# data[].attributes.headline
4.5 B.Y.A - Start of the Precambrian period

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4.5 B.Y.A - Start of the Precambrian period

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4.5 B.Y.A - The beginning of the solar system 

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4.5 B.Y.A - The beginning of the solar system 

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The solar system formed 4.5 billion years ago from a dense cloud of interstellar gas and dust.

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Also 4.5 billion years ago, Earth formed when gravity pulled swirling gas and dust in to become the third planet from the Sun.

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3.5 B.Y.A - The appearance of invertebrates

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3.5 B.Y.A - The appearance of invertebrates

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Around 3.5 billion years ago, invertebrates appeared in the water and Cambrians, for example, were soft-bodied animals with a carapace or shell.

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2.5 B.Y.A - Start of the proterozoic eon

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2.5 B.Y.A - Start of the proterozoic eon

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2.4-2.2 B.Y.A - The appearance of oxygen in the atmosphere

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2.4-2.2 B.Y.A - The appearance of oxygen in the atmosphere

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Around 2.4-2.2 billion years ago, oxygen appeared in earth's atmosphere from a form of bacteria that could live on energy from the Sun and carbon dioxide.

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1.9 B.Y.A - The appearance of cyanobacteria

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1.9 B.Y.A - The appearance of cyanobacteria

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Cyanobacteria appeared first 1.9 billion years ago by branching off of other bacteria.

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1.56 B.Y.A - The appearance of the first multicellular organisms

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1.56 B.Y.A - The appearance of the first multicellular organisms

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Around 1.56 billion years ago, multicellular organisms appeared from single cell organisms

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Fungi evolved from a common ancestor around 1.2 - 1.5 BYA and not much more is known about the origin of fungi

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800 M.Y.A - The appearance of land animals

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800 M.Y.A - The appearance of land animals

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Once photosynthesis had raised atmospheric oxygen levels high enough, the ozone layer formed, meaning that it was then possible for living things to venture onto the land.

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700 M.Y.A - The appearance of the first plants

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700 M.Y.A - The appearance of the first plants

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Plants are thought to have evolved from an aquatic green alga protist. Later, they evolved important adaptations for land, including vascular tissues, seeds, and flowers. Each of these major adaptations made plants better suited for life on dry land.

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650 M.Y.A - The ice ages and snowball earth

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650 M.Y.A - The ice ages and snowball earth

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The Snowball Earth hypothesis proposes that, during one or more of Earth's icehouse climates, the planet's surface became entirely or nearly entirely frozen.

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Oxygen and O2 react with each other to form ozone which created a thin ozone layer that was capable of protecting life from harmful wavelengths of UV radiation.

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541 M.Y.A - Start of the Paleozoic era & the Cambrian period

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541 M.Y.A - Start of the Paleozoic era & the Cambrian period

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485 M.Y.A - Start of the Ordovician period

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485 M.Y.A - Start of the Ordovician period

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450 M.Y.A - The appearance of the first vertebrates

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450 M.Y.A - The appearance of the first vertebrates

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The earliest known fossil vertebrates were heavily armored fish discovered in rocks and was suggested that ancestors of the sharks and jawed fish were present.

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A global depletion of oxygen caused the planet's first mass extinction about 445 million years ago, an event that killed 80% of the animals in existence at the time.

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444 M.Y.A - Start of the Silurian period

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444 M.Y.A - Start of the Silurian period

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419 M.Y.A - Start of the Devonian period

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419 M.Y.A - Start of the Devonian period

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Insects may have evolved from a group of crustaceans. The first insects were landbound, but about 400 million years ago in the Devonian period one lineage of insects evolved flight, the first animals to do so.

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370 M.Y.A - The appearance of amphibians

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370 M.Y.A - The appearance of amphibians

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The first amphibians evolved from lobe-finned fishes approximately 390 to 360 million years ago. Modern caecilians, salamanders, and frogs all evolved from these basal amphibian ancestors.

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359 M.Y.A - Start of the Mississippian period

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359 M.Y.A - Start of the Mississippian period

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323 M.Y.A - Start of the Pennsylvanian period

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323 M.Y.A - Start of the Pennsylvanian period

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Reptiles first arose from earlier tetrapods in the swamps of the late Carboniferous. Increasing evolutionary pressure and the vast untouched niches of the land powered the evolutionary changes in amphibians to gradually become more and more land-based.

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252 M.Y.A - Start of the Mesozoic era & Triassic period

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252 M.Y.A - Start of the Mesozoic era & Triassic period

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Reptiles first arose from earlier tetrapods in the swamps of the late Carboniferous. Increasing evolutionary pressure and the vast untouched niches of the land powered the evolutionary changes in amphibians to gradually become more and more land-based.

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Morganucodon is usually considered the first mammal but its oldest fossils, only represented by isolated teeth, date from around 205 million years ago.

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201 M.Y.A - Start of the Jurassic period

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201 M.Y.A - Start of the Jurassic period

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145 M.Y.A - Start of the Cretaceous period

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145 M.Y.A - Start of the Cretaceous period

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130 M.Y.A - The appearance of flowering plants

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130 M.Y.A - The appearance of flowering plants

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The ancestors of flowering plants diverged from the common ancestor of all living gymnosperms.

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66 M.Y.A - Start of the Phanerozoic eon, Cenozoic era and the Paleogene period

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66 M.Y.A - Start of the Phanerozoic eon, Cenozoic era and the Paleogene period

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They were flaking crude stone tools by 2.5 million years ago.