slifsci midterm crash course

Earth

• third planet from the sun

• Only one which hosts life

• Surface us mainly water

• Tilted

• Not perfectly round

  • Squished ball that bulges at the equator

  • Theres an imaginary line or an axis between the North and South pole

• You can fit a million of this in the Sun!!

• Days on here are getting longer!!

Age of the Earth

4.543 billion years

Speed of Earth’s rotation

1000 mph

Pangea

• super continent (around 250 million years ago)

  • 7 continents after 4.6 million years (drifted apart bc of tectonic plates → continental drift theory)

• At its beginning, Earth was extremely hot and full of magma and after millions of years it cooled down and liquids formed

Gravity

• causes the Earth’s spinning (effect nun is yung “bulge”)

• Invisible force that attracts forces to each other!

• Force that pulls things towards the Earth and stops us from floating into space!

• Anything that has mass also has this force

  • But bc of Earth’s size, its force is stronger compared to our own

Theory

Thought our explanation for observations of the natural world that had been constructed using the scientific method

Astronomy

Scientific study of the stars, planets, and other natural objects in space

Universe

Vast space that comprises trillions of galaxies and everything that exists → including space and dark matter

galaxy

Vast cosmic islands o stars, gas, dust, and dark matter held tgt by gravity

Electromagnetic radiation

A form of energy that includes radio waves, microwaves, x-rays, gamma rays, and visible light

Creationism

• biblical theory

• & days of creation → genesis 1:1

Scientific

• big bang theory

• Inflation theory

• Oscillating universe theory

• Steady state theory

Big Bang Theory

• by Goerges Lemaitre (1931) → SUPPORTED BY EDWIN HUBBLE (noticed that galaxies are moving away from us)

• The universe began from a very small, hot, and dense point around 13.8 billion years ago and has been expanding ever since

Evidence

• redshift of galaxies

• Cosmic microwave background

• Abundance of light elements

Redshift of galaxies

• evidence of bbt

• By edwin hubble

• Galaxies are moving apart (expansion)

Cosmic Microwave Background

• tira-tirang radiation from BBT

• Arno Penzias and Robert Wilson (1965)

Abundance of light elements

• hydrogen and helium matches predictions from Big Bang Model

Inflation Theory

• Alan Guth → 1980s

• After the BBT (within a fraction of a second) the universe went a rapid, exponential expansion much faster than the speed of light

• Added to BBT

  • To explain why the universe looks so uniform (same temp everywhere) and why its not flat

Evidence

• tiny temp fluctuations in the CMB → observed by satellites like WMAP and Planck → match the predictions of inflation

• Explains the large-scale structure of the universe (why galaxies are distributed in certain patterns)

Oscillating theory

• alexander friedmann → 1920s

• The universe expands, then contracts (Big Crunch), and this cycle may repeat forever (cosmic heartbeat).

• Suggests no true beginning or end-just endless cycles. 

• No current evidence of the universe slowing down enough to collapse.

• Recent observations show the universe’s expansion is speeding up, not slowing down-so a “crunch” seems unlikely for now.

Steady State Theory

• Fred Hoyle, Hermann Bondi, and Thomas Gold (1948)

• Universe has no beginning or end, although it is expanding, new matter is continuously created so the overall appearance stays the same.

• The universe always looks the same on a large scale (no need for Big Bang)

• CMB strongly contradicts this theory.

• Universe looked different in the past (goes against this theory)

Layers of the earth

1. inner core

2. outer core

3. mantle

4. crust

inner core

• Deepest layer on Earth.

• Made up of iron and nickel but the pressure is so high that it is no longer liquid.

outer core

• List beneath the mantle.

• Contains liquid iron and nickel that spins as the planet rotates and creates a magnetic field (or gravity).

mantle

• 84% of Earth’s volume.

• 2,900 km thick.

• Broken down into 3 main zones.

crust

• Split into 2 types: continental and oceanic.

• 5 to 70 km thick.

terrestrial planets

venus, earth, mars

terrestrial planets similarites

• Made up of solid rocks and silicates.

• All have an atmosphere.

• All have the same time to rotate.

• Earth and Mars have water.

• All have carbon dioxide.

• All have landforms.

terrestrial planets differences

• Venus has no water.

• Venus and Mars don’t have oxygen.

