History of Earth and Evolution Review

Evolution by natural selection requires variation in a population. This variation is primarily introduced through random mutations in the DNA.

Embryology, DNA, and fossils are all direct evidence for evolutionary relationships and history. Radiometric dating is a tool used to date rocks and fossils, but it is not itself evidence of biological evolution.

The most recent glacial period, often referred to as the last ice age, ended approximately 11,700 to 11,800 years ago.

The Cretaceous-Paleogene extinction event, which wiped out the non-avian dinosaurs, resulted in the loss of approximately 70-75% of all species on Earth.

The current scientific consensus suggests a chain reaction: a massive meteor impact triggered widespread volcanic activity, which released enough dust and gas to block sunlight, causing a collapse of the food chain.

Non-avian dinosaurs went extinct approximately 65.5 to 66 million years ago at the end of the Cretaceous period.

The Mesozoic Era (252 to 66 million years ago) is famously known as the Age of Reptiles, during which dinosaurs were the dominant terrestrial vertebrates.

The Permian-Triassic extinction event, which ended the Paleozoic era, is widely attributed to massive volcanic eruptions (the Siberian Traps) that caused extreme climate change.

The Permian-Triassic extinction event was the most severe in Earth's history, resulting in the extinction of approximately 95% of marine species and 70% of terrestrial vertebrate species.

The Permian-Triassic extinction, occurring at the end of the Paleozoic era, is considered the largest mass extinction in Earth's history.

Early Earth was extremely hot due to volcanic activity and the lack of an atmosphere that could retain heat in a way conducive to current life. Estimates for the early environment suggest very high temperatures.

Early Earth is thought to have been covered by a global ocean, with very little land mass exposed compared to today.

The earliest evidence of life on Earth dates back approximately 3.5 to 3.8 billion years ago.

Evidence for the earliest life forms, such as stromatolites, dates back to approximately 3.8 billion years ago.

The Earth is estimated to have formed approximately 4.5 to 4.6 billion years ago.

The Cenozoic Era is often called the Age of Mammals because mammals became the dominant land animals following the extinction of the dinosaurs.

The Mesozoic Era is known as the Age of Reptiles, during which dinosaurs were the dominant terrestrial vertebrates. The Paleozoic preceded it, and the Cenozoic followed it.

The Paleozoic Era began with the Cambrian Explosion, a period characterized by a rapid diversification of life forms. The PreCambrian came before this event.

The PreCambrian accounts for the vast majority of Earth's history, spanning from the formation of the planet until the beginning of the Paleozoic Era.

Index fossils are fossils of organisms that lived for a short, well-defined period and were geographically widespread, making them useful for dating rock layers.

Radiometric dating measures the decay of radioactive isotopes, such as carbon-14 or uranium, to determine the absolute age of rocks or fossils.

The half-life is the specific amount of time required for half of the radioactive atoms in a sample to decay into a stable daughter isotope.

Natural selection is the mechanism where individuals with advantageous traits are more likely to survive and pass those traits to the next generation.

A species is defined as a group of organisms that can interbreed and produce fertile offspring in nature.

Fossils are the preserved remains, impressions, or traces of organisms that lived in the past.

Relative dating determines the age of a fossil by its position in rock strata, where lower layers are generally older than upper layers.

Homologous structures are body parts that share a common evolutionary origin, even if they serve different functions in different species.

Evolution is the process of change in the inherited characteristics of a population over successive generations.

Hominids are the group consisting of modern humans, extinct human species, and all our immediate ancestors.

Extinction occurs when the last individual of a species dies, resulting in the permanent loss of that species.

Embryology is the branch of biology that studies the development of organisms from fertilization to birth or hatching.

Primates are a group of mammals characterized by large brains, forward-facing eyes, and grasping hands, including monkeys, apes, and humans.

An endangered species is one that is at high risk of becoming extinct due to low population numbers or loss of habitat.