chromosomes and our cells are diploid, so we have 2 copies of each

18

How many autosomes do humans have?

22

19

autosome

non-sex chromosome

20

ploidy number

how many copies

ex: humans ploidy number = 2

21

Where does the meiosis reduction division occur?

Meiosis I

22

Prophase I

homologous chromosomes go from random distribution to distinct pairing

crossing over occurs

23

Metaphase I

homologous chromosomes independently assort to the middle of the cell in 2 columns

24

Independent assortment

chromosomes can line up in different orders

25

Crossing over

homologous chromosomes are linked together in synapsis (bivalent formation)

when they start to partially separate a chiasmata forms

this is where crossing over takes place