PSY320H1 Lecture Notes - Lecture 1: Phanerozoic, Hydrosphere, Supercontinent
Lecture 1
Environmental Science
• Environmental science is the study of:
o How the natural world works
o How the environment affects humans
• This includes enrichments the environment can provide for us such has health, mobility, leisure
o How humans affect the environment
• This includes the impacts humans have made which are a long-term threat on health and survival
• Environmental science has an integrated approach to addressing problems that can hopefully produce lasting solutions
• Environmental science: the pursuit of knowledge about the natural world (objective)
• Environmentalism: a social movement dedicated to protecting the natural world
The Earth System
• System: any assemblage or combination of interacting components (e.g. the human body)
• Earth has four major interacting parts, which flow of matter and energy between them;
1. Geosphere/lithosphere: rocks and sediments
i. the upper part of the solid earth, which interacts with the other component of the Earth System, is called
LITHOSPHERE
2. Atmosphere: the air made up of nitrogen, O2, CO2
i. Transfer of heat and light
3. Hydrosphere: the totality of earths water, including the cryosphere which is perennial frozen parts
4. Biosphere: all living organisms and recently deceased and decaying organic matter
• Ecosphere: the biosphere and its interactions with physical (includes non-living components)
• Anthroposphere = technosphere: encompasses parts of the earth modified by humans and interactions of the
anthroposphere with other subsystem of the earth = environmental science
Sources of Energy
• External energy from solar radiation → hydrologic cycle and circulation of atmosphere and oceans → erosion of land
surface
• Internal energy from radioactive decay in the earths interior → volcanism and lithospheric deformation
Global Change
• Global change: the modifications of the earth system's components and the interactions between these components,
both natural and human-induced
• There are 4 types of global change;
1. Gradual: takes place over long periods of time
2. Catastrophic: takes place rapidly
3. Unidirectional - evolution of solid earth, atmosphere
4. Cyclical - sea levels
• Great oxidation event is an example of a natural change → drastically altered the composition of the surface of the
earth
• Population grown is a human induced change and has driven our environmental impacts
o This is because humans need ENERGY (burning fossil fuels) & RESOURCES (food/land/farming) - human
population is still rising
• Few examples; deforestation, climate change, air & water pollution, acid rain
Formation & Evolution of The Universe
• The universe was created from a small dense conglomeration of matter and energy called a singularity which
exploded (BIG BANG)
• There were 4 main events that occurred after big bang [HNPN - he never picks Nesta]
1. Hot clouds containing only H (and a little He)
2. Gases clump into separate clouds called nebulae
3. Nebulae collapsed → protostars
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