The theory of continental drift was proposed by someone.
In the past, it was thought that the Earth's crust was immobile, that the continents had always been in their present positions, and that the ocean floors were only a catch basin for debris that washed off the land.
Alfred Wegener presented data from a number of disciplines to support his hypothesis of continental drift.
The continents formed a supercontinent called Pangaea during the Paleozoic era.
The continents of today were formed when Pangaea split into two large subcontinents, called Gondwana and Laurasia.
The continents are drifting in relation to one another.
The continents joined into a supercontinent called Pangaea.
Laurasia and Gondwana were formed when the continents of Pangaea began moving apart.
The continents began to separate.
Europe and North America are drifting apart at a rate of 2 cm per year.
For example, the west coast of Africa is similar to the east coast of South America.
Many of the areas where the continents touched have the same geological structures.
A single mountain range runs through South America, Antarctica, and Australia.
The unique distribution patterns of fossils are explained by Continental drift.
Australia, South America, and Africa share a common ancestry with mammals that were widely distributed across Gondwana.
Each continent has its own representatives of the rodents.
After the continents separated, each continent has its own unique mammal lines.
Today's world is the result of isolated evolution on different continents.
According to the fossil record, marsupials were abundant in South America until about 7 mya.
In the Australian biogeographical region, Marsupials are more common than in South America.
It is most likely due to the evolution of marsupials in the Americas and Australia.
marsupials were able to grow without competition from the mammals that evolved elsewhere.
Bats and rodents are the only mammals native to Australia.
The rest of the mammals were introduced recently.
In the Americas, placental mammals are common, and much of the marsupial diversity has disappeared.
The answer to why continents drift has been suggested through plate tectonics. "
molten, able to flow" The idea shows that the Earth's crust is fragmented into plates that float on a hot mantle layer.
The continents and the ocean basins are part of rigid plates that move like conveyor belts.
As mantle molten rock rises and material is added to the ocean floor, seafloor spreading occurs.
On average, the continents move a few centimeters a year due to seafloor spreading.
The amount of oceanic crust being formed is the same as the amount of destruction.
When two continents collide, the result is often a mountain range.
The movement of the two plates is responsible for the many earthquakes in southern California.
The movement of plates at transform boundaries is visible from earthquakes.
In rare cases, the movement of the plates has been witnessed by people as they occur--roads diverging, the ground shifting, and cracks emerging.
There have been at least five mass extinctions throughout history.
Mass extinction can be caused by catastrophic events or a gradual process of environmental change.
The thickness of the bars shows the amount of life-form considered.
The idea that the extinction of the dinosaurs was due to a bolide was proposed by Walter and Luis in 1977.
A is a projectile that impacts the Earth.
iridium is rare in the Earth's crust but more common in asteroids and meteorites than in clay.
The impact of the comet was108 megaton.
Page 334 contains ash and soot that would block the sun.
A crater that could have been caused by a meteorite impact was found in the Caribbean-Gulf of Mexico region.
The impact to the end of the Cretaceous and beginning of the Tertiary periods was dated by a layer of soot.
The crater is called the Chicxulub crater.
It's possible that continental drift contributed to the extinction.
Gondwana arrived at the South Pole.
Immense glaciers drew water from the oceans.
The marine invertebrates and coral reefs, which were especially hard hit, didn't recover until Gondwana moved away from the pole.
The end of the Devonian period saw the mass extinction of 70% of marine invertebrates.
Survey notes that iridium has been found in rocks in Australia, suggesting that a bolide event was involved.
The mass extinction could have been caused by the movement of Gondwana back to the South Pole.
Most of the species disappeared at the end of the Permian period.
Excess carbon dioxide is attributed to the extinction.
Pangaea did not have polar ice caps to initiate ocean currents.
The organic matter at the bottom of the ocean was stagnant because of the lack of ocean currents.
The ocean circulation went back on as the continents changed.
Carbon dioxide is a deadly gas for sea life when it is swept up to the surface.
The crinoids barely survived the extinction of the trilobites.
Climate change was caused by excess carbon dioxide on land.
The areas that were wet and rainy became warm and dry.
Animals that can escape land surface changes have the best chance of survival.
The extinction at the end of the Triassic period was caused by the environmental effects of a meteorite collision.
Some believe that the impact site of Central Quebec is half the size of Connecticut.
The first of the giant dinosaurs took charge of the land during this event.
The second wave ended in dinosaur extinction, as was previously discussed.
Evidence from the biogeographical distribution of organisms supports the theory of continental drift.
The origin of self-replicating molecules was the beginning of biological evolution.
The multicellular animals did not evolve until 630 mya.
The Paleozoic era started with a rich animal fossil record.
The evolution of a hard external enclosure may have been influenced by predation pressures.
The fishes were the first to become dominant.
Amphibians are descended from fishes.
The land was invaded by plants.
There were seedless plants in the swamp forests of the Carboniferous period.
The Age of Amphibians is sometimes called this period.
The Age of Cycads and Reptiles was during the Mesozoic era.
Birds and mammals are descendants of reptilian ancestors.
Dinosaurs of enormous size were present.
The dinosaurs were extinct by the end of the period.
The Cenozoic era is divided into two periods.
The adaptive radiation of mammals and flowering plants is associated with the tertiary.
The pressure on primates to live in trees was put on by the replacement of forests with grassland.
primates who left the trees may have been the result of the evolution of humans.
The land is carried on huge plates that move.
The history of life on Earth has been affected by five mass extinctions.
Evidence shows that other extinctions have the same cause.
Due to continental drift, it has been suggested that there can be mass extinctions.
Pick the best answer for the question.
Match the statements with the events in the key.
Answers can be used more than once.
The heat of the sun could have caused the formation ofProteinoids.
In a liquid environment, the molecule that forms a membranes is called a phospholipid.
The oceans were formed as the Earth cooled.
Miller's experiment shows that under certain conditions, organic chemicals can form small organic molecules.
There may have been an abiotic synthesis.
The evolution of the genes was a milestone.
Fossils are the remains of past life.
Match the phrases with the divisions of geologic time in the key.
Answers can be used more than once.
Mass extinctions are explained by continental drift.
Figure 18.9 is the evolutionary tree of life you were asked to supply.
Discuss how excess carbon dioxide led to extinction.
Take a few moments to review the discussions before you start this chapter.
A T4 cell with HIV is used in a criminal case.
Problems in agriculture, medicine, and forensic science have been addressed thanks to the ability to identify the genetic profile of an organisms.
A gastroenterologist was found guilty of attempted murder of his girlfriend when he injected her with HIV and hid it in a B12 shot.
One of the doctor's patients with HIV/AIDS was traced to the girlfriend's HIV.
The doctor's victim's HIV lineages are nested within the doctor's patient's in the image above.
The doctor was sentenced to 50 years in prison for attempted murder because of this evidence.