Fossils and Geological Eras

Sphenopsida (like Calamites) were dominant in the Carboniferous period, not the Jurassic.

Sphenopsida are represented today by the genus Equisetum, so they are not extinct.

The Gymnosperms originated during the late paleozoic era but floursihed very well during mesozoic era. Hence, the mesozoic period is called as 'Age of Gymnosperms'.

During the Mesozoic era, specifically the Jurassic period approximately 200 million years ago, gymnosperms were the dominant land plants before the rise of angiosperms.

Olive Ridley sea turtles are often referred to as living fossils because their evolutionary lineage has remained largely unchanged for millions of years.

Sir Richard Owen, an English biologist and paleontologist, coined the term Dinosauria (meaning terrible lizard) in 1842.

The mass extinction event that wiped out the non-avian dinosaurs occurred approximately 65 to 66 million years ago at the end of the Cretaceous Period.

Dinosaurs first appeared during the Triassic Period (about 230 million years ago) and went extinct at the end of the Cretaceous Period (65 million years ago), spanning roughly 165 million years.

Sharks, crocodiles, and turtles have ancient lineages that date back to or before the time of dinosaurs. Bears, however, are mammals that evolved much later.

The earliest known dinosaurs appeared during the Triassic Period, roughly 230 million years ago.

The term dinosaur was coined by Richard Owen from the Greek words deinos (terrible or fearfully great) and sauros (lizard).

Mass extinctions are characterized by a sudden disappearance of many species from the fossil record, often indicating a catastrophic global event rather than a slow, gradual process.

The fossil record generally shows a progression from simpler, single-celled organisms in older layers to more complex, multicellular organisms in younger layers, supporting the theory of evolution.

Transitional fossils exhibit traits common to both an ancestral group and its derived descendant group, effectively filling the gap in the evolutionary record.

According to the law of superposition, younger rock layers are deposited on top of older ones; therefore, fossils in the newer layers are more likely to resemble modern organisms.