reproduction Flashcards
(135 cards)
1
Q
what is asexual reproduction the creation of?
A
new individuals by the process of mitosis
2
Q
what does asexual reproduction create?
A
identical offspring rapidly
3
Q
asexual reproduction is common with?
A
many invertebrates
4
Q
3 types of asexual reproduction
A
fission
budding
fragmentation
5
Q
what is fission? examples?
A
division of parent into 2 genetically identical individuals
amoeba, bactera (bindary fission instead of mitosis)
6
Q
what is budding? examples?
A
new individuals pinch off from an existing one to form a colony
yeast, hydra, corals
7
Q
what is fragmentation? example?
A
breaking off of the body into smaller pieces that then develop into complete adults through regeneration
sea stars, planaria
8
Q
advantage of asexual reproduction
A
animals living in isolation can produce offspring without a mate
many offspring are created in a short amount of time
9
Q
what is sexual reproduction?
A
creation of oddspring when 2 haploid gametes come together to form a diploid zygote
10
Q
when are gametes made?
A
meiosis
11
Q
ffemale gamete
A
ovum/oocyte
12
Q
male gamete
A
sperm/spermatozoan `
13
Q
what does sexual reproduction increase?
A
genetic variation amongst offspring by inheriting genes from 2 parents
14
Q
what does the variability in sexual reproduction enhance?
A
Darwinian fitness and survival when environmental factors change
15
Q
who can reproduce both sexually and asexually?
A
freshwater crustacean Daphnia
16
Q
under favorable conditions, how do Daphnia reproduce?
A
parthenogenesis/virgin birth
17
Q
parthenogenesis
A
mother organisms form genetically identical daughters/clones that d nit need to be fertilized
18
Q
what is the advantage of parthenogenesis?
A
allows numbers to increase rapidly in short growing periods
19
Q
under unfavorable conditions, how do Daphnia reproduce?
A
give birth to males + sexual females so that mating can occur and some can survive
20
Q
where is parthenogenesis seen?
A
species with social organization like bees ad ants
some vertebrates lie fish, birds, amphibians, and lizards
21
Q
how is parthenogenesis in ants?
A
male drones develop by parthenogenesis, while female sterile workers and fertile queen develop from fertilized eggs
22
Q
most animals’ reproductive cycles are linked to?
A
changing seasons
23
Q
what does reproductive cycles being linked to season allow?
A
conservation of energy and reproduce hen condiions are favorable
24
Q
what does reproductive cycles being linked to season allow?
A
conservation of energy and reproduce when conditions are favorable
25
what are reproductive cycles also controlled by?
hormones and environmental cues like temp, rainfall, daylength, and lunar cycles
26
who is sexual reproduction difficult for?
sessile organisms (dont move) and burrowing animals who may never encounter a member of the opposite sex
27
how is the prob;em of sexual reproduction for sessile animals solved?
synchronous hermaphroditism
28
hermaphroditism
having both male and female reproductive systems
-many still must mate with another member of the same species(earthworms)
29
sequential hermaphroditism
when an individual changes its sex/gonads during its lifetime
30
male to female
protoandrous
31
female to male
protogynous
32
what is sex reversal associated with?
age and size
33
sequential hermaphroditism in clownfish
in some clownfish species, oldest and the biggest individual can change from male to female is there are not enough females around
34
fertilization
joining of egg and sperm
35
external fertilization
eggs and sperm meet in the environment
always occurs in water
environmental cues like, temp, day length and pheromones or nonenvironmental cues like courtship behavior, influence gametes release
produce large numbers of zygotes and few survive
36
internal fertilization
sperm are deposited in or near female's reproductive tracts
produce fewer zygotes with more parental care, hence greater survival
37
gonads
organs that produce gametes
ovaries - female
testicles - male
38
single opening for both excretion of waste and reproduction
cloaca
39
examples of organism with cloacas
non mammalian vertebrate - birds and fish
(most mammals have 2 separate openings)
40
spermatogenesis
production of mature sperm cells
41
how does structure of sperm fit function?
head region contains 1n nucleus that is tipped with enzymes called the acrosome that help the sperm penetrate the egg
behind the egg are many mitochondria that provide ATP for movement of the flagellum
42
what parts of the sperm enter the ovum?
head - DNA (nucleus) and centriole
43
oogenesis
develpoment of ova
44
ova
unfertilized egg cells
45
how many follicles do women have?