• Venus has sulfur dioxide.

• Mars has carbon dioxide.

• Earth has life forms.

Lithosphere / Geosphere

• Contains all the cold, hard solid land of the planet’s crust (surface),

• the semi-solid land underneath the crust, and

• the liquid land near the center of the planet.

• we are here!!

• planets are also here!!

Hydrosphere

• Contains all the solid, liquid, and gaseous water of the planet. - hence the weather formation + water cycle

• Ranges from 10 to 20 km in thickness.

• Extends downward several km into the lithosphere and upward about 12 km into the atmosphere.

biosphere

• Contains all the planet’s living things. (Microorganisms, plants, and animals)

• Biomes refer to ecological communities based on the physical surroundings of an area.

atmosphere

• Contains all the air in Earth’s system.

• Entends 1m below to more than 10,000 km above the planet’s surface. 

• Upper portion protects the biosphere from the sun's UV radiation.

• Absorbs and emits heat.

• When air temperature in the lower portion changes, weather occurs.

troposphere

• 0 to about 8-15 km above sea level.

• Contains most of Earth’s weather.

• Temperature drops due to decreasing pressure and density of air.

• Warm air rises, leading to convection currents.

stratosphere

• 15-50 km

• Contains the ozone layer, which absorbs and scatters UV solar radiation.

• Temperature increase is due to the absorption of UV radiation by ozone.

• More stable than the troposphere.

mesosphere

• 50-85 km

• Coldest layer of the atmosphere

• Protects Earth from meteoroids, which burn up upon entering this layer.

• Temperature drops (malamig) due to decreasing pressure and less absorption of solar radiation.

thernosphere

• 85-600 km

• Very thin air; temperature increases due to absorption of high-energy solar radiation.

• Home to the Ionosphere - important for radio communication.

• Auroras occur in this layer. - one of the only weather phenomenas in this layer

exosphere

• 600-10,000 km

• Transition between Atmosphere and outer space.

• Composed mostly of hydrogen and helium.

• Very few molecules; particles can travel hundreds of kilometers without colliding.

nitrogen cycle

Describes the movement and transformation of nitrogen in various forms through different parts of the Earth’s ecosystems.

1. nitrogen fixation

Nitrogen gas from the atmosphere is converted into ammonia or ammonium ions by nitrogen-fixing bacteria or cyanobacteria.

2. nitrification

Biological oxidation of ammonia or ammonium ions into nitrite and then into nitrate by nitrifying bacteria such as Nitrosomonas and Nitrobacter.

3. assimilation

Plants and animals take up nitrogen compounds from the soil or water and incorporate them into their biological molecules such as proteins, nucleic acids, and chlorophyll.

4. ammonification

Conversion of organic nitrogen into ammonia and ammonium ions by decomposer bacteria and fungi.

5. dentrification

Specialized bacteria convert nitrate into nitrogen gas, which is released into the atmosphere.

Human Impact on the Nitrogen Cycle:

• Fertilizer Use

• Burning of Fossil Fuels

• Deforestation and Land Use Changes

importance of the nitrogen cycle

• Supports Plant Growth

• Maintains Biodiversity

• Environmental Balance

water cycle

Also known as the hydrological cycle, describes the continuous movement of water on, above, and below the surface of the earth.

1. evaporation

Water from oceans, lakes, rivers, and other water bodies are heated by the sun and changes from liquid to vapor form.

condensation

Water vapor in the atmosphere cools and changes back into liquid form, forming clouds.

precipitation

Water droplets in clouds become heavy enough to fall to Earth’s surface as rain, snow, sleet, or hail.

infiltration

Process where precipitation soaks into the soil and percolates downward through rock layers to replenish groundwater.

surface runoff

• Precipitation exceeds the soil’s infiltration capacity or when the ground is saturated.

• Water flows over the land surface and eventually reaches bodies of water.

transpiration

Release of water vapor from plants’ leaves and stems into the atmosphere.

human influence on the water cycle

• Urbanization

• Pollution

• Climate Change

Importance and Impact of the Water Cycle

• Sustaining Life

• Weather Patterns

• Climate Regulation

• Erosion and Sediment Transport

Mineral

• A (1) naturally occurring, (2) inorganic, (3) solid, (4), that has a definite chemical composition, (5) and a definite crystal structure.

