Plant Dating Game Through Time

Bruce Crawford March 21, 2015 Director, Rutgers Gardens www.rutgersgardens.rutgers.edu

Oldest living organism – Bacteria, at least 3.2 Billion years old! Fungi probably colonized the land during the Cambrian (542–488.3 MYA), long before land plants Ferns Initially developed around 350 Million Years Ago (MYA), although the ferns that we know date back 250 million years or sooner.

Problem: Lack flowers and seeds, but produce spores and a temporary plant form called a prothallus that produces eggs and sperm.

Bar of choice: Water Bar

Attraction: Malic Acid

Gymnosperms Initially developed around 300 MYA and are represented today by the Pines, Cycads and the Ginkgo. Gymnosperm literally means naked (Gumnós) seed (Spérma).

Problem: Lack attractive flowers, but they do produce individual male pollen baring cones and female or ovule bearing cone.

Bar of choice: Windy Bar

Attraction: Pure luck!

Angiosperms There is a great deal of confusion as to when they initially developed but, it is between 160 and 140 MYA. The world was starting to cool down and the Ferns and Gymnosperms were having trouble with the change in ‘Management’. Angiosperm means seed (Spérma) contained within a vessel (Angeîon)

Problem: Relatively few to start, it was a lonely bar with lots of ‘Lonely Eyes” – that changed!

Bar of choice: Bug Bar

Attraction: Make-up! Color, nectaries, high protein pollen, high water vapor, fragrance

Grasses Developed about 65 Million Years Ago during periods of reduced rainfall.

Problem: Flowers are a bit less colorful attractive

Bar of choice: Windy Bar

Attraction: Once again, back to pure luck!

Devonian 419-358 MYA (Average O2 levels at 15% vs today’s 21%) First fossilized evidence of Lichens (a symbiotic relationship between fungus and photosynthetic algae) and Liverworts

The early part of this period was characterized by plants that did not have roots or leaves like the plants most common today and many had no vascular tissue at all. They probably spread largely by vegetative growth, and did not grow much more than a few centimeters tall due to this a poorly developed vascular system.

Wattieza (now extinct) appeared around 385 MYA and it had a better developed vascular system and stood to heights of 34’ and resembled a modern day tree fern.

Marks the appearance of tetrapods or four limbed vertebrates.

Carboniferous 358-299 MYA (O2 at 35%) Plants Lycopodium, Equisetum, Cycads (appeared about 300 MYA), ferns and the beginning of the true Conifers (in the genus Walchia)

Mosses – developed around 350 MYA. Mosses lack vascular tissue, much like the original terrestrial or land plants, so they could not transport water, sugars or minerals around the plant. The first appearance of stomata is in Mosses as the earlier Liverworts do not possess stomata.

Ferns - Initially developed around 350 Million Years Ago, although the ferns that we know in our gardens date back 250 million years (Osmunda) or sooner – many appeared after 100 MYA. Lack flowers and seeds, but produce spores and a temporary plant form called a prothallus that produces egg and sperm. Malic Acid serves as the perfume for attracting the sperm to the ovum.

Towards the end of the Carboniferous period, fossil remains have been found of air-breathing insects, myriopods (like millipedes) arachnids (Spiders), insects similar to the modern day cockroach and weevils. The cycads have been generally thought to be wind pollinated. However, several recent studies in different regions indicate that cycads are mostly insect pollinated, often by weevils that are closely dependent on the cycads. The insects perform the pollination and the cycads in turn offer the insects food, shelter, a breeding site, and larvae protection. This contrasts with both Ginkgo and the conifers (the other primitive seed plants), all of which are wind pollinated. Chemistry of the pollinator-attractants in cycads is markedly different from that of any flowering plants, suggesting that insect pollination has evolved independently in the two groups. ‘Innovations’ in plant development include: wood, seeds, integuments (husks or ‘skin’ of a seed), pollen tube, pollen grain, cork cambium, vascular cambium.

