This lecture covered several key topics relating to evolution and human development: 1. The professor discussed how environment, phenotype, and genotype can influence each other and how any trait is the result of both nature and nurture. 2. It was explained that while individuals have infinite genetic possibilities, the phenotype that develops represents a restricted set of those possibilities based on both genes and the environment. 3. The lecture outlined how natural selection begins at conception and continues through maturation and learning, shaping development based on an organism's ability to survive and reproduce in its environment.

1. [_,J
..
e_
Classi cal Notes
.oDtr lLo
ogr_r{ v,n 9-co-Jroo
F 9 00-l oo ANNOTJNCEME,NTS HDE 1OOA
PHobr, _ 752-7638 Lecture 3
Page 1 of 3
Announccments: There are no ilnnouncements for todav.
iI
Previous Lecture: In the previous lecfure, Professor Harper reviewed ideas about theories
briefly and then discussed the basic ideas behind evolution- 'fhe main ideas liom .the lccture
were that environment, phenotype and genotype can all affect each other, and that any given trait
exprcssed in a phenotype is a result of environment and genotype (nurture AND naturc).
This Leclure:
tL
rq
d, o Outline on chalkboard:
; I. Evolution
E (] a. Organism - Environment
tx i.Genorype + Phenotype
J A
b. Life Cycle + Selection
I. Every individual has infinite possibilities in traits.
a. Environment AND biology determine phenotype (what traits are expressed).
Nurture AND nature are responsible- It is not a question of either/or.
i. If the genes aren't there for any given b'ait, it is not possible for thz t
. to be expressed in the phenotype; similarly if the environment to supytrrt
that given hait is missing, that trait is still not possible.
b- E-g. Of protein coding genes in humans, 2%o are NOT shared with chirnpanzees.
i. Although being human is genetic, we still share our genes with so many
other species. This suggests that there are many possibilities within the
world of genetics/biology !
II Every cell in the body could be used to clone that individual, because every cell
originates with infinite possibilities (e-g. stem cells originally have infinire possibilities
before they specialize to one specific type of cell).
a. However, one cannot express ALL traits at once! Too many cells/uncontrolled
& growth are cancer-
rrl
v III. Phenotype:
F a.
Co-action between genes and environment.
b.
Represents a somewhat restricted possibility-
P i- Only one of many possibilities is expressed in any given trait within the
o
z phenotype-
IV. Natural selection:
a. Starts at conception!
b- Azygote has to be able to survive; it needs to be genetically sou:rd and have the
proper environmenl to grow in.
{ i. E.g- thc sperm and ovum must function properly to crcate a lertilized egg
OI
ol in the first place!
il
Maturation:
a. Typical development steps of a species.
VI. Innate:
.a* a. Usually means "genetically programmcd" (not learned)-
:+
,t)

2. HDE 1OOA
Lecture 3
Page 2 of 3
b. But humans zero-in/specialize traits throughout development.
i. Therefore, not every "innate" trait is "inevitable".
c. Innate traits depend on the environmental input involved-
d. There me limits to what we are and what we can be.
Vil. Learning:
a. Even learning is limited.
i. Species learn different things than other species, and they may have a
different learning process all together.
b. Example of limited leaming: Human nervous system:
i. Over produces!
ii. Eventually some branches/neurons are pruned away.
iii. Stimulation is required to maintain brain power ("use it or lose it").
c. Body systems require input and stimuli to function at all.
VIII" Culture:
a. Myth: culture sets humans apart from other animal species; humans are unique!
b. Culture can be shared beliefs/morals/norms which are shared within a population
of people. This can also include language, physical artifacts, and eating habits.
i. Transmitted in a behavioral way.
c. Every species has "social behavior", which can be considered culture.
i. This social behavior changes based on environment.
d. Therefore, humans are NOT unique compared to other species
e. Examples:
i. Fish are just as "flexible" as humans (if not more so).
1. Some species of fish can change their sex as a form of firnctioning
social behavior.
ii- There are different local language dialects within animal species (iust like
humans).
1. E.g. birds, monkeys, and prairie dogs.
iii. One population of a bird species in a British town learned how to drink
milk that was delivered to houses by pecking t}rough the caps before the
owners went to retrieve the bottles. This is an example of a local
population displaying culture and learning
iv. One population of Japanese Macaques (monkeys) Iearned to wash sweet
potatoes before eating them, even though sweet potatoes were not native
to their area. This is another example of culture within a species.
l. This tradition was passed on throughout the popuration (like
humans!).
IX. Environment:
a. Includes culture.
b. "cultural environment" (e.g. agricultural practices) affects phenotype within
species!
i. Example: lactose intolerance.
1. Most adults worldwide are lactose intolerant because when they
are weaned as babies their bodies no longer need to produce the
enzame (lactase) that digests lactose in milk and dairy products.

3. HDE 1OOA
Lecture 3
Page 3 of 3
2. In Westemcultures, many adults drink milk and are not lactose
intolerant. over time a tolerance to lactose has been built up-
X. Humans are just another species of animal.
a. we are just as dependent on an environment as other species.
b. If so, then what is important in understanding humans?? What sets us apart from
other animal species?
i. Every human culture:
1 Recognizes kinship.
2. Has religion (almost every culture).
3. Prizes health, wealth and power (size is often a mezrsure of these).
4. Humans are very different within groups.
5. Humans are complex organisms.
a- Disorders require multiple insertions and deletions in rnany
different genes.
XI. Infants:
a. Born with cerlain reflexes.
i. Reflexes are involuntary motor responses (like the knee-jerk reflex).
ii- Spinal link between brain signal and motor muscles (the spinal cord is
connected to the brain).
iii. Thought to be "innate', (unlearned).
1. What about ..blink" reflex?
a. It is often involuntary, but can also be controlled.
iv' We cannot control EVERY reflex! We wouldn't survive. E.g. smooth
muscle refl exes, respiratory refl exes, digestion.