Neur 2200: Lecture 2

Front 1

What is Materialism?

Back 1

-Theory that states behaviour can be fully explained by the workings of the nervous system without explanatory recourse to an immaterial mind.

Front 2

What 3 pieces of evidence show how species evolve?

Back 2

-1) Fossil records

-2) Structural similarities

-3) Programs of selective breeding

Front 3

What is natural selection?

Back 3

-Explanation of how new species evolve and existing spaces change over time.

-Variations in traits that increase fitness will increase the probability of that species' survival.

-Differential success in the reproductionof different characteristics results form the interaction of organisms withtheir environment.

Front 4

What is sexual selection?

Back 4

-Each sex has anatomical and behavioural features that favour reproductive success. Theses features are meant to attract the opposite sex.

-Ex: male peacocks and their plumage.

Front 5

How are traits selected naturally?

Back 5

-1) Appearance of new trait (via mutation/variance, ex: giraffe longer neck)

-2) Adaptive trait (helps them eat)

-3) Increases chance of survival

-4) Trait passed on to offspring

Front 6

What is taxonomy?

Back 6

-The branch of biology concerned with naming and classifying species. Groups of organisms with common characteristics.

-This is useful for helping us trace the evolution of brain cells and the brain.

Front 7

What is a cladogram ("branch")?

Back 7

-Displays groups of related organisms as branches on a tree.

-Branch order represents how the groups are related evolutionarily as well as the traits that distinguish them.

-Left-to-right: most recently evolved organism/trait is farthest to the right.

Front 8

What is a nerve net and ganglia?

Back 8

-1) Nerve net: simple nervous system, organized as a net with no brain.

-Ganglia: structures that resombre and function somewhat like a brain.

Front 9

What 2 features distinguish the chordates?

Back 9

-1) Nervous system is crossed.

-2) Chordate spinal cord lies behind heart and gut.

Front 10

Describe the differences in our 4 ancestors.

Back 10

-Australopithecines are the most recent and were hominids that made and used tools. This reduced the necessity for large jaws/teeth which became steadily smaller.

-As H. Habilis evolved, brains became larger and faces smaller.

-H. erectus made elaborate tools, used fire, hunted, and expanded their area over 3 continents.

-H. sapiens brain volume reaches modern levels.

Front 11

How have humans brains evolved?

Back 11

-They increased in size, most of this being in the cerebrum which resulted in increased convolutions of the brain and greater surface area, as it allows for more neurons in a given space.

Front 12

What is Jerison's Principle of Proper Mass?

Back 12

-His principle stated that species with more complex behaviours will possess relatively larger brains.

-He developed an index of brain size to all comparisons among different species. Body size was used to predict brain size.

-Developed the EQ (encephalization quotient)

Front 13

What is the Encephalization Quotient?

Back 13

-Measure of relative brain size from ratio of actual brain size to predicted brain size based on a given body size.

-This was considered a rough measure of intelligence.

-Humans have the largest.

Front 14

What are 3 reasons the hominid brain enlarged?

Back 14

-1) Primate Lifestyle

-2) Changes in Hominid Physiology (2 hypotheses)

-3) Neoteny

Front 15

Explain how primate lifestyle enlarged the hominid brain.

Back 15

-The foraging behaviour of primates is more complex than other animals. Ex: if you are eating fruit, you need good sensory, memory, and spatial skills. It is more difficult than eating grass.

-You have to seek out fruit, remember where it is, make distinctions, check what is ripe or spoiled, etc.

Front 16

Explain how changes in hominid physiology enlarged the hominid brain in terms of the radiator hypothesis.

Back 16

-The more active the brain is, the more heat it generates, thus skulls had more widely dispersed blow flow and allowed for more blood flow to cool down the brain.

-More dispersed blood circulation allowed for bettering cooling which thus allowed for the brain to grow.

Front 17

Explain how changes in hominid physiology enlarged the hominid brain in terms of Stedman and colleagues hypothesis.

Back 17

-They stated that a genetic mutation allowed for smaller facial muscles and bones which caused a change in diet.

-Change in diet let us eat more things like berries and fish which allowed for encephalization.

Front 18

Explained how neoteny enlarged the hominid brain?

Back 18

-Neotenization is a theory based on observation that older modern humans resemble juveniles of our ancestors. This suggests that stages of maturation have been slowed down.

-Slowing rate of maturation allows more brain cells to be produced.

Front 19

What are problems with measuring larger brains to see if they are more intelligent?

Back 19

-1) It is difficult to make brain-behaviour comparisons between members within the same species.

-2) How does one measure brain size? We'd have to control for skull thickness, volume vs weight, and control for body weight.

-3) How do we account for factors like age, physical health, and brain damage?

-4) There is a problem of causality, does bigger brain cause greater intelligence, vice versa, or extra variables?

Front 20

What is a problem with measuring intelligence?

Back 20

-We don't know how to measure intelligence!

-People vary enormously in their individual abilities depending on the task.

-You can't just measure intelligence based on a score on a test.

-Ex: Person A is good at math but bad at spatial skills, Person B is opposite, who is more intelligent?

Front 21

What is the relationship between culture and our brains?

Back 21

-Our large brains have allowed us to develop a rich culture.

-Complex learned behaviours that are passed down generations through teaching and learning.

-Most of our behaviour is learned from culture.

-Our brains are very flexible to learning.

Front 22

What are some costs of having a bigger brain?

Back 22

-Long gestation period of this brain from utero until adolescence.

-Brains are metabolically costly using a lot of energy, glucose, etc. to fuel necessary equipment to make communication happen.

-Complex genes are vulnerable to mutation.

-We take a long time to learn how to be independent and autonomous from parents.

Front 23

What are some benefits?

Back 23

-increased survival and ability for interaction.

-Innovative behaviour, use of tools, and social learning.

-Predicts success in a novel environment.

-Sexual selection pressures for ability to attract attention, artistry, and creativity may lead to increased brain size. More creative you are to attract your mate, the better the likelihood of your survival.