Facts about Animal

part 5

61. Gas burnt in your car ends up in plant material

When your car burns gasoline, the fossil fuels are released into the air as carbon dioxide and water vapor. The air pollution stays in the atmosphere for a while, but eventually plants consume it during photosynthesis.

So that same weight from the tank of gasoline gets converted into wood or plant material by photosynthesis.

Given how many cars are being driven daily, plants have access to plenty of “material” for their growth. They just need the ideal conditions to grow.

62. Life evolves on Earth

In flesh and blood, you have been genetically fine-tuned as a product of natural selection. Without evolution, there would be no biodiversity hotspots like tropical rainforests.

This is because life evolved in some of the toughest conditions like an overabundance of water and nutrient-deficient soils. Over time, plants, animals and fungi have developed immunity to harmful bacteria and viruses from these harsh conditions.

This is because whatever doesn’t work just doesn’t survive. Evolution does the work. This is why we find some of the most resistant chemicals for medicine in tropical rainforests.

63. Dinosaurs dominated for 160 million years

Think about it. For 160 million years, dinosaurs dominated the land. Today, we unearth dinosaur fossils of unfathomable size. The theory is that gigantism correlates with oxygen levels in the atmosphere.

Higher oxygen levels meant more size and mass. There is varying opinion on oxygen levels during the age of dinosaurs. Regardless, these reptile-like mammals grew to an extraordinary size.

Ultimately, the demise of dinosaurs was a 6-mile-wide asteroid known as the Cretaceous–Paleogene extinction event. Temperatures began to plummet because a dust cloud blocked the sun.

64. Mass extinctions are common in nature

Earth has experienced 5 mass extinctions. More than 99% of species that existed are now extinct. Time and time again, the reign of a species has fallen with an abrupt ending.

For example, ocean/atmosphere chemistry, climate change, volcanic activity, and meteor/asteroid impacts had fatal consequences. No matter how far back you look, nature has found its way to reshuffle the deck.

Large mammals are at greater risk. For example, giant sloths, mastodons and saber-toothed tigers became extinct only about 10,000 years ago. They just couldn’t find a way to outmuscle nature.

65. The supercontinent cycle

The land beneath our feet is in motion. We know this is true because we measure their movements using global positioning satellites.

On average, continents move about 1 inch per year. Plate tectonics drive the reshaping of continents. Inch by inch, this accounts for incredibly long distances over millions of years.

Long ago, cratons merged to create vast stretches of land. For example, Vaalbara, Ur and most recently Pangaea (sometimes spelled Pangea) took part in the supercontinent cycle.

66. Supercontinents and superoceans

One continent. One ocean. If you had a time capsule and traveled back in time 200 million years ago, you’d experience Earth as one of the supercontinent of Pangaea.

From coast to coast, Pangaea was surrounded by the superocean Panthalassa. Gradually, continental drift tore the supercontinent apart into our current placement of continents.

Today, we pick up the pieces and look at the clues of Pangaea. For example, notice the striking similarities of continental boundaries aligning in a world map.

67. Dinosaur fossils from Pangea

Dinosaurs lived on the supercontinent of Pangea for over 160 million years. Plate tectonics was the mechanism that eventually tore continents apart.

We know this because we can find the same fossils on separate continents today. We see fossils of the same land herbivores today on separate continents that couldn’t fly or swim.

The reason is that they lived on Pangaea and over time it separated. To this day, scientists have kept a thorough record documenting each fossil discovery.

68. The geologic time scale

The geologic time scale of Earth is almost unimaginable to us. This is because human lifespans are so short in comparison.

We work in hours, days, months, and years. But the Earth works in decades, centuries, and millions of years.

Like chapters in a book, geologists partition Earth’s history into periods, eras and epochs. Each block of geologic time has a notable start and end. So that means that timing is everything when it comes to the geologic time scale.

69. Meteorites date the Earth as 4.5B years old

Geologic time seems to be a Goliath that many of us David earth scientists wrestle with. Earth is a staggering 4.5 billion years old.

Despite the challenges of grappling with geologic time, we can come up with a decent estimate of Earth’s age by studying meteorites.

Meteorites are remnants from when all the planets were forming. Some of them still land on the planet today. By dating meteorites, we find that the oldest rocks are often 4.5 billion or so years old.

70. Carbon dating uncovers age

All life contains different types of carbon. When an organism dies, carbon-14 (C14) breaks down. However, carbon-12 (C12) doesn’t break down.

By examining the ratio between the two for dead matter, we can estimate age with carbon dating. But there are limitations to measuring beta decay.

At a certain age (60,000 years or so in history), there isn’t enough carbon-14 that remains from the organism to make an accurate estimate.