• Examples: Graphite, Sulfur, Talc

A Mineral is Natural

• Must be able to be found in nature; substances conducted in laboratories don’t qualify.

• Cubic zirconia and synthetic corundum are not minerals (do not occur in nature.)

• Not all naturally occurring crystals are minerals (Examples: Opal, Amber, Sap)

• Substances called mineraloids may look like minerals but are not because they don’t satisfy all the requirements for being so.

A Mineral is Inorganic

• Not composed of organic matter; not from living things or the remains of living things.

• These are not minerals for that reason: Coal (plants), Amber (tree sap), Pearls (oysters)

A Mineral is Solid

• Must have a definite volume and shape.

• Stable and solid at room temperature.

• Mercury is not a mineral because it is liquid at room temperature.

A Mineral has a Definite Chemical Composition

Each mineral has its own specific and unique combination of atoms.

• Silicate Minerals

  • Silicon and oxygen groupings; SiO2

  • Combined with one or more metals

  • Largest group of minerals (90% of the earth’s crust)

• Non-Silicate Minerals

  • Do not contain SiO2

  • Subdivided into several other classes.

  • Extremely rare (8% of the Earth’s crust)

  • Few are relatively common (Example: Calcite)

Identifying Minerals:

1. color

2. streak

3. luster

4. hardness

5. cleavage

6. fracture

7. density

1. color

• Not a reliable property; some minerals can be many different colors.

• Colors may vary due to natural coloring agents (impurities) and weathering (exposure to the environment).

2. streak

• The color of the mineral in its powdered form which can be determined using a streak plate.

3. luster

• The way a mineral shines/reflects light from its surface.

4. hardness

• How easily a mineral can be scratched.

• Determined by a mineral’s internal structure.

• When a mineral is scratched by a substance; it is softer than the substance.

• When a mineral scratches a substance; it is harder than the substance.

• Can be tested using the Mohs Hardness Scale.

5. cleavage

• When a mineral splits/breaks along smooth flat surfaces.

• Property of a mineral that allows it to break smoothly along specific internal planes (cleavage planes) when the mineral is struck sharply with a hammer.

6. fracture

• When a mineral breaks unevenly into curved or irregular pieces with a rough and jagged surface.

• Property of a mineral breaking in a more or less random pattern with no smooth planar surfaces.

7. den

• Minerals vary in weight and densities given the same sample size.

uses of minerals

1. ore

2. alloy

3. gems

1. ore

• A mineral that contains metals and nonmetals that can be mined and removed in usable amounts; for a profit.

• Metals - elements that have shiny surfaces, are able to conduct heat and electricity, and are malleable. (Examples: Iron, Aluminum, Copper, Gold)

• Nonmetals - elements that have dull surfaces and are poor conductors of heat and electricity and are brittle. (Examples: Halite, Gypsum, Calcite, Kaolinite)

2. alloy

Mixture of two or more metals or a mixture of metals and nonmetals.

3. gems

• A mineral with desirable qualities; such as hardness, color, luster, clarity, durability, and rarity.

• Precious Stones: Diamonds, Rubies, Sapphires, Emeralds

• Semi-Precious Stones: Amethyst, Garnet, Topaz

• Gems that are not minerals: Pearls, Amber

rocks

• Many kinds of rocks are composed of minerals.

• Monomineralic rocks - composed of only one mineral.

• Polymineralic rocks - composed of two or more minerals.

• There are almost 4,700 different minerals.

sedimentary rocks

• Rocks that usually form in horizontal layers (strata or beds) from the accumulation of sediment, organic matter, or chemical precipitates.

• Composed of rock, mineral, or organic particles.

• Some have a range of particle sizes.

• Some have a uniform sediment size; due to sorting during deposition.

• Some rocks may contain fossils.

igenous rocks

• Forms from the cooling and crystallization/solidification of molten lava or magma.

• Extrusive/Volcanic Igneous Rock - forms from the fast cooling of lava on or near the Earth’s surface. (Small to no crystals; smooth/fine texture)

• Intrusive/Plutonic Igneous Rock - forms from the slow cooling of magma within the Earth. (Large crystals; coarse/rough texture)

Metamorphic Rocks

• Rocks that form from pre-existing rocks that have changed.

• Molecules can rearrange and form new rocks due to contact with extreme heat or pressure.

