PSY 4130 Lecture Notes - Lecture 2: Hominidae, Australopithecus
5 Jun 2018
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Lecture 2: Context & the Universe
Relative to the plane of Earths orbit, Earths axis is tilted. This tilt accounts for the seasons. In
the winter, the sun is low in the sky and the days are shorter, in the summer the sun is high and
the days are longer.
Stars: only visible at night or during the total eclipse of the sun, because during the day the
Suns light obscures the much dimmer light from other stars. Several centuries ago, humans saw
patterns among the starts in the sky. These patterns, formerly called asterisms are what we
know today as constellations. As the earth revolves around the Sun over one year, the
constellations above us are always visible. However our night view near the horizon changes.
Starts that are visible in the summer are not visible in the winter.
Because the nigh sky changes during the year, each constellation near the horizon is associated
with a particular season.
The deepest we have ever gone into the ocean is 10.97km, he deepest we have ever drilled into
the earth is 12.3km deep, despite the earth of the radius being 6378km.
We have barely scraped the surface of the planet we live on.
The Moon
Earth is accompanied in its orbit b the moon, which orbits the earth at an average distance of
385 000km, revolving around the earth once every 29.5 days.
• this effects gravitational pulls on the earth
• the oceans do move, bulging out towards the moon
• low tide occurs at 90* of the Earth-Moon axis
• shorelines undergo a regular submersion by, and emergence from, the ocean
• it is believed that this cycle was instrumental in the movement of life from sea to land
Because of the earths axis tilt and the development of seasons, certain parts of the year are
better for growing some crops then other times of the year.
Precursors to humans
Anthropology tells us that humans are related to the great apes — perhaps especially to the
chimpanzee, with which we share 97% of our DNA. Paleoanthropological evidence – that is,
from anthropology in ancient times – identifies several species that seem to be intermediate in
tie etee our aestor ad Hoo sapies, our speies.
Lucy: 40% of the skeleton of a young Australopithecus afarensis female (a hominin) was
reconstructed. The skeleton dates from 3.2 million years ago.
she walked upright
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Relative to the plane of earths orbit, earths axis is tilted. In the winter, the sun is low in the sky and the days are shorter, in the summer the sun is high and the days are longer. Stars: only visible at night or during the total eclipse of the sun, because during the day the. Suns light obscures the much dimmer light from other stars. Several centuries ago, humans saw patterns among the starts in the sky. These patterns, formerly called asterisms are what we know today as constellations. As the earth revolves around the sun over one year, the constellations above us are always visible. However our night view near the horizon changes. Starts that are visible in the summer are not visible in the winter. Because the nigh sky changes during the year, each constellation near the horizon is associated with a particular season.