71. The Grand Canyon reveals Earth’s age

Rocks tell us about colliding continents, meandering streams and volcanic eruptions. In the case of the Grand Canyon, the multi-layered strata provide insight to the age of the Earth.

Like a stack of pancakes, younger rock layers pile on top of older layers. We use the law of superposition to reveal Earth’s age. For example, the base of the Grand Canyon is Precambrian basement rocks.

These were formed from flowing magma which cooled and hardened about 1.8 billion years ago. Most of the rocks on top are sedimentary like shale, limestone and sandstone.

72. Magnetic pole reversals

The Earth is one big magnet. This is why when you use a compass, it points to the magnetic north. But north didn’t always point northward.

On average, it takes 250,000 years for Earth’s magnetic north to flip polarity. As shown in rocks, magnetic pole reversals are one of the key gateways to recognizing the past.

On average, pole reversals occur every 200,000 to 300,000 years. We may be due for one soon.

73. Planetary (Chandler) Wobbles

Earth spins on its axis of rotation. But it doesn’t spin perfectly. Like a toy top, it wobbles when it spins. This displacement is known as the Chandler wobble.

Precession occurs because the Earth is not a perfect sphere. It flattens out at the poles. But the Chandler Wobble actives a wobble that is minuscule.

It’s just 20 feet in deviation at the North Pole. No longer a mystery, the key driver of wobbling is temperature and salinity changes at the bottom of the ocean.

74. Ice ages are periodic

Earth revolves around the sun in a roughly circular orbit. But roughly every 200,000 years, its orbit becomes more eccentric from gravitational interactions.

It’s close to circular now. But like a pendulum, the eccentricity will swing back the other way. It’s because Venus is so close and Jupiter is so large that gravity affects its orbit.

There’s been a noticeable trend in climate, temperature and seasons due to the Milankovitch cycle.

75. Earth was a snowball

Earth experienced 5 large ice ages. During this time, a hefty layer of ice smothered our planet. It was unimaginably frigid at this time where temperatures dropped to 10°C lower than it is today.

Ice ages happen for several reasons. In the eyes of Milankovitch, Earth is prone to ice ages because of how its cyclical movements affect climate.

At least, this is reasonable to assume for the last ice age 10,000 years ago. Atmospheric chemistry, solar output and ocean currents can trigger ice ages.

76. Glaciers chisel away the land like a rake

Like a rake scraping the dirt, glaciers leave a lasting impression on the land. During the last ice age, glaciers scraped away rock in Canada dumping most of it the northern United States.

They tore mountains down carrying a vast amount of rocks from the continent across the border. Continental glaciers chisel away at the land leaving its fingerprint in the land.

For example, Long Island, New York is the result of glacial debris from the sediment dumping of a glacier terminal moraine.

77. Continents are still rebounding from the last ice age

Only about 10,000 years ago, ice covered all of Canada. Mountains made of ice pushed down on the continent with immense pressure. For example, the Hudson Bay may have depressed over one kilometer.

After the ice melted, Canada began lifting. We know this because we measure its vertical motion with GPS. Imagine squeezing a sponge and watching it return to its shape.

Similarly, isostatic rebound is quick at first, then slows down. This process of glacier rebound is due to the asthenosphere behaving in a fluid manner. Because ice had been removed, the compressional force no longer exists.

78. Humans have only explored 20% of oceans

We’ve mapped 100% of our oceans at 5 km resolution using satellite radar. If you account for shipping routes and scientific expeditions, we’ve mapped out about 20% of ocean bathymetry with sonar.

So that means we have oceans mapped at about 100 meters resolution which is the same as our surface maps of Venus and Mars. The other 80%? The reality is that most of our oceans are totally untouched. Even though 70% of Earth is covered by oceans, we know little about our ocean seafloor.

Despite the need to understand ocean CO2 sequestration, nutrient recycling, and untapped energy resources, the biggest drawback is the high cost of exploring oceans.

79. The Earth is breathing

The Earth is breathing. We gauge Earth’s metabolism based on the rate at which plants absorb carbon dioxide out of the atmosphere.

Net primary productivity is how much carbon dioxide is taken in during photosynthesis minus how much is given off during respiration.

For example, lush tropical rainforests are the most productive places on the planet. But tundras are the least productive because little photosynthesis takes place in polar regions.

80. Climate feedback loops

Climate feedback loops either amplify or reduce climate change. For example, a warmer climate could increase cloudiness because of the increased water vapor in the atmosphere.

Because clouds reflect ⅓ of incoming solar radiation, more clouds could slow the increased warming from less heat absorption. This is an example of a negative feedback loop.

An example of a positive feedback loop is the melting of permafrost. This amplifies climate change because its methane contents would be released into the atmosphere.