Earth Science Quiz 1

four linked concepts that we will discuss repeatedly over the course of the semester

1. Human Population Growth

2. Sustainability

3. Linked Earth Systems

4. Environment and Resource Inequities

because humans are at the intersection of these 4

population growth

important because supply and demand! Our need for stuff drives the need for resources which has an impact on the environment

For example, countries in Africa get their resources taken to make things they don’t have like electric cars

Exponential population growth

All of a sudden, we have massive growth ever since the Industrial Revolution

So can this planet sustain the population growth? Probably yes, but not everywhere

America is not sustainable

We have to import about 45 precious metals

Venezuela has the 2nd largest oil reserves in the world. We should be dependent on them, but we’re not

growth rate

in 1920s, started growing rapidly. better healthcare.

in 2100, its predicted to dip a tiny bit then stabilize around 10.43 billion

Nigeria is predicted to take our spot as 3rd largest population

Chinese famines

dip in population during this time. also dipped during covid.

in 2080 projected deaths and projected births predicted to crossover

world population growth rate

biggest in africa, then asia, then south america, then north america

population density worldwide

china, india, europe have high population densities. Africa and americas are after that. Do they have enough resources to sustainably support the population?

birth rate worldwide

Africa is the highest, everyone else is pretty normal

Fertility rate vs GDP per capita

inverse relationship

poorer countries like African countries make less money but produce more children and vice versa

Five Stages of Demographic Transition

Stage 1: stable or slowly increasing

Stage 2: Rapidly increasing

Stage 3: increase slows down

Stage 4: falling and then stable

Stage 5: little change

Stage 1 is the most problematic (poorer countries) and stage 5 is more stable, like America

Differences in fertility rate

= for men and women for all age groups in Haiti, USA, and Nigeria

Culture in Haiti

Economics in USA

Education in Nigeria

These factors drive a change in population structure

One child policy

Didn’t have enough people in the workforce so rescinded the law

Why is population growth a problem?

1. Pollution of the environment (e.g., surface water, atmosphere)

2. Production and management of hazardous waste

3. Exposure of populations to natural hazards; disease

4. Over-exploitation of natural and non-renewable resource

Sustainability

Development which ensures that future generations will have equal access to the resources our planet offers

Types of development that are economically viable, do not harm the environment, and are socially just

Sustainability Impacted by Land Use

The Aral Sea btwn Uzbekistan and Kazakhstan – once a tourist destination, the region has been greatly damaged by human activity

Lake used to be 4th largest lake in the world. Now it’s split into a north and south section

Used to be used for tourism and fishing

Collapse of Atlantic cod stocks

Peaked in 1960s then started declining and almost completely collapsed in 1992 because even though cod was fished sustainably Ecosystem has been changed – Cod was a top-tier predator and fed upon smaller prey such as herring and shrimp

Cod populations may never recover: In 2007, offshore cod stocks were 1% of what they were in 1977

Feed back loop

Do something and an unintended consequence happens

4 linked Earth systems

atmosphere, hydrosphere, geosphere, biosphere

system

any complex whole, with smaller connected parts working together. Usually, a change or malfunction of one part can affect other parts of the system and also affect the system itself (“feedbacks”)

Earth system

Earth´s interacting physical, chemical, and biological processes. The system consists of the geosphere (land), hydrosphere (oceans; groundwater), atmosphere and biosphere (floral; fauna).

It includes the planet's natural cycles — the carbon, water, nitrogen, phosphorus, sulfur and other cycles — and deep Earth processes

CO2

The oscillations have to do with photosynthesis

Climate change is huge

These observations of rising temps are worldwide

Coral

• Sustain productive fisheries

• Tourism

• Protect shorelines from erosion

CO2 in the oceans

Oceans have absorbed nearly one half (~ 525 billion tons) of human-related CO2 since the industrial revolution

Ocean pH has decreased over time as Atm. CO2 has increased and many marine organisms are not adapted to these more acidic conditions. this is bad!

effects of this increasing ocean acidity on corals

• Reefs may be dissolved faster than they can be rebuilt

• Foraminifera shells weights are 30-35% lower than shells of their counterparts from thousands of years ago

Physical/Social differences between Haiti & Dominican Republic

• Dominican Republic has greater area suitable for agriculture

• Eastern side of island receives more rainfall than western side

• Haiti has more rugged topography and steeper slopes

• Forest cover ∼7 times greater for DR versus Haiti

• Haiti population growth 1.8 times greater than DR

This is why DR is more green than Haiti

Deforestation is one major problem facing Haiti

Massive deforestation over the last 100 years – how much?

After Haiti won its independence from France in 1804, a treaty was signed by which France would recognize Haiti’s independence in exchange for 150 (later reduced to 90) million gold Francs. Haiti’s trees were felled and exported to France to service the debt.

