The origins of Life

• Biologie
• Middelbare school
• vwo
• Leerjaar 4

The Development of Life: Evolution

Learning Objectives

1. You can explain theories on how life could have originated on Earth.
2. You can explain the difference between organic and inorganic substances.
3. You can make a comparison between your own worldview and the evidence for evolution.

How old is the Earth?

How many years ago life originated on Earth?

Geological time scale

Earth came into being approximately   4,6 * 10^9  years ago

 

First single-celled organisms emerged approx. 3.8 * 10 ^ 9 years ago in the PRECAMBIUM

First multicellular organisms emerged approx. 670 * 10 ^ 6 years ago

First land plants: approx. 400 * 10 ^ 6 years ago in DEVOON

First vascular plants: approx. 350 * 10 ^ 6 years ago

First dinosaurs (reptiles): approx. 250 * 10 ^ 6 years ago in the MESOZOICUM (Triassic, Jurassic and Cretaceous)

Mass extinction dinosaurs: 65 * 10 ^ 6 years ago; start CENOZOICUM, mammals become dominant

First hominins: approx. 5 * 10 ^ 6 years ago

The red line in the graph indicates the oxygen tension in the Earth's atmosphere, where the x-axis should be read from right to left. The farther to the left, the longer ago. 1 Go on the x axis means 1 billion years ago.
Provide an explanation for the increase of the oxygen tension in stage 4 of the graph.

What are inorganic substances?

organic <-> inorganic

Inorganic substances are:

small and simply built

consist of only a few atomic types

main examples: O2, CO2, H2O, NO3, N2 etc.

Organic substances are:

more complicated in construction

consist at least of C, H and (usually) O atoms (often N and / or P and sometimes S and other types)

are produced by organisms

main examples: glucose, starch, amino acids, proteins, DNA / RNA, chlorophyll

What is organic/ inorganic

Water

DNA

Chlorophyll

Carbon Dioxide (CO2)

Glucose

Nitrogen (N2)

Protein

Nitrate

Oxygen (O2)

From lifeless to life: self-organization

inorganic substances

organic

substances

prokaryotic cell

energy

energy

Self-organization: creation of new units whereby new properties arise at a higher organizational level (emergent property).

Miller-Urey experiment

Creating organic matter (including sugars and amino acids) from a mixture of ammonia, methane, water and water vapor.

Electric discharges from lightning as a catalyst for chemical evolution.

From prokaryote to eukaryote:

endosymbiosis theory (Lynn Margulis)

another example of self-organization

Which two organelles have become part of eukaryotic cells according to the endosymbiosis theory?

Did you achieve these learning objectives?

- You can explain theories on how life could have originated on Earth.

- You can explain the difference between organic and inorganic substances.

- You can make a comparison between your own worldview and the evidence for evolution.

Work to be done

Assessment Questions Glencoe pg 441: Q 17-24 + 26-27 +29.  

Biozone 278 and 251.