The New Born Baby

Question 1

Evolution of mammals

Answer 1

Birth is a combination of mechanisms which are widespread among relatives - need to look at evolution of other mammals to understand humans

Question 2

What happened 65 million years ago?

Answer 2

There weren’t many mammals, this was the age of dinosaurs (relied on sun, cold blooded). An asteroid landed on the earth, dust settled and dinosaurs died out, leading to an increase of mammals, now more than 20 million mammals

Question 3

What is it called when there is in increase in mammals?

Answer 3

Adaptive graduation

Question 4

Why did the mammals survive?

Answer 4

Endothermy - warm blooded. This developed in order for us to function, the capacity to maintain body temperature despite changes in temperature, as long as they are given food

Live birth - they provide for their offspring (safety etc). Parenting is a consequence of evolutionary adaptations

Question 5

What are primates?

Answer 5

Similar behaviours (so same parenting styles)
200 species
Diverse group
Distinguished by their thumbs, nails, forward facing eyes

Question 6

How are primates different compared to other mammals?

Answer 6

Precocious (advanced)
eyes and ears not shut (carnivores, rodents)
rapid locomotor development
Altricial (slowly developing)
we are dependent on mother for up to 4 years (organgutans ween till 4 years)
longer childhood stages
delayed adolescence

Question 7

Similarities and differences of humans and chimps

Answer 7

Humans have the longest period of infancy, they aren’t qualitatively different to chimps but the end of their life is different. Chimps give birth throughout, humans have menopause

Question 8

What sensory capacities do new borns exhibit?

Answer 8

Touch - pain, temperature
Balance
Smell
Taste - salt, bitter, sweet, sour
Hearing - low frequencies
Vision - 20/400 at birth, 20/20 at 6 months

Question 9

What are some neonatal reflexes?

Answer 9

Vestigial - doesn’t serve any current purpose. e.g. stepping as can’t walk till 1

Question 10

Examples of neonatal reflexes

Answer 10

Grasping - keeping close proximity to the mother
Crawling
Tonic neck (when head turns, one arm extends)
Stepping (lift one leg, then other)
Moro
Most automatic, strong reflexes indicate a good CNS, most disappear with age

Question 11

Brain growth in man and chimpanzee

Answer 11

At birth, human brain is bigger and grows loads after birth, chimps doesn’t grow much. Ours is 3 times bigger, have to invest 25% of every calorie to our brain

Question 12

What affects post natal brain growth?

Answer 12

Glia
Myelination
Synaptogenesis

Question 13

Glia

Answer 13

Most neurons are present at birth but glia multiplies, they provide structural support, maintenance and insulate neutrons axons with myelin

Question 14

Myelination

Answer 14

Axon terminals and dendrites increase over the first year and make new connections
Formation of fatty sheaths around axons, speeds up electrical potentials
Unmyelinated axon - 1 per second
Myelinated axon - 10-100 per second
In CNS, oligondendrocytles lay down myelin
in peripheral, Schwann cells do it

Question 15

Synaptogenesis

Answer 15

Formation of new connections between neurons, connections grow in first year of life - similar in chimps
Broca’s area - cell bodies stay the same but there is growth in dendrites and axons