Living Fossils
Living Fossils
Wollemi
Pine
Sea Pen
Horshoe Crab
Stromatolites
A "living fossil" is a creature that has survived pretty well "unchanged" for millions of years and is still present with living specimens on earth today
Australia's own living fossil - The Wollemi Pine - from 50 million years ago
Wollemi Pine is believed to exist in only one location which is within 200 km of the heart of Sydney, Australia's largest city. There are less than 40 trees in the wild.
This makes it one of the rarest plants in the world. It belongs in the plant family Araucariaceae but has distinctive features.
However it has very different features from any known living pine.
Its closest relatives are probably the extinct pines which were a dominant feature of the landscape of what is now Australia during the Jurassic and Cretaceous Periods - between 200 and 65 million years ago.
These pines are known to us only from fossils.
Conifers tend to be dark green but the leaves of Wollemi Pine are a light green - varying from bright lime green on younger foliage to apple green on mature foliage. The leaf structure is extremely complex and unusual. The upper branches of the trees are tipped with bright green female cones and brown, cylindrical, male cones (the trees are bisexual).
The trunks of Wollemi Pine have a highly unusual brown, knobby cork-like bark which has led it to being dubbed 'the Coco Pops tree'. Indeed it appears to be a true "living fossil", most closely related to extinct species of Araucariaceae in the fossil record in southern Australia about 50 million years ago. The family Araucariaceae is an important group in studying the history of our flora. Araucariaceae had a world-wide distribution in the Jurassic and Cretaceous periods 200 to 65 million years ago. Since the great extinctions at the end of the Cretaceous period,
Araucariaceae have survived only in the southern hemisphere. The present occurence suggest a Gondwanic distribution, linked to the time when Australia, New Zealand, Africa, South America and India were all parts of the great supercontinent Gondwana. Wollemi Pine, is so distinctive that it represents a new genus and must have been an evolutionary line distinct from any other surviving plant group for at least 65 million years. The new plant is related to Araucaria, which includes Australia's Hoop Pine and Bunya Pine and the Norfolk Island Pine, and also to Agathis including the Kauri Pine of New Zealand. Wollemi Pine is a conifer ('pine') whose nearest living relatives are native pines of Australia and New Zealand: Hoop Pine, Bunya Pine, and Norfolk Island Pine.
The single known population of Wollemi Pine is in a rainforest gully within Wollemi National Park (487,648 ha). This is the State's largest wilderness area - located West of the Putty Road between Sydney and the Hunter Valley.
The mature plants are between 27 and 35 metres high with trunks up to 1 metre in diameter. However the tree can grow taller: one fallen trunk is 38 metres long. During the Jurassic Period (208 - 144 million years ago), the continental mass which we call Australia was part of the great supercontinent of Gondwana, towgether with Africa, South America and India. What is now the east coast of Australia lay close to the South Pole, but worldwide climates were uniformly warm to hot and wet.
From the Cretaceous Period (144 - 66.4 million years ago) modern flowering plants began to evolve and gradually displace the conifers in the Southern Hemisphere. Because of the extreme danger to the plant from illegal seed collecting, the location of the population is being kept secret.
Sea Pen
Some Ediacaran fossils appear somewhat similar to modern organisms. For example, Charnia resembles the modern sea pen, a feathery soft coral.The Ediacaran is dated between 635 and 540 million years ago. It preceded the Cambrian period, about 540 to 485 million years ago, which marked the beginning of one of the biggest explosions of life in the history of Earth.
For a long time, scientists thought the Cambrian period was when multicellular life first ran rampant. It is when most of the known kinds of animals that scientists recognize today first appeared on the scene. Yet late in the 20th century, researchers discovered fossil evidence of multicellular organisms in the Ediacaran as well, pushing back their first appearance almost 100 million years.
Horsehoe Crab
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Four species of horseshoe crabs exist today. Only one species, Limulus polyphemus, is found in North America along the Atlantic and Gulf coasts from Maine to Mexico. The other three species are found in Southeast Asia. Horseshoe crabs are not true crabs at all. Horseshoe crabs are more closely related to arachnids (a group that includes spiders and scorpions) than to crustaceans (a group that includes true crabs, lobsters, and shrimp). Horseshoe crabs are often called "living fossils" because fossils of their ancestors date back almost 450 million years--that's 200 million years before dinosaurs existed.
Despite inhabiting the planet for so long, horseshoe crab body forms have changed very little over all of those years. The strange anatomy of the horseshoe crab is one of this animal's most notable aspects. Unfortunately, the long, thin, spike-like tail of horseshoe crabs has given this species an unfavorable reputation. Many people view horseshoe crabs as dangerous animals because they have sharp tails. In reality, horseshoe crabs are harmless. Their tails are used primarily to flip themselves upright if they are accidentally overturned.
Stromatolites
Stromalolites are are layered mounds, columns, and sheet-like sedimentary rocks.
They were originally formed by the growth of layer upon layer of cyanobacteria, a single-celled photosynthesizing microbe
Live Stromalolites from Shark Bay Western Australia
Ancient Stromatolite - The age is estimated to be 2.2 to 2.4 billion years old, near the Lower Paleoproterozoic,
from a time in the Precambrian when stromatolite is believed to have been both ubiquitous and abundant on earth.