For this topic, you will choose one (1) topic from the attached list and constru

Question

For this topic, you will choose one (1) topic from the attached list and construct a one-page concept sketch. Remember that a concept sketch consists of a sketch (or series of sketches), labels, and complete sentences written around the sketch describing the important processes or parts of the sketch.

Great Dying: what it is, when it occurred, what types of life it affected, and a summary and evaluation of each of the possible causes

Earliest dinosaurs and their ancestors: what they were, when they lived, what factors led to the dominance of dinosaurs

Jurassic and Cretaceous dinosaurs: the names and characteristics of the main types, and how they lived

Ammonites: what they were, where and how they lived, their variation in characteristics with time, and importance for determining the ages of Mesozoic rocks

Rudist reefs: what they are, what types of organisms form them, how they are expressed in the rock record and some examples

Rocks and fossils of the Petrified Forest and Painted Desert (AZ): the age, name, and sequence of rocks, the environments in which they are interpreted to have formed, and how the geologic events led to these places

Dinosaur National Park (UT-CO): the age, name, and sequence of rocks, the environments in which they are interpreted to have formed, and how later geologic events affected the rock layers

Early mammals: what they were, when they lived, how they lived, and what later creatures are related to them

Rise of angiosperm (flowering plants): when this type of plant first developed, what the characteristics are, how they are expressed in the rock record (including pollen), and how they changed the appearance of landscapes and the behavior of creatures

Explanation / Answer

AMMONITES:-

These are basically mollusc which have already extinct. They are in the subclass Ammonoidea and of the class Cephalopoda and phyllum Mollusca. They are most useful index fossils and are found to very specific Geological time period.

ECOLOGY AND HABITAT:-

They used to live in open water of ancient seas. Among the species there are no bottom dwellers found. They adopted nice swimming capabolity having a discus-shaped. Some were found to be less effective swimmers too.

VARIATION OF CHARACTERS WITH TIME:-

The tradition of homeomorphy is significantly found in Ammonites, which means morphology is repeated through time.So the genera related to the species from different ages are quite similar. Example:Mid Jurassic Kosmoceras and the Early Cretaceous Euhoplite. The Ammonite shells are divided into chambers separated by septa. The Ammonite lives in the last body chamber which are filled with gas and fluids.

DISTRIBUTION:-

Although Ammonites are index fossil of Mesozoic era, they were abundant from the Mid Devonian. The K-PG extinction event marking theend of the cretaceous period had resulted the complete extinction of Ammonites along with dinosaurs. These are very reliable information for determining Mesozoic era using Ammonites as an index fossil.

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