Amphibians were large and abundant

Permian Period: 299 to 250 MYA (O2 at 23%) The first modern trees (conifers, ginkgos and younger cycads) appeared in the Permian.

Gymnosperms, have two spore types, the microspores and megaspores, which are produced in the pollen cones or ovulate cones, respectively. Pollen grains mature from microspores, and ultimately produce sperm cells while ovules develop from megaspores and are retained within the ovule. During pollination, pollen grains are physically transferred between plants, from pollen cone to the ovule, being transferred by wind or insects. Whole grains enter each ovule through a microscopic gap in the ovule coat or integument called the micropyle. The pollen grains mature further inside the ovule and produce sperm cells. Two main modes of fertilization are found in gymnosperms. Cycads and Ginkgo have motile sperm that swim directly to the egg inside the ovule, whereas confers and gnetophytes have sperm with no flagella and they are conveyed to the egg via a pollen tube. After syngamy (joining of the sperm and egg cell), the zygote develops into an embryo (young sporophyte). More than one embryo is usually initiated in each gymnosperm seed. The mature seed comprises the embryo and the remains of the female gametophyte, which serves as a food supply, and the seed coat (integument).

Temperatures varied. At the start, temperatures were cool as the Ice Age from the end of the Carboniferous period was still retreating. As the glaciers retreated, the central areas of Pangea became drier and were prone to cyclical heating and cooling with the seasons. Gymnosperms flourished with the drier climate and ferns retreated in numbers.

Triassic Period: 250 to 200 MYA (O2 at 16%) The climate was warm and dry, with no ice at the poles. Winters were very cold. Plants: Cycads, Gingko, Conifers Conifers dominated in the northern hemisphere

Animals: First Dinosaur appeared in late Triassic, as did the first mammal-like animals and the first turtles! Mammals started to become a minority and became principally night dwelling creatures dining on insects – perhaps the cools nights promoted the growth of hair.

In the later part of the Triassic Period, the land mass started to split with Lauroasia to the North and Gondwana to the south.

Jurassic Period: 201to 145 MYA (O2 at 26%) Gymnopserms (conifers) dominated the forests and reptiles remained dominant.

During the late Jurassic, the first bird-like creatures appeared. Prior to that, Pterosaurs ruled the skies, from 220-65 MYA

Flowering Plants (Angiosperms) such as Water Lilies started to appear.

Cretaceous Period: 145-66 MYA (O2 at 16%) Marks the appearance of flowering trees and plants, including Archaefructus a 125 million years old fossil collected in Liaoning Province, China. Although it had no petals, this ancient flower had closed fruits that protected the seeds inside. This evolutionary leap separated flowering plants from other plants and probably led to their great success. Illustration on right by: Karina Simons and David Dilcher.

Original species include Waterlilies and Magnolias.

The angiosperms have been enormously successful and many of the modern families of ferns appeared.

There are now about 235,000 species of Angiosperms in comparison to just over 700 gymnosperms.

Ants, termites, aphids, gall wasps, cockroaches and grasshoppers first appeared.

Tyrannosaurus rex was active during the later period of the Cretaceous

The end of the Cretaceous Period is marked by a cooling of the earth and the vanishing of many of the dinosaurs, presumably due to a strike by a meteorite or comet.

Paleogene Period: 66-23 MYA (O2 at 26%) Saw the rise in Mammals and the increase in diversity of birds.

Bromeliads appeared around 70 MYA and continued to speciate heavily around 20 MYA as the Andes rose, grasses appeared about 65 MYA and Bamboos appeared around 30 MYA.

India was colliding with Asia and the Himalayas were developing. South America was drifting towards North America and Africa to Europe. Australia split off from Antarctica and was drifting north. The Atlantic Ocean was getting several centimeters wider each year.

Quaternary Period: 2.5 - 0 MYA (O2 levels at 21%) Human-like fossils appeared 190,000 years ago