Everything Life Sciences Grade 10

CHAPTER 11 History of Life on Earth 11.1 Overview 314 11.2 Representations of life’s history 314 11.3 Life’s History 323 11.4 Ma ...

11 History of Life on Earth 11.1 Overview Introduction DUMMY Inthis chapter we will learn about the history of life on Earth. We ...

evolution of life forms over time through examining thefossil record. Geologicaltimescale DUMMY Thegeological timescale is a ’ca ...

FACT http: //deeptime.info/ This website has an ‘infographic’ showing geological time on a clock. Each hour on the clock corresp ...

Mesozoic,Paleozoic and Cenozoic eras Two major climate changes characteristic of each era you show on your timescale and mentio ...

FACT Natural selection is a process you will learn about in more detail in Grades 11 and 12. FACT WATCH: This explains how natur ...

fossils are skeleton or parts of skeletons or leaf or animal imprints embedded in and preserved in the Earth’s crust. The study ...

FACT If the rocks surrounding a fossil are distorted and squeezed by geological forces, it will result in distortion of the foss ...

Radiometric or Radiocarbon dating Relative Dating Radiometric Dating Radiometric dating relies on measuring the amount of car ...

Deductive reasoning to understand the past DUMMY Deductive reasoning combines the use of evidence and theories to make deduction ...

11.3 Life’s History Pre-Cambrian DUMMY Hadean: the Earth we live on is approximately 4,6 billion years old. The conditions that ...

Archean: when life in the form of uni-cellular organisms first developed, the Earth’s early atmosphere consisted entirely of vol ...

FACT Approximately 850–630 million years ago, a ’global glaciation’ event is thought to have occurred, also known as an ’Snowbal ...

FACT Hard shells fossilise more readily than soft bodied organisms, as they are better at resisting decay, take significantly lo ...

FACT Cycads occur across much of the subtropical and tropical parts of the world including here in South Africa where their evol ...

FACT The existing sequoia trees found mainly in the United States were also thought to have evolved in the Mesozoic. Figure 11.1 ...

FACT In Grade 12 you will learn study in great detail the course of human evolution to gain a firm understanding of how we evolv ...

FACT Philip Tobias (October 1925–June 2012) was a South African palaeoan- thropologist at University of Witwatersrand whose work ...

Figure 11.13: Phillip Tobias, South African anti- apartheid activist, world-famous palaeoanthropolo- gist. FACT The Golden Toad ...

Causesof mass extinctions DUMMY There is still a lot of debate among scientists as to what caused the mass extinctions. To be a ...