~400,000
46
when do women get all their follicles?
formed before birth, but they are not "ready"
47
follicle
1 egg surrounded by layers called follicle cells
48
what do follicle cells do?
protect and nourish developing egg
49
at birth, how are all the eggs in a woman?
diploid and in g1 interphase of meiosis
50
what happens to the eggs between birth and puberty?
all reach prophase i of meiosis and are essentially stuck there for a while
51
what happens during puberty?
a single primary oocyte completes meiosis each month
52
how does a primary oocyte complete meiosis?
FSH hormone stimulates one follicle "the chosen one" to go through meiosis I each month
53
what happens at the end of meiosis I?
the secondary oocyte is formed and is then released from the ovary with ovulation to go wait in the fallopian tubes/oviduct
54
how is the meiotic division in puberty?
unequal- the secondary oocyte gets almost all the cytosol and organelles and the 1st polar body is much smaller
55
how is meiosis II/second mitotic division induced?
when a sperm penetrates the secondary oocyte to produce the haploid ovum/egg
56
what happenes to the 2nd polar body?
it separates from the ovum, while the haploid ovum and sperm's nuclei fuse= fertilization
57
what does the secondary oocyte leave behind when it leaves the ovary during ovulation?
leaves behind follicular tissue
58
what does the follicular tissue develop into?
corpus luteum in the ovary
59
what does the corpus luteum do?
secretes hormones estrogen and progesterone that maintain the uterine lining during pregnancy
60
what happens to the corpus luteum when the secondary oocyte is not fertilized?
it degenerates and the woman has her period then a new follicle matures during the next cycle
61
principle hormones of males
steroid hormones called androgens
62
important androgen
testosterone
63
what does testosterone do?
primary sex characteristics that are associated with the reproductive system
secondary sex characteristics that are not directly related to the reproductive system
64
primary sex characteristics
sperm production and development of reproductive structures
65
secondary sex characteristics
deepening of the voice, hair growth, and more muscle growth
66
how many eggs do females release per cycle?
1 or a few eggs
67
2 different types of cycles
human and primates - menstrual cycles
estrous cycles - dogs
68
similarity between menstrual and estrous cycles
ovulation at the endometrium lining of the uterus thickens and develops a rich blood supply in preparation for an embryo
69
difference between menstrual cycle and estrous cycle
m - if ovum is not fertilized, the uterine lining is shed
e - endometrium is reabsorbed by the uterus
70
FSH
Follicle Stimulating Hormone
71
LH
Luteinizing Hormone
72
how is FSH involved?
involved in the development of the growing follicle
73
why isnt LH initially helping the growing follicle?
there are no receptors for it on the growing follicle
74
where are FSH and LH secreted from?
pituitary glands
75
what do FSH and LSH stimulate?
the release of estrogen and progesterone
76
does the follicle get receptors for LH?
yes, as it grows larger with the aid of FSH, it eventually develops receptor sites for LH
77
what type of feedback do LH and FSH have?
positive - it is actually LH that induces ovulation of secondary oocyte
78
after ovulation, what does LH do?
stimulates the remaining follicular tissue left behind when the secondary oocyte was released to form the corpus luteum
79
after the corpus luteum is formed, what doesLH do next?
triggers it to secrete estrogen and progesterone
80
what happens to the hormones when corpus luteum disintegrates?
estrogen and progesterone levels decrease and induces menstruation
81
what happens to estrogen and progesterone levels when a women is pregnant?
levels remain high
82
what is estrogen responsible for?
secondary sex characteristics like high water retention, breast development, and calcium metabolism
83
menopause
women cease to ovulate/menstruate
84
why do women go through menopause?
ovaries lose their responsiveness to the hormones FSH and LH which then causes the decline of estrogen and progesterone
85
why do older women tend to have osteoporosis?
estrogen linked to calcium metabolism, so low levels of that causes weak bones
"bone pores"
86
gestation
pregnancy
is the condition of carrying one or more embryos
87
conception
fertilization of an egg by a sperm
88
when does a zygote start cleavaging?
