Exam 2: Week 8 Flashcards
what are the human growth patterns? (3)
- In infancy the height velocity is high but in childhood the speed of growth slows down through juvenile
- In adolescence females will first increase height velocity and then males later
- Eventually stop growing in teens and early 20s
body tissue growth; components of it? (4)
the organism has an energy budget directed toward certain things during development
- Maintenance
- growth
- gene copies
- reproduction
average age of human weaning
2.5 years compared to 5 for chimps and 7.7 for orangutans
- Babies have a lot of brain growth ⇒ up to 5-6 years
- They also grow teeth before they are replaced later as adults
- The body doesn’t grow as much until adolescence
- Reproductive systems are kept on hold until about the age of 15-20
age at first birth for humans vs chimps?
19.5 vs 14.9
- menarche and first birth are much later than other apes
menarche
the age females first get their periods
why are human infants weaned early for their body size?
they retain small, weak milk teeth much longer than other apes ⇒ keep our teeth longer because we cook
what are major changes at adolescence? (9)
- bones
- muscle
- fat
- hair
- sweat
- oil
- blood
- sperm
- sex
what are changes in bone size at puberty?
- Women: wider hips ⇒ begin growing a little bit earlier than boys
- Men: broader shoulders, taller ⇒ grow faster and longer
why do men have broader shoulders?
Shoulders support larger arms which could increase boxing force
- We fight with our firsts more than other apes due to bipedalism
- Our bones in our hands and faces are more robust to withstand punching forces ⇒ reproductive competition
how does muscle change for men compared to women? (6)
- 50% more muscle mass in upper body
- 10-15% more muscle mass in lower body
- Denser, stronger bones, tendons and ligaments
- 30% greater lung volume per body mass ⇒ oxygen
- Larger heart
- Fewer white blood cells, more susceptible to infection from less energy put toward the immune system (men die at faster rates at every age)
T/F by 12 the average boy is stronger than his mother
true
when do males tend to be bigger than females?
with intense male-male competition for mates
how does fat differ in men vs women?
Men have 15-18% while women have 22-25%
- Breasts advertise fertility, nubility
- Fat provides important energy store for growing and feeding babies
what type of fat gives a rounded appearance to women’s bodies?
Subcutaneous fat
- curves of breasts, accentuates curves of hips
what type of hair are humans born with?
vellum hair covers body from birth ⇒ similar to chimps
how does vellus hair become terminal hair with puberty?
Under influence of androgens
- goes from no noticeable hair to genital hair, arm/leg hair, head hair, and other various places
what are possible uses of extra hair? (2)
- Visual signs of sexual maturity
- Retain glandular secretions (odors)
why would men need beards? (5)
- Visual signal of adult male status
- Retain glandular secretions
- Protect the face during fighting
- Exaggerate body size
- Visual signal of species identity
Eccrine sweat glands; main function?
are all over the body and excrete mainly water and salts; thermoregulation
Apocrine sweat glands; main function?
in the face, armpits, and genital area excreting complex fatty compounds ⇒ bacteria break these down and produce body odor; scent glands
during adolescence what gets clogged with appearance of zits?
sebaceous glands which often build up in the hair follicular canals
sebum
complex oily substances that makes hair waterproof (oily) ⇒ glands occur at base of hairs, eyelids, lips, nipples, labia, penis
- Exchanged during kissing
what happens to specifically females with blood production?
lining of the uterus being shed
- the ovaries produce eggs
- these are released into the fallopian tube at sexual maturity each month
- sperm swim up the tube and travel down together
- growth happens in the uterus where the baby is and lining will shed to prepare for pregnancy
what happens with sperm production for adolescent boys? Cell process?
spermatogenesis occurs via meiosis and these develop into sperm
- go from the scrotum up the tube and then into the penis where they leave the body