Fossils and Life Science Overview

Fossils

• Fossils are the preserved remains of plants and animals, whose bodies were buried in sediments.
• They also include preserved traces of life

Microfossils

• Microfossils are tiny remains of bacteria, protists, fungi, animals, and plants.

What is life science?

• Life science is a collection of disciplines consisting of the theories and principles that focus on the structure and function of living things, from the molecular to ecosystem levels.

Evolving Concepts of Life Based on Emerging Pieces of Evidences

• Concepts of life are based on new pieces of evidence and are constantly evolving.

Primordial Soup Theory

• Proposed by Alexander Oparin and John Haldane
• Life started in a primordial soup of organic molecules energized by energy from Earth's early atmosphere.
• Organic molecules were created by this process.

Timeline of Appearance of Life Forms

• A timeline showcasing the appearance of various life forms over time.

Hadean (Early Earth Development)

• The Hadean Era spanned from 4.6 to 3.8 billion years ago.
• Early Earth was a violent place, with frequent meteor impacts and volcanic eruptions.
• These conditions created zircon crystals.

Archean (Period of Appearance of the First Prokaryotes)

• The Archean period began 3.5 billion years ago.
• During this era, life on Earth started with prokaryotes, which were discovered in sedimentary rocks called stromatolites.

Proterozoic Eon (Period of Appearance of the First Eukaryotes)

• The Proterozoic eon encompasses a period when the first eukaryotes emerged, marking a significant leap in life's complexity and evolution.
• The emergence of multicellular organisms also occurred during this time.

2 Billion Years Ago

• Eukaryotes first appeared.
• Multicellular organisms flourished.

Paleozoic Era (Dominance of Appearance of the First Trilobites)

• The Paleozoic era represented a pivotal period characterized by the significant emergence and dominance of trilobites and cephalopods in the ocean.
  • Notably, this occurred during the Cambrian and Ordovician periods.

Mesozoic Era (Dominance of Dinosaurs)

• This era lasted from 251 to 65.5 million years ago.
• Dinosaurs were the dominant reptiles during the Triassic, Jurassic, and Cretaceous periods.

Cenozoic Era (Recent Life)

• Starting 65.5 million years ago, the age of mammals, plants, and animals that resemble those seen today.
• Homo erectus (A hominid) evolved.

250 Thousand Years AGO

• Recent time and the age of mammals with plants and animals resembling those today.

Genus Homo

• Modern humans emerged from this genus.
• One of the first signs of Homo development was the use of stone tools.

Amniotes

• Amniotes are the first mammals.
• They evolved to be the direct ancestors to modern mammals

Eozostron

• The Earliest known mammals were Eozostron.

A Marine Animal First Evolved

• A marine animal first appeared during the Cambrian period.

Extinct Species of the Genus Homo

• The extinct species of the genus Homo are the predecessors to modern humans.
• The modern human lineage developed from these species.

A Basic Cell Type that Lacks a True Nucleus

• Prokaryotes.
• A basic cellular type without a true nucleus.

Giant Reptiles that Roamed the Earth

• Giant reptiles ruled the earth during the Mesozoic era.

This Basic Cell Type Contains a True Nucleus that Contains DNA

• Eukaryotes.
• The basic cellular type that has a true nucleus and contains DNA.

Blue Green Algae, First Photosynthetic Organisms

• The blue-green algae thrived during the Proterozoic Eon.
• These organisms were the first photosynthetic life forms.

First Crystal Formed During the Hadean Era

• Crystals formed during the Hadean Era.
• These crystals provided a record of the chemical characteristics of early rocks.

Mounds: Oldest Fossils Containing Life on Earth

• Stromatolites are the oldest known fossils containing life on Earth.

This is the Age of Dinosaurs

• Dinosaurs dominated the earth during the Mesozoic era.

Preserved Remains of Plants and Animals Buried in Sediments

• Fossils represent preserved remains of plants and animals entombed in sediments.