Plant Evolution

Algae living in the oceans

1 CE

700 million years ago

Pre-Cambrian Era (4000-542 Million Years Ago)

2

Plants first appeared on land approximately 700 million years ago. The increased oxygen in the atmosphere helped facilitate new life and evolution.

Cambrian Period (541-485 Million Years Ago)

3

Most plant life cosisted of small, soft, marine plants, such as green algae. When terrestrial plants evolved, they cooled the climate and provided oxygen for new life to begin on land.

Ordovician Period (485-443) Million Years Ago

4

Because the earliest plants were non-vascular, they did not conduct water. Terrestrial plants primarily lived in wet enviroments. These plants reproduced by spores.

Silurian Period (443-419 Million Years Ago)

5

The first vascular plants evolved. Most Silurian plants showed no differentiation of leaves, stem, and roots. Allowed plants to draw water through their structures.

Devonian Period (419-358 Million Years Ago)

6

The first recognizable soils developed. Plants developed sexual organs for reproduction, stems with vascular tissue, woody tissue for structure, and stomates for respiration.

Carboniferous Period (358-298 Million Years Ago)

7

Seed plants developed and colonized habitats where spore-producing plants couldn't flourish.

Permian Period (299-251 Million Years Ago)

8

The climate dried, which led to the evolution of advanced conifers. Cycads and ginkgos became present. There was widespread forestation in some regions.

Triassic Period (251-201 Million Years Ago)

9

Sead-bearing plants dominated. Gymnosperms where the most prevalent plant.

Jurassic Period (201.3-145 Million Years Ago)

10

The climate became wetter, which developed large jungles. Conifers dominated the landscape. Flowering plants played a minor role in this period.

Cretaceous Period (145-66 Million Years Ago)

11

Angiosperms developed and became the dominant plants. Modern-day trees appeared. Conifers continued to be pertinant trees in cold regions. Ancestors of modern-day ferms evolved during this period.

Tertiary Period (66-1.8 Million Years Ago)

12

Grasses evolved to develop the savanna ecosystem. This provided food for large grazing mammals and protection for small animals. Conifers dominated cold climates and angiosperms dominated tropical climates.

Quaternary Period (1.8 Million Years Ago-Present Day)

13

As the climate cooled, large forests died off. Grasslands thrived because of their adaptability to dry conditions.

Quaternary Period (13,000 Years Ago)

14

The earliest agriculture consisted of cultivating grass-type plants (wheat, grain, barley. Later, humans learned to cultivate corn, squash, beans, rice, and millet.