- Cladogram: a graph that shows the relative time of origins of various closely
related groups, distinguishing as it goes forward one or more differing
characteristic or trait.
Enhanced depth perception
Females only have one baby and spend a lot of time caring for young
Taller (less differences in height due to gender)
Bipedal (forward posture)
Travellers (have populated most habitable continent).
Change in hand structure allowed for tool use
Changes in tooth structure (massive reduction in jaw size)
Changes in brain size (larger, more complex)
Why study nonhuman animals?
- There are many similarities between the two
Chimps: physical structure, facial expressions, and physical stature,
brains are sim. In structure and appearance, social living, tool use, and
Rats: cortical structure is sim. To humans.
Relatively simple nervous systems are good to study: quicker to study,
and factors can be isolated more easily and because evolutionarily older
present day animals resemble a common ancestor closely enough to
stand for it.
Genes: are the functional units that control the transmission and
expression of traits from one generation to the next.
Questions addressed by studying nonhuman animals
Understanding brain mechanism
- Homeobox genes: similar genes.
- Segmentation of the human nervous system into spinal cord, brainstem and
forebrain is produced by genes discovered in fruit flies
- Mutations: slight alterations from one species to the next
Designing Animal Models
- Recreate a neurological disorder in an animal, manipulate multiple variables
to understand the cause and come up with treatments, - Parkinson’s disease: associated with aging, voluntary movement, balance
problems, tremors of the head, hands and limbs. The models of this disease
have been developed in the mouse, rat and monkey
Describing evolutionary adaptations
- How the mammalian brain and behaviour evolved progresses in 3 ways:
1) Experiments with animals show how the environment shaped its brain
and behaviour. Each species evolved from some common ancestor.
2) Commonalities tell us what we inherited in common with other animals.
3) Shows how individual differences arose.
- Figure 2.3
Use of a quasi-evolutionary sequence
- Quasi- evolutionary lineage: a hypothetical sequence of animals that
represent consecutive stages I evolutionary history. (What humans have
different from other species is a large parietal lobe).
- (Figure 2.4)
- Striate cortex: primary visual cortex with a striped appearance.
Hominid Evolution (humans are the only ones still living)
Skulls: indicate brain structure
Habitat and tools: insight into behaviour
Morphological reconstruction: can assume what an ancestors body
looked like and measured to. (Figure 2.5)
Biochemical and genetic research
Amino acid sequence of a protein in one species can be compared to
another species. Used as a molecular clock to determine how long ago
they lived. There is roughly one change every 2.5 million years.
Can also be determined by analyzing their DNA.
Chimps share 99% of our genes
Genome: full set of genes of a species.
- Jane goodall: studied chimps. They have rich manual, facial, and vocal
capabilities. They use tools for defense and to obtain food and water. Males
go to war for territory. They eat both vegetables and meat. Good travellers.
Stages of Human Evolution
Steps of hominid evolution:
1) Upright posture in which hands are free
2) Extensive tool use
3) Traveling life style
4) Elaborate culture
- (Figure 2.6 A&B) Australopithecus: upright posture
- Eastern Africa and Ethiopia
- Yvete coppers: the “east side theory” climate change caused the hominid
lineage to diverge from the ape. The Great Rift Valley was a wetland, which