Week 12: Pregnancy/Lactation and Meat/Cooking Flashcards
(105 cards)
1
Q
where does fertilization happen?
A
if fertilization happens it will be in the fallopian tubes
- migrates from the fallopian tube to the uterus and continues growing
2
Q
where does the fertilized zygote implant? What’s it called when it implants?
A
into the thickened wall of the uterus as a blastocyst
3
Q
Blastocyst
A
germinating embryo in a bladder or pouch
- Pre-implantation embryo
- 70-150 cells
- 5 days old
- Source of embryonic stem cells ⇒ can be programmed during development trajectory
4
Q
Trophoblast
A
means nourishment which gives rise to the placenta
5
Q
Embryoblast
A
the embryo/fetus which develops into the baby
6
Q
Endometrium
A
(within uterus) implantation within the mothers uterus and is the lining of the uterus
- This layer is shed during menstruation without fertilization
- above the endometrium there is the basal layer which stays throughout the cycle
7
Q
Human chorionic gonadotropin (hCG)
A
peptide hormone made by placenta after implantation (6-12 days) and stimulates the gonads (gonadotropin) used in early pregnancy detection
- Part of communication between mother and developing embryo
8
Q
what is used for pregnancy detection? How long can you have false negatives for?
A
hCG as it increases after implantation
- False negatives possible up to 3 weeks after intercourse even leading to pregnancy
9
Q
Placentation
A
attaches to baby via umbilical cord and feeds/nourishes baby ⇒ meaning flat cake (red thickened layer)
10
Q
what is the purpose of the placenta?
A
Disposes of toxic waste ⇒ by-products of metabolic waste that need to be disposed of
- Fetuses cannot excrete urine and feces but the mother can
- Occurs in placental mammals ⇒ not monotremes or marsupials, sharks, etc.
11
Q
purpose of the placental barrier?
A
No direct mixing of maternal and fetal blood
- Some substances do cross the barrier
12
Q
what substances cross the placental barrier? (4)
A
- Alcohol
- Anesthetics used in medical childbirth
- Chemicals from cigarette smoke
- Some viruses
13
Q
what are the types of placentation? (3) what type do humans have?
A
- epitheliochorial (cows/pigs/horses)
- endotheliochorial (dogs/cats)
- hemochorial (humans)
14
Q
Hemochorial placentation
A
bathed in a lake of maternal blood to permit more efficient transfer of nutrients (for big brain)
- From greek blood and chorion = skin/fetal membrane
14
Q
characteristics of hemochorial placentation? (2)
A
- swamp of maternal blood on one side and fetal blood in a vessel on the other side
- Much more limited than the other types of placentation
15
Q
what percentage of pregnancies are lost after implantation? before clinical signs of pregnancy?
A
31%; 2/3
- Total rate of loss probably higher, as not all embryos make it to implantation
16
Q
why are so many pregnancies lost early? (2)
A
- Early loss enables a mother to avoid investment in unviable offspring => Genetic problems like mitonuclear mismatch or developmental problems
- mothers could also have a loss of energy which triggers fetal loss => 14% of baboon pregnancies end in loss and 40% of red tailed monkey pregnancies end in loss
17
Q
when does estrogen shoot up during pregnancy?
A
3-4 (early on)
- at birth estrogen tanks
18
Q
what is estrogen sensitive to?
A
mothers nutritional status
19
Q
fetal tolerance
A
tolerance by the mothers body of the fetus
20
Q
why does fetal tolerance occur?
A
A fetus is not genetically identical to the mother
- Sometimes the foreign DNA can be attacked by the immune system
- The mothers immune system needs to be suppressed for the body to tolerate the fetus which is not genetically identical
21
Q
what becomes abundant to kill bacteria, fungi, and respond to inflammation
A
neutrophils
- Implantation increases inflammation to get thickened uterine lining
22
Q
what do tregs and bregs do
A
suppress immune respones which are elevated and then decrease over time
23
Q
what do lymphocytes do?
A
attack disease cells and infections
24
what is the TH2 response? TH1?
the innate response during pregnancy; TH1 response is proinflammatory and kills intracellular parasites
- TH2 increases and TH1 decreases during pregnancy
25
do T cells, NK cells, and B cells increase or decrease during pregnancy?
decrease
26
what happens to lymphocytes during pregnancy and after?
