The Paleozoic (or Palaeozoic) Era (from the Greek palaios (παλαιός), "old" and zoe (ζωή), "life", meaning "ancient life") is the earliest of three geologic eras of the Phanerozoic Eon, spanning from roughly 541 to 252.2 million years ago (ICS, 2004).
The Paleozoic was a time of dramatic geological, climatic, and evolutionary change, it was dominated by various forms of organisms. Great forests of primitive plants covered the continents, many of which formed the coal beds of Europe and eastern North America.
Towards the end of the era, large, sophisticated reptiles were dominant and the first modern plants (conifers) appeared. The first vertebrates appeared in the form of primitive fish, which greatly diversified in the Silurian and Devonian.
The first animals to venture onto dry land were the arthropods. Some fish had lungs and strong, bony fins and could crawl onto the land also.
Pterygotus, which lived from the Early Silurian to Devonian periods, were characterised by small to large exoskeletons with semilunar scales. The tail was expanded, or flatter than it was tall. Pterygotids also had claws in front of the mouth that were large and long, with strong, well developed teeth on the claws. Their walking legs were small and slender, without spines.
Pterygotus is distinguishable from other pterygotids by the curved distal margin of the chelae. The head is a trapezoid with rounded corners, with compound eyes located near the edge of the front corners. The tail has a keel running down its centre, terminating in a short spine.
It was one of the top predators in the Paleozoic seas. It lived in shallow coastal areas, hunting fish, and other animals using stealth. It would have ambushed its prey by burying itself in sand. Then, when a fish or other unwitting animals came within range, Pterygotus would rise up and grab it with its claws. Fossils have been found in all continents.
The Agave sisalana, is a species of Agave native to southern Mexico but widely cultivated and naturalized in many other countries.
It yields a stiff fibre used in making various products. The term sisal may refer either to the plant's common name or the fibre, depending on the context.
The sisal fibre is traditionally used for rope and twine, and has many other uses, including: paper, cloth, wall coverings, carpets, and dartboards.
Coccosteus is an extinct genus of arthrodire placoderm. Its fossils have been found throughout Europe and North America.
Coccosteus had a joint between the armour of the body and skull. In addition, it also had an internal joint between its neck vertebrae and the back of the skull, allowing for the mouth to be opened even wider. Along with the longer jaws, this allowed Coccosteus to feed on fairly large prey.
The up-and-down movement of the skull also allowed for more water to be pumped through the gills.
Possibly, the creature supplemented its diet with organic material filtered from mud using the gills.
Cephalaspis was a genus in the class Osteostraci of Palaeozoic armoured jawless fishes, or ostracoderms. It was a medium sized detritivorous fish that lived in freshwater streams and estuaries of the early Devonian.
Cephalaspis was heavily armoured, presumably to defend against predatory placoderms and eurypterids, as well as to serve as a source of calcium for metabolic functions in calcium-poor freshwater environments. It had sensory patches along the rim and centre of its head shield, which were used to sense for worms and other burrowing organisms in the mud.
Cephalaspis easily stirring sand and dust into the water, along with revealing the hiding places of its prey, digging up worms or crustaceans hidden in the mud and algae, as well as sifting through detritus.
Araucaria heterophylla (synonym A. excelsa) is a distinctive conifer, a member of the ancient and now disjointly distributed family Araucariaceae.
As its vernacular name Norfolk Island pine implies, the tree is endemic to Norfolk Island, a small island in the Pacific Ocean between Australia, New Zealand and New Caledonia.
The genus Araucaria occurs across the South Pacific, especially concentrated in New Caledonia (where 13 closely related and similar-appearing species are found. It is sometimes called a star pine, triangle tree or living Christmas tree, due to its symmetrical shape as a sapling, although it is not a true pine.
Eryops is a genus of extinct, semi-aquatic temnospondyl amphibian found primarily in the Lower Permian-age. Eryops averaged a little over 1.5-2.0 meters (5–6.5 ft) long, making it one of the largest land animals of its time. It weighed about 90 kilograms (200 lb). It probably had few predators, although it would have likely been preyed upon by Dimetrodon, which was larger and was the apex predator at the time.
Several complete skeletons of Eryops have been found in the Lower Permian, but skull bones and teeth are the most common fossils.
Eryops was better adapted to a terrestrial environment than its ancestors. Sturdy limbs and a strong spine supported the body while out of water.
Peruvian pepper (Schinus molle, also known as American pepper, Peruvian peppertree, escobilla, false pepper, molle del Peru, pepper tree, peppercorn tree, Californian pepper tree, pirul and Peruvian mastic) is an evergreen tree that grows to 15 meters (50 feet).
