Are marine reptiles archosaurs?

Why is reproduction the most important part of the life cycle?

The ability to reproduce is the most fundamental part of the life cycle for any living species as it allows that species to multiply and evolve. Reproduction in animals either occurs asexually or with the help of sexual reproduction. Sexual reproduction involves both the male and the female form that particular species.

How are the three major reptile groups defined?

Each of the three major reptile groups are defined on the basis of the number and position of large openings in the temporal region of the skull behind the eyes (relative to other skull bones). Anapsid reptiles have no large openings in the temporal region of the skull and were the first stem to branch off the reptilian lineage.

Does a crocodile have a 4 chambered heart?

Crocodile, just like birds and mammals, are a separate class, that has been derived from reptiles. Mammalian four-chambered hearts come from the reptile-like three-chambered heart with an extension of the septum (the wall dividing the chambers) and there is the loss of the right systemic arch while the left systemic arch persists.

Why is the Late Cretaceous period important?

It was a time in which many new species came into existence, and when differences from region to region made the planet look more like it does today. The late cretaceous period saw most of the most extreme changes and was the time when the controversial event that wiped out the dinosaurs occurred.

What was the climate like during the Cretaceous period?

The entire cretaceous period spanned from 145 to 65.5 million years ago. During the first few million years of this period, the climate remained similar to what it had been during the earlier Jurassic period. As the end of the period approached, however, climate changes caused a number of species to go extinct, while other types emerged.

When did the Cretaceous period start and end?

Cretaceous Period. The Cretaceous began 145.0 million years ago and ended 66 million years ago; it followed the Jurassic Period and was succeeded by the Paleogene Period (the first of the two periods into which the Tertiary Period was divided). The Cretaceous is the longest period of the Phanerozoic Eon.

Why is the Mesozoic called the age of the dinosaurs?

This is why the Mesozoic Era is called the Age of the Dinosaurs. During the next mass extinction, which occurred at the end of the Mesozoic Era, all of the dinosaurs went extinct. Many other reptiles survived, however, and they eventually gave rise to modern reptiles.

What is the role of sexual reproduction in evolution?

In sexual reproduction, the genetic material of two individuals from the same species combines to produce genetically-different offspring; this ensures mixing of the gene pool of the species.

What is reproduction in biology?

Biology portal. v. t. e. Reproduction (or procreation or breeding) is the biological process by which new individual organisms – “offspring” – are produced from their “parents”. Reproduction is a fundamental feature of all known life; each individual organism exists as the result of reproduction. There are two forms of reproduction: asexual

How does sexual reproduction take place in multicellular organisms?

Sexual reproduction takes many forms in multicellular organisms. However, at some point in each type of life cycle, meiosis produces haploid cells that will fuse with the haploid cell of another organism.

Are crocodiles reptiles or amphibians?

Crocodiles are reptiles and not amphibians. It’s easy to mistake amphibians and crocodiles as reptiles of their class and amphibians of the class produce eggs as well and have cold-blooded. Yet, despite this similarity, there is a difference.

What is the difference between a crocodile and a reptiles heart?

Reptiles tend to have a three chambered heart i.e,they have a common ventricle because of incompletely developed septum.But crocodile inspite of being a reptile has a completely developed septum due to which the ventricle is divided into right and left ventricle.

Do crocodiles have 4 chambers in their heart?

They do have four chambers in their heart yes as well as two ventricles which is very unusual in reptiles.I expect crocodiles adapted to have a heart like this, because they evolved from smaller reptiles which don’t have a four chambered heart.

Which vertebrate has the most complicated blood circulation?

The crocodile has the most complicated blood circulation of all vertebrates. They do have four chambers in their heart yes as well as two ventricles which is very unusual in reptiles.

Do crocodiles have a four chambered heart?

They do have four chambers in their heart yes as well as two ventricles which is very unusual in reptiles. I expect crocodiles adapted to have a heart like this, because they evolved from smaller reptiles which don’t have a four chambered heart.

How has a crocodile adapted to have a heart like this?

Crocodiles adapted to have a heart like this, because they evolved from smaller reptiles which don’t have a four chambered heart. They had to adapt their hearts because they are an unusual reptiles that spend a lot of their time in water.

How old are the rock beds of the Cretaceous period?

As with other older geologic periods, the rock beds of the Cretaceous are well identified but the exact age of the system’s base is uncertain by a few million years. No great extinction or burst of diversity separates the Cretaceous from the Jurassic.

What led to the mass extinction of the Cretaceous period?

Tyrannosaurus rex is part of the carnivorous groups of dinosaurs that, according to new research, maintained a stable level of biodiversity leading up to the mass extinction at the end of the Cretaceous. (Image: © AMNH/J. Brougham) The Cretaceous Period was the last and longest segment of the Mesozoic Era.

How did plants change during the Cretaceous period?

During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth by the end of the Cretaceous, coincident with the decline and extinction of previously widespread gymnosperm groups.

What is the Late Cretaceous period?

The late cretaceous period is a time span roughly 99.6 to 65.5 million years ago. The entire cretaceous period spanned from 145 to 65.5 million years ago.

What did the earth look like during the Cretaceous period?

Cretaceous Period Information. What did the earth look during you period? The earth looked like a vegetated jungle, which made it easy for animals to adapt and/or live during this time. Until about 66 million years ago, a large asteroid slammed into the earth, making it a completely desolate place.

What was Australia like in the Cretaceous period?

A typical landscape of the late Cretaceous Period, c75 million years ago. Image: Karen Carr Australia was joined to Antarctica, New Zealand and South America, forming the last remnant of the great southern landmass called Gondwana.

What is the Mesozoic era timeline?

Mesozoic Era Timeline and Important Facts. Spanning around 200 million years, the Mesozoic Era was characterized by rapid evolution of life on the Earth, most noteworthy being the rise and fall of the dinosaurs.