• Often found in mountainous regions where the deeper bedrock is exposed due to weathering and erosion.

Metamorphism

• Can be caused by: Heat, Pressure, Chemical Activity.

• Contact Metamorphism - rocks around a magma/lava can be metamorphosed through direct contact with the magma/lava.

• Regional Metamorphism - rocks buried deep within the crust can re-crystallize due to extreme pressure during mountain building events.

exogenic processes

Take place at or near the Earth’s surface, that makes the surface wear away.

1. weatheric

• Refers to the physical disintegration or chemical decomposition of rocks and minerals at or near the Earth’s surface.

physical/mechanical weathering

physical breakdown of rocks into smaller fragments without altering their chemical composition.

chemical weathering

alteration of rocks and minerals through chemical reactions with substances such as water, oxygen, acids, and biological agents.

dissolution

When specific minerals are dissolved in water.

hydrolysis

Rock-forming minerals react with water and form different clay minerals.

oxidation

Response of oxygen with minerals.

2. erosion

• Weathered materials are removed and transported from their original location by agents such as water, wind, ice, and gravity. 

• Includes: Water Erosion, Wind Erosion, Glacial Erosion, Gravity Erosion.

3. transportation

• Once weathered materials are detached, they are transported by various agents to new locations.

• Includes: Fluvial Transportation (rivers and streams), Aeolian Transportation (wind), Glacial Transportation (glaciers), Mass Movement Transportation (gravity)

4. deposition

• Transported sediment settles out of the transporting medium and accumulates in new locations. 

• Depositional Environments include: Fluvial Depositional Environments, Coastal Depositional Environments, Glacial Depositional Environments, Aeolian Depositional Environments.

endogenic processes

• Forces and movements that originate from within the Earth, influencing the formation of continents, mountains, earthquakes, and volcanic activity.

• Geological activities that originate within the Earth’s interior.

• Driven by internal heat and energy.

1. plate tectonics

• Describes the movement of large sections of the Earth’s lithosphere (plates).

• Causes phenomena such as subduction zones, mid-ocean ridges, and transform faults.

• May result in the formation of mountain ranges, ocean basins, and volcanic arcs.

2. volcanism

• Molten rock (magma) from the Earth’s mantle reaches the surface through volcanic vents and erupts as lava, ash, and gases.

3. earthquakes

• Sudden movements or vibrations of the Earth’s crust.

• Occur along faults, fractures, or plate boundaries due to the release of accumulated stress.

deformation

• Changes in shape, size, and position of rock bodies in response to stress.

• Diastrophism (Folding & Faulting) and Isostasy

folding

• Bending of rock layers due to compressional forces, typically associated with convergent plate boundaries or mountain-building processes.

faulting

• Rocks break and slide along.

• Normal faults - tensional forces

• Reverse faults - compressional forces

• Strike-slip faults - lateral shearing

stress

• Force that causes pressure in the rocks of the crust.

• Compression - rocks are squeezed together

• Tension - pulls rocks apart

• Shearing - push rocks in opposite directions

geological timescale

• since the beginning of the Earth

• how scientists divided our time on earth

• eons

  • eras

    • periods

      • epochs

Eon

• largest units of geological time

• hundrs of millions to billions of years

Eras

• subdivisons of eons

• tens to hunders of millions of years

• defined by major changes in the Earth’s climate and geography, and the diversity of life

Precambrian Era

• planet was a moletn sphere due to intesne heat

• after a while, the Earth’s surface cooled downallowing life to survive

• lastly, the great oxidation event started

• single celled tiny organisms called prokaryotes → lived in the ocean and didnt have a nucleus → some helped make oxygen

• very warm → high levels of greenhouse gases pero some parts were also very cold → glacial deposits

• formation of Earth’s crust

• first complex cells

Paleozoic era

• age of ancient life

• pangea

• rise of invertebrates, fish, amphibians, reptiles, and first land plants

• named after greek works “palaios” → ancient, and “zoe” → life

• life moved from oceans to land

Mesozoic era

• age of dionosaurs

• dinos were the dominant land animals on Earth

• Middle era

• saw he rise of mammals and birds

cenozoic era

• us rn!!

• age of mammals

• 66 millions years ago to today

• continents have drifted to different positions

• geat diversity among mammals, rise of human civilations