It is native to the Peruvian Andes. The bright pink fruits of Schinus molle are often sold as "pink peppercorns" although S. molle is unrelated to true pepper.
Moschops is an extinct genus of therapsid that lived in the Guadalupian epoch, around 265–260 million years ago. Therapsids are synapsids, which were at one time the dominant land animals. Its remains were found in the Karoo region of South Africa.
Moschops had a short, thick and massive head, which was broad across the orbits. The occiput was broad and deep, but the skull was more narrow in the dorsal border. Furthermore, the pterygoid arches and the angular region of the jaw were quite heavy, allowing the insertion of strong jaw muscles. Due to that and because it possessed long-crowned, stout teeth, it is believed that Moschops was a herbivore feeding on nutrient-poor and tough vegetation, like cycad stems.
Phytolacca dioica, is a massive evergreen tree native to the Pampa of South America. It has an umbrella-like canopy that spreads to a girth of 12 to 15 meters (40 to 50 feet) and can attain a height of 12 to 18 meters (40 to 60 feet).
Because it is derived from herbaceous ancestors, its trunk consists of anomalous secondary thickening rather than true wood. As a result, the ombú grows fast but its wood is soft and spongy enough to be cut with a knife.
These properties have led it to be used in the art of bonsai, as it is easily manipulated to create the desired effect.
Dimetrodon is an extinct genus of synapsid that lived during the Early Permian. The most prominent feature of Dimetrodon is the large sail on its back formed by elongated spines extending from the vertebrae.
It walked on four legs and had a tall, curved skull with large teeth of different sizes set along the jaws.
A single large opening on either side of the back of the skull links Dimetrodon with mammals and distinguishes it from most of the earliest sauropsids, which either lack openings or have two openings.
Features such as ridges on the inside of the nasal cavity and a ridge at the back of the lower jaw are thought to be part of an evolutionary progression from early tetrapods (four-limbed vertebrates) to mammals.
Aloe is a genus containing over 500 species of flowering succulent plants. The most widely known species is Aloe vera, or "true aloe", so called because, though probably extinct in the wild, it is cultivated as the standard source of so-called "aloe vera" for assorted pharmaceutical purposes. Other species, such as Aloe ferox, also are cultivated or harvested from the wild for similar applications.
Sauroctonus lived in the Late Permian epoch before the Permian-Triassic extinction event that wiped out many life forms on Earth.
Sauroctonus's flattened, triangular skull was about 25cm long, with a parietal eye, a primitive character, on the crown. The upper and lower jaw each contained one pair of massive canines (the upper pair was larger); the other teeth were smaller, but were also sharp and pointed. In addition, minute, blunt teeth were present on the palatine bones. The lower jaw was widened to form a kind of chin. The long, lightly built, five-toed limbs bore a resemblance to mammals' limbs, but despite its 'mammalian' characteristics, Sauroctonus was not one of the ancestors of mammals. Its fossils have been found in South Africa and the Volga basin of Russia.
Fully grown, Atlas cedar is a large coniferous evergreen tree, 30–35 m (rarely 40m) tall, with a trunk diameter of 1.5–2 m.It is very similar in all characters to the other varieties of Lebanon cedar; differences are hard to discern. There are also fastigiate, pendulous, and golden-leaf forms in cultivation. The Atlas cedar is useful in cultivation because it is more tolerant of dry and hot conditions than most conifers.
Many (but far from all) of the cultivated trees have glaucous (bluish) foliage, more downy shoots, and can have more leaves in each whorl; young trees in cultivation often have more ascending branches than many cultivated Cedrus atlantica.
Scutosaurus was a genus of armor-covered pareiasaur. Its genus name refers to large plates of armor scattered across its body. It was a large anapsid reptile that, unlike most reptiles, held its legs underneath its body to support its great weight.
Scutosaurus was heavy, and its short legs meant that it could not move at speed for long periods of time, which made it vulnerable to attack by large predators.
To defend itself Scutosaurus had a thick skeleton covered with powerful muscles, especially in the neck region. Scutosaurus lived around 254-252 million years ago in Russia, in the later Permian period
Yucca is a genus of perennial shrubs and trees in the family Asparagaceae, subfamily Agavoideae. They are native to the hot and dry (arid) parts of North America, Central America, South America, and the Caribbean.
Yuccas are widely grown as ornamental plants in gardens. Many species also bear edible parts, including fruits, seeds, flowers, flowering stems, and more rarely roots.
Dried yucca leaves and trunk fibers have a low ignition temperature, making the plant desirable for use in starting fires via friction. In rural Appalachian areas, species such as Yucca filamentosa are referred to as "meat hangers".