Ch. 42 Animal Reproduction and Development

Question 1

the life cycle of animals is dominated by the ___ stage

Answer 1

diploid

Question 2

haploid gametes are made by ___ in animals but made by ___ in plants and fungi

Answer 2

meiosis (animals)

mitosis (plants/fungi)

Question 3

clones

Answer 3

genetically identical cells or individuals (result of asexual reproduction)

Question 4

binary fission

Answer 4

type of asexual reproduction, genome replicates and cell divides (done by bacteria and archaea)

Question 5

budding

Answer 5

type of asexual reproduction, new organism develops from an outgrowth or bud due to cell division at a particular site and separates when mature
-done by yeast

Question 6

fragmentation

Answer 6

type of asexual reproduction, organism is split into fragments and each fragment becomes a mature organism
-done by molds, algae, sea stars, corals, worms

Question 7

parthenogenesis

Answer 7

type of asexual reproduction, occurs when a female gamete develops a new individual without being fertilized by a male gamete
-done by many invertebrates and some special vertebrates

Question 8

spermatozoa (sperm)

Answer 8

male gametes

Question 9

ova (eggs)

Answer 9

female gametes

Question 10

what results from the fusion of two gametes?

Answer 10

zygote

Question 11

what happens to the zygote?

Answer 11

divides by mitosis and becomes an embryo

Question 12

many asexually reproducing organisms can also reproduce sexually… true or false?

Answer 12

true!
environmental conditions are variable and being able to adapt to different conditions allows for greater reproductive success

Question 13

what are some advantages to being asexual?

Answer 13

• no competition for mates

- no spending energy to attract a mate

Question 14

what are some challenges to being asexual?

Answer 14

-everyone produces offspring, more competition and less survival of offspring

Question 15

costs of external fertilization

Answer 15

• higher failure rate for fertilization
• need large amounts of gametes
• need to get the egg/sperm as close as possible

Question 16

r-strategists

Answer 16

higher # of offspring, low energy investment, lower survival rates (fish)

Question 17

k-strategists

Answer 17

lower # of offspring, high energy investment, higher survival rates (humans)

Question 18

define oviparity

Answer 18

-producing young that hatch from eggs

Question 19

yolk

Answer 19

provides all the nutrients that the developing embryo needs until it hatches

Question 20

define viviparity

Answer 20

live birth

Question 21

amnion

Answer 21

a membrane surrounding a fluid-filled cavity that allows the embryo to develop in a watery environment
-key development = freedom from water for reproduction

Question 22

allantois

Answer 22

a second membrane that collects metabolic wastes

Question 23

chorion

Answer 23

third membrane that surrounds the entire embryo along with its yolk and the allantoic sac

Question 24

what are the extraembryonic membranes?

Answer 24

sheets of cells that extend out from the developing embryo

-includes the yolk sac, amnion, allantois, chorion

Question 25

placenta

Answer 25

• chorion and allantis fuse to form this in mammals who give live birth
• this organ allows nutrients to be obtained directly from the mother

Question 26

cleavage

Answer 26

early cell divisions of the zygote

Question 27

blastula

Answer 27

a hollow ball following cleavage (forms after morula)

Question 28

gastrula

Answer 28

multiple-layered embryonic stage of development

Question 29

what are the 2 phases of the menstrual cycle?

Answer 29

1. follicular phase

2. luteal phase

Question 30

what happens during the follicular phase?

Answer 30

• FSH stimulates maturation of an oocyte
• granulosa cells secrete secret estradiol (causes uterine wall to thicken)
• high levels of progesterone maintain thickened wall
• surge in LH follows this

Question 31

what does the surge in LH do?

Answer 31

causes ovulation (release of oocyte from the ovary)

Question 32

ovulation marks the beginning of the ____ phase

Answer 32

luteal

Question 33

what is the corpus luteum?

Answer 33

“yellow body”
formation of empty follicle cells post ovulation
secretes progesterone to maintain uterine lining
(if an embryo forms, the placenta takes over for progesterone production)

Question 34

what happens to the oocyte after ovulation?

Answer 34

is it taken to the fallopian tube and travels to the uterus

• if fertilized, forms embryo
• if not fertilized, corpus luteum degenerates, progesterone and estrogen levels drop, uterine lining is shed (menstruation)

Question 35

what is an estrus cycle?

Answer 35

uterine lining is reabsorbed instead of shed

-marked by the phases in which females are sexually receptive

Question 36

gametogenesis

Answer 36

the formation of gametes

Question 37

spermatogenesis (describe the process)

Answer 37

formation of sperm (occurs in the seminiferous tubules of the testes)
1. spermatogonia (2N) –> primary spermatocyte (N) –> secondary spermatocyte (N)

Question 38

oogenesis

Answer 38

formation of of ova or eggs

primary oocytes –> secondary oocytes –> polar bodies and 1 mature egg

Question 39

morula

Answer 39

solid ball of cells resulting form cleavage