Lymphocytes decrease until birth and then increase and become stabilized
27
what patterns do Tsimane and American women show for lymphocytes during pregnancy?
pretty much the same pattern
- Tsimane live in a parasite rich environment and show different patterns of immune activation than ppl in the USA
28
what patterns do Tsimane and American women show for neutrophils during pregnancy?
huge bump in neutrophils in the US while the Tsimane have a more neutral level circulating in the bloodstream during pregnancy
29
why do women have morning sickness? (aka nausea and vomiting in pregnancy [NVP])
- The food aversions, nausea, and vomiting of pregnancy sickness evolved during the course of human evolution to protect the embryo against maternal ingestion of the wide array of teratogens (toxins that cause birth defects) and abortifacients (toxins that induce abortions) abundant in natural foods
- Pregnancy sickness represents a lowering of the usually human threshold of tolerance to toxins in order to compensate for the extreme vulnerability of the embryo to toxins during organogenesis
30
when is the CNS primarily developing? Does this correspond with peak of NVP?
weeks 5-20; corresponds with the peak of maternal nausea and vomiting
31
are people who don't have NVP more or less likely to have a miscarriage or stillbirth? Examples of foods with toxins?
people who are pregnant and do not have morning sickness are more likely to have a miscarriage or stillbirth
- Many pregnant women have aversions during their first trimester => Fish, meat, poultry, and eggs can have the most concentrated toxins
32
what does the infant look like at 6, 10, 20, and 40 weeks?
- at week 6 the fetus looks like a fish due to common developmental pathways
- By week 10 the uterus is expanding with the fetus and the head has gotten bigger ⇒ still a small amount of tail
- By week 20 it looks more like our species
- By week 40 it's pretty much a full form infant
33
what are costs to the women's body for having an infant inside of her?
shoves organs around
- both the lungs and the bladder have a harder time expanding
- The infant is pressed against the spinal column
- The colon is being pushed against the back ⇒ why we have an enema so the infant doesn't come out with poop
- It takes time for the organs to come back to their normal locations
34
characteristics of chimpanzee birth? (4)
- Primates tend to hide when giving birth because they are vulnerable
- Most primates give birth early in the day when it is still dark out
- All females gave birth in day nests
- Mothers delivered in a variety of positions => tripodal standing, squatting, lying on her side
35
what is labor for chimps like compared to humans?
Labour lasted from 40 minutes to 7.5+ hours
- Compared to an average of 16 hours total labor and 3-5 hours of active labor for humans
36
T/F female apes (Gombe) face harassment?
True
- Siblings/juveniles begging to feed on the placenta
- Baboons attempting to take the placenta
- Adult females joining together in apparent infanticide attempts
37
what is different about human birth compared to other mammalian births?
pregnant humans usually require assistance to give birth
- Assistance of doctor or nurse/midwife greatly reduces risk of death for mom and baby
- Supportive companions are also important => father/relatives/doula
38
how does support (doula's) change women's labor? (3)
- Shorter labor ⇒ 8.7 vs 19.3 hours
- Lower incidence of problems
- More awake, affectionate to infant after birth
39
what would happen if another chimpanzee female was present during
Presence of unrelated female during birth would greatly stress a chimpanzee mother
40
why would assistant birth happen with human mothers?
probably an ancient feature of human lineage
- adaptation to giving birth to large brained babies
41
what are the different types of parental care options for species? (4)
- None ⇒ insects, fish, herps
- Lay eggs in food stash ⇒ dung beetles, wasps, flies
- Protect young after hatching ⇒ alligators, pythons, cichlid fish
- Feed the young ⇒ bees, ants, birds, mammals
42
what are the 2 options for feeding offspring?
1. direct provisioning
2. converting food to secretions
43
what animals are examples of direct provisioning?
- Most birds
- Wolves and other canids regurgitate meat
44
what animals are examples of converting food to secretions? (3)
- Some amphibians (Caecilians)
- Pigeons, flamingos, penguins
- Mammals
45
lactation
production of milk
- Defining trait of mammals
- All female mammals nurse their young
46
synapsid
single hole apse in skull behind eye ⇒ mammals are synapsids
- early synapsids are also called mammal-like reptiles and probably had hard eggs
- Flourished before the dinosaurs
- Permian period 300-250 MYA
47
when did internal fertilization occur?
about 350 MYA
48
when did hair and milk occur?
about 250 MYA
49
when did live birth and nipples occur?
about 125 MYA
50
when did placentation occur?