Deforestation has led to: 1. Reduced soils quality – an estimated 15,000 acres of topsoil washed away each year

2. Less agricultural production – eventually leads to desertification

3. Increased risk of landslides

4. Increased movement of population to urban areas

Slums in Port au Prince, Haiti – an inequity issue?

barely any fresh water

key concepts contributed to the disaster in Haiti

• Lack of sustainability – deforestation caused a multitude of problems (poor economy, migration to city)

• Population growth led to disadvantaged people living in slums in the overpopulates capital city

• Hazardous earth processes – Port au Prince is located on a major fault line

bad history of Haiti

Haiti was a slave country owned by the French

In 1789, Haiti was the most productive French colony; however, a bloody slave revolution in 1791 resulted in a free Haitian republic

Unfortunately, the bloody nature of the revolution meant that European traders were mistrusted; trade was therefore limited.

In addition, a unique language and dialect was spoken in Haiti, leading to communication problems with the rest of the world

Haiti Earthquake

January of 2010

Magnitude 7.0

Haiti sits directly on a plate tectonic boundary

• Earthquake hit a large urban area

• Poorly constructed houses

• Federal government rescue limited (limited resources)

Rock

naturally occurring solid aggregate of one or more minerals or mineraloids (non-crystalline, amorphous)

ex. salt

Mineral

naturally occurring substance that is solid and inorganic representable by a chemical formula, usually abiogenic, and has an ordered atomic structure

Igneous rock

formed through the cooling and solidification of magma or lava. May form with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic-lava) rocks

Sedimentary rock

Weathered rocks

rocks that are formed by the deposition of material at the Earth's surface and within bodies of water (e.g., oceans, lakes, rivers)

Metamorphic rock

igneous or sedimentary rocks subjected to heat (>400 o F) and pressure (>20,000 atm) causing profound physical and/or chemical change

Understanding the age and evolution of Earth is important for a range of scientific questions

• Evolution – inorganic, biologic (e.g., humankind)

• Climate change and potential impacts (that is - lessons we learn from the past)

• Geologic processes (e.g., hazards, rates)

• Distribution of valuable energy and mineral resources

Archbishop James Ussher of the Church of Ireland

Tried dating Earth making a careful study of the Bible and other historical sources - October 23, 4004 B.C

Edmund Halley

Tried dating Earth by suggesting dividing the total amount of salt in the world’s seas by the amount added each year (80-90 million yrs ala John Joly in the 1890s)

Georges-Louis Lecler

Tried dating Earth by heating spheres until they glowed white hot and then estimating the rate of heat loss by touching them; scaled to the size of Earth - 75,000 and 168,000 years old

Charles Darwin

In 1859 in ‘On the Origin of Species’, Charles Darwin tried to date the Earth by announcing that the geological processes that created an area of southern England, had taken 306,662,400 years to complete

Dating the Earth by the end of the 19th century

• Depending on which text you consulted, the number of years that stood between us and the dawn of complex life was 3 million, 18 million, 600 million, 794 million, or 2.4 billion—or some other number within that range

• Even as late as 1910, one of the most respected estimates, by the geologist George Becker, put the Earth’s age at perhaps as little as 55 million years

Huge range!

Marie Curie

• In 1896 in Paris, Henri Becquerel carelessly left a packet of uranium salts on a wrapped photographic plate in a drawer.

• When he took the plate out some time later, he was surprised to discover that the salts had burned an impression in it, just as if the plate had been exposed to light. The salts were emitting “rays” of some sort.

• He turned this project over to a graduate student, Marie Curie

• She found that certain kinds of rocks released a constant amounts of energy, yet without diminishing in size or changing in any detectable way

• What she couldn’t know was that the rocks were converting mass into energy in an exceedingly efficient way. She dubbed the effect “radioactivity”

Marie Curie and Ernest Rutherford

• At McGill University in Montreal, Ernest Rutherford had taken an interest in the new radioactive materials

• He discovered that immense reserves of energy were bound up in these small amounts of matter, and that the radioactive decay of these reserves could account for most of the Earth’s warmth

half life

Radioactive elements decayed into other elements—that one day you had an atom of uranium, say, and the next you had an atom of lead – this decay happens at a constant, steady rate

atoms

TINY building blocks of matter

Can be very long lived (it is thought ∼1035 years) –every atom that makes up you has almost certainly passed through several stars, and been part of millions of organisms before it became part of you

Atomic Structure

• Every atom is made from three kinds of elementary particles: protons, which have a positive electrical charge; electrons which have a negative electrical charge; and neutrons, which have no charge

• Protons and neutrons are packed into the nucleus, while electrons spin around outside (well, not exactly)

• The number of protons is what gives an atom its chemical identity (atomic number).

