05 geologic timeline (1)

Powerpoint for Earth and Life Science - Geologic Timeline

1. Geologic Timeline Prepared by: Engr. Andreana Amor Gulay Engr. Ariel S. Motas

2. How important is your past to who you are today?

3. Geologic Timeline “calendar” for events in Earth’s history. it serves as standard timeline used to describe the age of rocks, fossils, and the events that formed them. A device which is of great help to the science of geology owed to the explorations and studied made by the geologists that were recorded . The geologic time scale provides a system of chronologic measurement relating stratigraphy to time that is used by geologists, paleontologists and other Earth scientists to describe the timing and relationships between events that have occurred during the history of the Earth.

4. The necessity of knowing how life began in the past, the events, and principles behind the Earth’s history enable us to conform with the alterations or consequences that we might encounter or experience in the near future. As a part of the new generation, we should be appreciative and accept that all things that are present in our time were the outcome of Earth’s history.

5. Division of Geologic Timescale Eras are subdivided into periods ...periods are subdivided into epochs . EONS First and largest division of geologic time Greatest expanse of time Four eons • Phanerozoic ("visible life") –most recent eon • Proterozoic • Archean • Hadean – the oldest eon

6. Division of Geologic Timescale ERAS Second division of geologic time PERIODS T hird division of the geologic time. Named for either location or characteristics of the defining rock formations EPOCHS Fourth division of geologic time Represents the subdivisions of a period

7. Paleozoic Era It is the beginning of early life . All of the continents had come together to form the supercontinent called Pangea . It is characterized by rapid development of terrestrial plants . Devonian period is known as the age of fishes.

8. Paleozoic Era At the end of the Paleozoic, the largest mass extinction in history wiped out approximately 90 % of all marine animal species and 70% of land animals. – Possible causes of this Mass Extinction Event • Lowering of sea levels when the continents were rejoined as Pangaea (convergent boundary) • Increased volcanic activity (ash and dust) • Climate changes – cooler climate

9. Mesozoic Era – Middle Life At the beginning of this era the continents were joined as Pangaea. Pangaea broke up around the middle of this era. Pangea rifted into Laurasia and Gondwanaland . Reptiles became the most abundant animals because of their ability to adapt to the drier climate of the Mesozoic Era. – Skin maintains body fluids – Embryos live in shells

10. Mesozoic Era – Middle Life Dinosaurs were also very active in this era . – First small dinosaurs appeared in the Triassic Period . – Larger and more abundant dinosaurs appeared in the Jurassic Period. Small mammals and birds also appeared during this era. – The mammals were small, warm-blooded animals . Hair covering their bodies. These characteristics help them survive in changing environments.

11. Mesozoic Era – Middle Life The main plant life of this time were Gymnosperms or plants that produce seeds, but no flowers. – Pine Trees Flowering plants appeared during the END of this era

12. Mesozoic Era This era ended with a mass extinction event about 65 million years ago. – Many groups of animals, including the dinosaurs disappeared suddenly at this time. Meteorite Impact Hypothesis

13. Cenozoic Era – Recent Life It is also known as the age of recent life or age of mammals . It has the most complete record of any era because the rocks are more accessible. Began about 65 million years ago and continues today !!!!! – Climate was warm and mild. – Marine animals such as whales and dolphins evolved. Mammals began to increase and evolve adaptations that allowed them to live in many different environments – land, air and the sea . – Grasses increased and provided a food source for grazing animals

14. Cenozoic Era Many mountain ranges formed during the Cenozoic Era – Alps in Europe and Himalayas in India; Rocky Mountains in the USA. Growth of these mountains may have helped to cool down the climate – Ice Ages occurred late in the Cenozoic Era (Quaternary Period ). As the climate changed, the animals had to adapt to the rise and fall of the oceans caused by melting glaciers.