Analyze the Ordovician and Silurian periods, typical representatives of trilobites in the fauna, and its ecosystem.
Preface, during the late Silurian period, many famous biota appeared, including fish, invertebrates and plants.
In the late Silurian period, large-scale radiation began to occur in fish. The most representative are speartail fish and hard scale fish. Speartail fish were the first teleost fish to appear, with features such as two dorsal fins, two fins and hard scales. Hard-scaled fish are a group of fish with hard bones and scales, including ancient sharks, plate fish and lungfish.
Trilobites are one of the most significant invertebrate fauna in Ordovician and Silurian marine ecosystems. Their bodies consist of a cephalothorax and a tail, with three body segments each, each with a pair of appendages. Trilobite fossils are very common in rocks, so they have also become an important material for stratigraphic and paleoecological research.
During the Ordovician and Silurian periods, plants on land gradually became richer. Initially land plants were mainly low bryophytes and ferns, but over time tall gymnosperms and angiosperms also began to appear.
During the Ordovician and Silurian periods, arthropods became one of the most prominent fauna in marine ecosystems. They include trilobites, crustaceans, polypods and chelae. These arthropod fossils are also very important in stratigraphic and paleoecological studies.
During the Ordovician and Silurian periods, seaweed also began to show large-scale radiation. Initially seaweed was mainly single-celled cyanobacteria and green algae, and over time, multicellular seaweed also began to appear.
Brachiopods were an important group of invertebrates of the Ordovician and Silurian periods. They have a hard exoskeleton and knotted appendages and play an important role in marine ecosystems. At the same time, brachiopod fossils have also become important materials for stratigraphy and paleoecological research.
In the late Silurian period, the first true terrestrial vertebrates—often referred to as "archaeans"—began to appear. These ancient fish have lungs and bimodal fins and are able to survive on land. At the same time, the radiation of aquatic vertebrates has been further expanded, including sharks, plate fish and lungfish.
The emergence and radiation of these biota marked the peak of the Ordovician and Silurian biota. The evolution and radiation of these biota not only reflect the changes in the earth's ecosystem at that time, but also have important reference value for today's biodiversity research.
Brachiopods of the Ordovician and Silurian periods include trilobites, hornstones, sea lilies, etc. They have a hard exoskeleton and knotted appendages and play an important role in marine ecosystems. At the same time, brachiopod fossils have also become important materials for stratigraphy and paleoecological research.
Ciliated animals of the Ordovician and Silurian periods included sponges, corals, etc. They are usually fixed living sea creatures with hard shells and complex internal structures. At the same time, corals are an important component of today's coral reef ecosystems.
Molluss of the Ordovician and Silurian periods included conchs, gastropods, cephalopods, etc. They are usually invertebrate sea creatures with soft bodies and different forms of shells.
Arthropods of the Ordovician and Silurian periods include trilobites, lysophiles, beetles, etc. They have distinct arthropods and rigid exoskeletons, and are widely distributed both in the sea and on land.
In the late Silurian period, the first true terrestrial vertebrates—often referred to as "archaeans"—began to appear. These ancient fish have lungs and bimodal fins and are able to survive on land. At the same time, the radiation of aquatic vertebrates has been further expanded, including sharks, plate fish and lungfish.
These typical representatives reflect the diversity and complexity of the Ordovician and Silurian biota, which are of great significance for the study of paleontology and understanding of ecosystem changes at that time.
Bibliography:
Conway Morris, S. (1998). The crucible of creation: the Burgess Shale and the rise of animals. Oxford University Press.