C-12

common stable isotope of carbon

Living things are composed mostly of C-12

uranium

Elements with atomic number >83 are radioisotopes; nucleus is unstable

The half-life of uranium-238 is about 4.47 billion years and that of uranium-235 is 704 million years, making them useful in dating the age of the Earth

ionizing radiation

The nucleus of an unstable atom loses energy by emitting this. can include alpha, beta, and gamma rays

Alpha decay

occurs via the emission of a helium nucleus

Beta decay

occurs via the emission of either an electron or positron

radiometric dating

• The steady decay (half-life) could be used as a ‘clock’ to test the age of material (Rutherford, 1905)

• One of the first materials tested was a piece of pitchblende, or uranium oxide. Rutherford found it to be 700 million years old—very much older than the age most people were prepared to grant the Earth

It would be decades before we got within a billion years or so of Earth’s actual age

Uranium and Lead isotopes

• In 1948, Dr. Clair Patterson at the Univ. of Chicago used a technique of counting uranium/lead ratios in old rocks; chiefly examining the decay of U-238 to Pb-206

• However , what rocks to use? Why is there a problem finding old rocks on Earth?

• Dr. Patterson assumed that many meteorites are essentially leftover building materials from the early days of our solar system and may have managed to preserve a pristine interior chemistry. Measure the age of these wandering rocks and you might have the age also of the Earth (near enough).

• His measurements placed the age of the Earth at 4,550 million years (plus or minus 70 million years)

moon

formed from pieces of the Earth

The moon has not undergone plate tectonics and has no atmosphere, provides quite precise age dates from the samples returned from the Apollo missions. Moon rocks have been dated at a max of around 4.4 and 4.5 billion years old

oldest minerals

small crystals of zircon (ZrSiO4) from the Jack Hills of Western Australia – are at least 4.404 billion years old

Earth Systems as time

Once we had determined how to date geological samples accurately we could then start assessing the evolution of Earth’s geosphere, hydrosphere, atmosphere and biosphere across this wide expanse of time – 4.5 to 4.6 billion years

Geological Time Circle

Early earth was very primitive, no oceans only lava lakes

Eventually we see single cell and multi cell creatures

Moon formed early on

Complex earth like humans and dinosaurs are really recent

Sculpting of the Earth

Very early earth didn’t have core or crust or tectonic plates. Lots of CO2, not that much oxygen

Water came

The core is iron and nickel because they are dense so they sunk deep into the Earth

Earth started to separate into zones based on types of elements

Geomagnetic fields around Earth provide us protection from the sun and allows life to emerge

Formation of the Earth

• About 4.6 billion years ago, gas and dust some 15 billion miles across accumulated in space where we are now and began to aggregate.

• Virtually all of it—99.9 percent of the mass of the solar system—went to make the Sun.

• Out of the remaining material, two microscopic grains floated close enough together to be joined by electrostatic forces. This was the moment of conception for our planet.

• Colliding dust grains formed larger and larger clumps. Eventually the clumps grew large enough to be called planetesimals.

• To grow from a tiny cluster of grains to a baby planet some hundreds of miles across is thought to have taken only a few tens of thousands of years. In just 200 million years, possibly less, the Earth was essentially formed.

• Early sun was 10% dimmer early on

Earth Cooling and Primitive Life

First oceans

DNA

Tectonic Activity

First continent

Prokaryote bacteria

Banded Iron formation

Great Oxygenation event

How did life form

There are many theories to this question. An experiment in 1953 by Stanley Miller and Harold Urey showed that life’s “organic building blocks” could form in an atmosphere of water, methane, ammonia and hydrogen with the aid of sparks to mimic the effect of lightning

New concept: life started in a deep ocean with white bacteria

Earth: An Oxygenated Atmosphere

Oxygen crisis

First Eukaryotes

Snowball Earth

Multicellular life

Ozone stabilization

The Cambrian Explosion and Fossil Records

Cambrian explosion

Age of invertebrates

Age of fish

Fungi

Land plants

Age of amphibians

Insects

Coal deposits

Extinction

The Age of Reptiles and Dinosaurs

Age of reptiles

Pangea

Age of conifers

Age of dinosaurs

Birds

Small mammals

Flowering plants

The Age of Mammals and Homo Sapiens

Dinosaur extinction

Age of mammals

Primates

Grass

Modern Earth

Apes

Stone age

Homo sapiens

Cities

Earth History was represented in a 24-hr Timeline

00:00

04:00 Life begins

20:30 Sea plants appear

21:00 Jellyfish

21:04 Trilobites and other organisms (Cambrian explosion)

21:55 Plants colonize land

22:00 Animals colonize land

22:24 Earth covered by great forests --> coal, insects appear

22:55 Dinosaurs arrive

23:38 Dinosaurs extinct

23:40 Age of mammals

23:58:43 Humans appear