PSY320H1 Study Guide - Fall 2018, Comprehensive Midterm Notes - Earth, Solar Irradiance, Photosynthesis
PSY320H1
MIDTERM EXAM
STUDY GUIDE
Fall 2018
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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4. The high pressures and temperatures reached within protostars → nuclear fusion to create He
Stars
• Fusion reactions: H → He → Fe
• Supernova: When a very massive star runs out of fuel, a very energetic explosion occurs, so that elements heavier
than Fe are formed
o Star death → universe w heavier elements that mix with residual gas from Big Bang
• The sun is a 3rd or 4th generation star developed 5 buy. ago from a nebula that contained all 92 elements
• Planets developed from residual dust and gas surrounding the newel formed un
Formation of Planets
• The gas and dust from the protoplanetary nebula condensed into → planetesimals → protoplanets → true planets
• Inner, rocky planets made up of heavier elements: iron, magnesium, silicon and oxygen
• Outer, gaseous and icy planets made up of frozen gases and lighter elements: hydrogen (H), helium (He), methane
(CH4) and ammonium (NH3)
Evolution of the Earth: Geological Time (PRECAMBRIAN)
• PRECAMBRIAN (4 BILLION YEARS AGO): Hadean (No O2) → Archean (atmospheric changes) → Proterozoic
(transition to the modern world)
o The Archean Eon (3-8 -2.5 billion years ago)
• Intense green house effect caused by greater amounts of greenhouse gases in the atmosphere (e.g. 100
times more CO2 than today) that countered the effect of the faint young Sun
• First possible evidence of life (cyanobacteria)
• 3.4-3.5 Ga there were photosynthesis cyanobacteria which means before then (prior to 2.5 Ga)
photosynthetic organisms evolved that released oxygen into the environment
• Oxygen build up in our atmosphere and oceans changed surface conditions of our planet
o Proterozoic Eon (2.5-0.55 Ga)
• Large volumes of Fe formations were deposited (from O2) - marks transition between an
atmosphere/ocean with little oxygen to an atmosphere with abundant oxygen
• About 2 Ga ago eukaryotic cells appear (early forms were unicellular algae)
▪ MASSIVE BUILDUP OF O2 → 670 Ma complex shell-less invertebrates
Evolution of the Earth: Geological Time (CAMBRIAN)
• Phanerozoic (600 Ma): Paleozoic (high CO2 levels) → Mesozoic (highest CO2 & dino) → Cenozoic (age of the
mammals)
o Organisms with shells and boned evolved (visible life)
o The Paleozoic Era (545 Ma -245Ma):
• continents were scattered, following break-up of the supercontinent Rodina
• Continents drifted during most of Paleozoic; towards the end of the era (Permian) continents were
collected into a supercontinent called Pangaea
• Hot house - time of inlands seas and diversification of life
• First fish, shark, land planets, amphibians, reptiles,
• Paleozoic Era ended with the largest extinction event in the geological record
• Permian-Triassic Extinction (PT boundary): marks the transition from the Paleozoic Era to the
Mesozoic Era
• Greater than 90% of marine species lost
• greater than 70% of vertebrate land species lost
• only known mass extinction of insects as well
o The Mesozoic Era (245 Ma -65Ma)
• Pangea begin to break up
• End of Jurassic and cretaceous
• Hot house (Co2 reached a maximum)
• Age of reptiles & first mammals, birds, and flowering plants
• Cretaceous-Tertiary Extinction (KT boundary): marks the transition from the Mesozoic Era to the
Cenozoic Era
• End of dinosaurs (greater than 75% of all species lost)
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