100 MYA
51
when did infant carrying occur for primates?
50-100 MYA
52
what do internal fertilization, hair/milk, live birth, placentation, and infant carrying all relate to?
female investment in parental care
- all of these are energetically costly
53
what did mammary glands develop from?
glands of early synapsids
- Probably apocrine glands associated with hair
- Initially served to keep egg moist ⇒ platypus, echidna
- Eventually began nourishing young
54
apocrine glands
portion of cell buds off with secretion
- Found in armpits, nipples, and groin
- Some sweat glands, mammary glands
55
merocrine (eccrine) glands
secretion released from cells ⇒ most sweat glands
56
how do the budded off portions of the apocrine cells get produced?
conversion of food used to produce ATP which is then used to produce budded off portions of the apocrine cells
- part of costliness is because they are regenerated
57
what are reasons/components for lactation? (4)
- Lactation involves inefficiencies
- Good if food supplies are unpredictable
- Easier to transport fat than food
- Programming
58
why is lactation inefficient? (2)
- Takes time to make milk
- Some energy is lost in transforming food into fat reserves and milk
59
how is milk used when food is unpredictable?
- Store food as fat when abundant
- Turn into milk as needed
60
what programs lactation?
hormones, microbes, and microbe foods affect groth rates, temperament, immune function
- Status of environment
- Status of the mother ⇒ mother is passing antibodies to the infant which tells the infant what pathogens are in the environment; she also passes cortisol which programs sensitivity to stress in the environment
61
are there differences among human populations relating to innate immunity?
no
62
Innate immunity
pre-programmed response to certain types of pathogens
63
adaptive immunity; does this vary?
what happens when you are exposed and then you develop resistance to a pathogen ⇒ adapt as you go along and get exposed to new things
- acquired immunities varies among populations depending on what pathogens the mom is exposed to along her lifetime
64
does maternal milk vary across human populations?
yes
- maternal milk varies in the composition of adaptive immune proteins ⇒ mom passes on her acquired immunities
65
how does human milk compare to other primates?
apes have a low protein content in the milk ⇒ some outliers
- Fat content across ape species is highly variable
- The most protein content is strepsirrhines
66
what is protein composed of
amino acids
- to grow we need amino acids ⇒ important for nutrition and growth
67
why do ape infants grow slowly?
Protein is hard to access and expensive => the shorter the growth period the more protein is needed
- fat is the most calorie dense nutrient we can consume which provides energy for offspring
68
colostrum; properties? (3)
Produced during first 2 weeks after birth
- High in carbohydrates, proteins
- Low in fats
- Contains antibodies, immunoglobulins
69
what is special about colostrum?
Right proportion of fats, proteins, sugars for human baby (or whatever other baby is being fed per population)
- Composition and amount naturally adjusted based on baby’s needs and moms reproductive future
70
what are benefits of breastfeeding? (5)
- No refrigeration required
- Always ready when needed
- Sterile and reduces baby's risk of disease => Formula made from powder and water is risky if water supply is contaminated
- Natural birth spaces
- Free ⇒ compared to formula
71
how does breastfeeding delay conception sometimes?
- Suppresses ovulation
- Not a reliable contraceptive, especially if moms diet is rich in energy and activity levels are low
72
what are disadvantages of breastfeeding? (4)
- Often difficult to establish ⇒ even in HG communities b/c it can be painful or crack nipples/cause mastitis
- Flow might be insufficient to support infant growth
- Some women may be uncomfortable breastfeeding in public because breasts are highly sexualized in many countries
- Difficult to maintain when mom goes back to work
73
What % of low income mothers breastfeed compared to high income women? at 6 months of nursing?
Only 56% of low income breastfed at home compared to 78% of high income women
- Only 14% were still nursing at 6 months compared to 18% of high income women
74
Lactational amenorrhea
condition where the new mother delays a return to cycling
- ovarian function is finely tuned to permit conception only when sufficient energy is available ⇒ this can lead to higher levels of unsuccessful pregnancies
75
how much calories does milk require to produce a day?
700 kcal/day
76
what is energy flux useful for predicting?
amenorrhea or when cycling will fail
- ⅓ of women’s energy flux ⇒ human bodies are sensitive to energy flux and it better predicts amenorrhea than low energy inputs on its own
- energy intensive milk production suppresses ovarian function
77
when does ovarian function resume again?
after supplementary feeding begins ⇒ soft adult foods
- pregnancy can occur while nursing but depends on intensity of nursing and how much mother is eating and exercising
78
Male provisioning
males providing food for offspring
79
examples of species with male provisioners?
