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Period: 1 CE to 1 CE
Quaternary Period
As the climate cooled, large forests died off, leaving open grasslands. Grasses flourished due to their ability to adapt to dry, arid conditions. Humans began to cultivate plants as a food source. Starting about 13,000 years ago, the earliest agriculture consisted of cultivating grass-type plants. These were grains such as wheat and barley. Later, ancient humans learned to cultivate corn, squash, beans, and new grains such as millet and rice. -
Period: 66 to 1 CE
Tertiary Period
Grasses evolved during this period leading to the development of vast savanna ecosystems. The proliferation of grasses provided food for large, grazing mammals and protection for small animals such as rodents. Conifers dominated in colder climates, while angiosperms (flowering and fruiting plants) dominated in tropical climates. -
Period: 145 to 66
Cretaceous Period
plants in which male or female reproductive organs are housed in a flower, proliferated and became the dominant plants. Modern-day trees appeared. Conifers continued to be important trees in colder regions. Ancestors of modern-day ferns evolved -
Period: 201 to 145
Jurassic Period
The climate became wetter, leading to development of large jungles where conifers dominated the landscape. Flowering plants appeared during this period, but they played only a minor role among other plants. -
Period: 251 to 201
Triassic Period
Seed-bearing plants dominated over all others. Gymnosperms, such as cycads, ginkgos, and conifers, were the most prevalent plants of this period. -
Period: 299 to 251
Permian Period
The climate dried, leading to the advanced conifers. Widespread forestation appeared in some regions. -
Period: 358 to 298
Carboniferous Period
Seed plants developed and colonized habitats where spore producing plants could not flourish. -
Period: 419 to 358
Devonian Period
Plants developed sexual organs for reproduction, stems with vascular tissue, and woody tissue for structure. There came to be new ecosystems with more varieties of plants. -
Period: 443 to 419
Silurian Period
The adaptation of vascular systems enabled land plants to stand upright and draw water upward through their structures. -
Period: 485 to 443
Ordovician Period
Most plants were in wet environments because most were non vascular. These plants reproduced by spores. -
Period: 541 to 485
Cambrian Period
Terrestrial plants started cooling the atmosphere because of such high volcanic matter.