24 hours after fertilization
89
morula
division of zygote until a forms a solid ball of cells
90
blastula
morula continues to divide, becoming a hollow ball
91
gastrulation
cells invaginate to form a gastrula
92
what begins with the formation of a gastrula?
differentiation of body structures
93
placenta
disk-shaped organ
94
what does the placenta contain?
embryonic and maternal blood vessels
95
what does the placenta exchange? via what?
materials between the mother and embryo like nutrients, respiratory gases
arteries and veins of the embryo's umbilical cord
96
what does the placenta dispose?
metabolic waste from the embryo
97
organogenesis
development of organs
98
when does organogenesis occur?
first trimester
99
what is the embryo considered as after the first trimester?
fetus because of all the major structures of the adult are present in rudimentary form
100
during the 1st trimester, what does the embryo secrete?
hormone human chorionic gonotrophin (HCG)
101
what does HCG do?
maintains the secretion of progesterone and estrogen by the corpus luteum and keeps the endometrium lining intact
102
what does a pregnancy test detect in urine?
high levels of HCG
103
what happens during the 2nd trimester when HCG levels drops?
corpus luteum deteriorates and the placenta secretes its own estrogen and progesterone to maintain the lining
104
when are estrogen levels the highest?
near the end of the pregnancy in the thrid trimester
105
what does the high levels of estrogen trigger?
the release of oxytocin receptors on the uterus
local regulator prostaglandins are secreted
106
what does oxytocin cause?
causes powerful contractions of the smooth muscles of the uterus
107
what does prostaglandin do?
enhance contractions and cause pain
108
what happens to mammals after birth?
lactation
109
what stimulates milk production in the mammary glands?
the pituitary glands produce prolactin that is controlled by the hormone oxytocin
110
what are birth control a combination of?
synthetic estrogen and progesterone
111
what feedback are birth control pills?
negative feedback by stopping the release of FSH and LH thus preventing ovulation
112
what three stages of cell division follow fertilization?
cleavage
gastrulation
organogenesis
113
cleavage
zygote divides to from the solid morula then hollow/fluid-filled blastula
114
gastrulation
3 germ layers form
115
organogenesis
generates rudimentary organs from which adult structures will grow
116
what does the cell cycle during cleavage consist of?
s-phase of interphase where DNA gets copied
m-phase where mitosis occurs, cytokinesis
117
what does the embryo do during cleavage?
partitions the cytoplasm of the zygote into many smaller calls called blastomeres and does not enlarge
118
deuterostomes
second mouth
echinoderms (sea stars) and chordates (humans)
119
cleavage in deuterostomes
radial - upper four cleavage are aligned directly over the lower four blastomeres
120
protosomes
first mouth
mollusks (shells)
annelids (segmented worms)
arthropods (insects)
121
cleavage in protostomes
spiral - blastomere cells of upper tier sit in the grooves between the cells of the lower tier
122
gastrulation
morula - blastula - gastrula
123
what is gastrulation?
rearrangement of the cells of the blastula
124
invagination
cells at one pole of the blastula move inward
125
gastrula
hollow single layered blastula
126
where the cells invaginate
blastopore
127
3 layers in the germ layer
ectoderm - outer layer of the gastrula
endoderm - lines the embryonic digestive tract
mesoderm - partially fills the space between the endo and ectoderms
128
key body parts that form from ectoderm
epidermis of skin
nervous system
129
key body parts that form from endoderm
lining of digestive tract
lining of respiratory tract
lining of urethra
reproductive system
130
key body parts that form from mesoderm
skeletal system
muscular system
dermis of skin
131
three kinds of morphogenesis changes occurring with organogenesis
folds
splits
condensation/ clustering
132
first body part to take shape in chordates?
neural tube and notochord
133
what will the neural tube and notochord become?
spinal cord and backbone/vertebrate respectively
134
when does the notochord form?
when the mesoderm condenses
135
if a mother does not get enough folic acid in her diet how will this affect the baby?
neural tube defects - spina bifida