- Many birds => Raptors, penguins, herons, pinyon jays
- Few mammals => Humans, tamarins/marmosets, wolves, cape hunting dogs, meerkats
80
what limits male investment in offspring?
Paternity certainty
- No genetic benefit in feeding some other guys babies
81
when do males engage in more paternal care?
More paternal care in species with high paternity certainty
82
what promotes paternity certainty for humans? (3)
- More monogamous marriage ⇒ seen across mammals
- Psychological mechanisms that promote more exclusive mating
- Social mechanisms for mate guarding
83
what are examples of social mate guarding mechanisms?
religious customs, gossip, culture of honor (fighting/reputation and women’s sexual chastity)
84
what is the rate of extra pair paternity?
quite low ⇒ about 1% aside from certain groups
85
what groups have high extra pair paternity?
- low income classes
Emerging in the late 1800s relates to urbanization and low SES
86
maternal care is close to _____ but paternal care is _____
obligatory; contingent
87
why is paternal care common in birds but rare in mammals?
1. Birds lay eggs
- Dad can contribute by sitting on eggs, feeding chicks
- Mom can abandon clutch if dad doesn’t help out, so dad has an incentive to do his share ⇒ in species where both parents are necessary to rear young moms have bargaining power
2. Mammals gestate and lactate
- Females already have massive investment in young
- Easy for dad to let mom do all the work
- Harder for dad to contribute ⇒ no body part to produce food
- Male care more common in species that hunt and can carry food
88
do men hunt to just show off?
new studies suggest men do actually hunt optimally ⇒ men direct meat strategically toward their families
- mom forages less with baby and dad provisions more when baby is young
- dad provision more when babies are young
89
what is the difference between male and female production?
Husbands produce more when they have babies under 1 year old ⇒ 2,000 kcals per day
- moms forage less with babies but will forage more later on in life
- production of meat brought in by men is much larger than that of women ⇒ tends to be a greater proportion of the diet than what women bring in
- hunting by men usually contributes the majority of each days calories
90
what amount of resting metabolic energy to brain take up daily for humans? Other primates?
- 25% of resting metabolic rate for adult humans
- 8-9% for most primates
91
Expensive tissue hypothesis
argues there’s a trade off between brains and other costly tissues such as muscle and guts
- More recent work finds little evidence of trade offs among organs in mammals, but still, brain needs energy to grow and operate
92
how much energy do babies use daily for their brain?
Newborn babies use 87% of their energy
93
how do humans pay for their big brains in HG communities?
Men drive evolution in this case => high risk, high gain resource
- dangerous for small bodies animal to acquire big game ⇒ humans are small in comparison
94
cooking hypothesis
cooking enables humans to extract more nutrients from the environment with less digestive effort
- Cooking is universal in modern humans ⇒ we have coevolved so much that we need it
- Externalizes our stomachs
- Should result in anatomical changes detectable in fossil record
95
advantages of cooking? (2)
- reduces digestive effort
- increases available energy
96
how does cooking reduce digestive effort? (4)
- Destroys husks, other barriers
- Easier to chew
- less wear on teeth
- Less processing needed in gut
97
how does cooking increase energy? (2)
- Bursts cell walls, releases cell contents
- Modifies molecular structure, making starch and other components more digestible
98
what were fossil signs of cooking? (2)
- signals of decreased digestive effort => Smaller teeth and Smaller gut
- signals of increased energy => Larger female body size and Larger brain
99
do apes prefer cooked food?
yes
100
what are the problems with early cooking hypothesis?
sparse early evidence of controlled fire (more studies needed)
- Gesher Benot Ya’aqov Israel: lakeside fires from 690,000-790,000
- Wonderwerk South Africa: evidence of campfires from 1 million years ago
- Koobi fora and chesowanja Kenya: suggestive evidence from 1.5 MYA
101
what are the effects of simple food processing in comparison with chimpanzees?
chimpanzees spend about 6 hours per day chewing their food
102
what types of externalized "teeth" do humans use?
stones for pounding, grinding, slicing
- Humans use digestion ⇒ cooking to obtain more energy in less time
103
how much benefit is gained from simple food processing alone?
simply slicing meat and pounding vegetables, a hominin would be able to reduce the number of chews they use by 17%
104
end card
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