Chapter 1 - Introduction-The Biosphere and the Evolution of Life

INTRODUCTORY BIOLOGY

By

HOANG ANH HOANG, Ph.D.

Department of Biotechnology,

Faculty of Chemical Engineering, HCMUT

How the subject evaluated?

• 2 credits (10 weeks)

• Score:

- 30% mid-term exam (constructed-response test)

- 20% seminar

- 50% final exam (multiple-choice test)

• Seminar:

- One group: 3-4 persons (6-7 groups)

- Topics: to be given at week 5

References

1. Carol Leth Stone (2004) The Basics of Biology, Greenwood Press, USA

2. Harvey Lodish (2008) Molecular Cell Biology, 6th

edition, W. H. Freeman Publisher (2008)

3. Gerard J. Tortora et al. (2013) MICROBIOLOGY - An Introduction, 11th edition, Pearson Publisher, USA.

4. Other sources….

Outline of the subject

• Part 1: The Biosphere and The Evolution of Life

• Part 2: Cell biology

• Part 3: Microbiology

• Part 4: Genetics and Molecular biology

• Part 5: Applications of biotechnology

Chapter 1: The Biosphere and The Evolution of Life

I. The Biosphere• Nonliving part v.s. Living part?

• The nonliving parts of Earth: the hydrosphere (water), the atmosphere (air), and the lithosphere (rock).

• The living part is the biosphere (3 domains)

Phylogenetic tree

- Bacteria, Archaea (Prokaryota): not “true” nucleus

- Eukaryota: “true” nucleus

• Bacteria

- Negative gram bacteria (Ex: E. coli)

- Positive gram bacteria (Ex: L. monocytogenes)

• Bacteria:

- Shapes and arrangements

• Bacterial distributions

- soil

- water

- waste

- acid or base condition

- hot or cold temperature

- ….

• Archaea

- are prokaryote but they can survive at very adverse conditions: very hot, very acidic, very high salty,…

- genome structure different from that of bacteria…

Phylogenetic tree

The hot springs, Yellowstone

National Park, USA

SulfolobusHalophiles

Methanobacterium

• Eukaryota

- Fungi

- Some microalgae

- Animals

- Plants

• Fungi:

- unicellular microorganisms: yeasts and molds

Bread yeast

Penicillium chrysogenum

Orange infected by moldsSaccharomyces cerevisiae

• Fungi:

- multicellular fungi: mushrooms

• Some microalgae

Animals & Plants

Virus?• Nonliving or living parts of the Earth??!!

• A virus is a small infectious agent that replicates only inside the living cells of other organisms

HIV virus Ebola virus

• Virus types

- Animal virus

- Plant virus

- Bacterial virus

- Archaea virus

• DNA or RNA genome (DNA or RNA virus)

• All virus are harmful ?

Virus shapes

• Bacterial virus (bacteriophage)

Infection cycle

II. Links within the Living World• The Chemistry of Organisms

- Like all matter in the universe, organisms are made up of chemicals.

Ex.: Saccharomyces cerevisiae has formula:

C3921H6365O2070N597P40S6

Saccharomyces cerevisiae

• Atomic component

• Macromolecules

- Proteins 50%

- Nucleic acids 15%

- Carbohydrates 15%

- Lipids 10%

• Chemical bonds

Elements of Life

Food chain

• In terms of food, organisms fall into three main categories—producers, consumers, and decomposers.

• Producers: plants and micro-organisms

• Consumer: animals

• Decomposer: Micro-organisms

• No organism is a link in just one food chain.

Biological control

• Predator–Prey interaction

- Natural

- Selective

- Safe

Cycles of Matter and Energy

• When organisms die, decomposers, such as bacteria and molds, use the chemical matter and energy they contain for food.

• The energy used at each step in a food chain is not recycled.

Cycle of matters

• Carbon Cycle

Cycle of matters

• Nitrogen Cycle

• Energy Pyramid

The energy transferred at each level is considerably less than at the previous level

Changing population

• Four things determine population size: birth rate, death rate, immigration rate, and emigration rate

• Competition, Commensalism, Predator–Prey Interactions,…

III. EVOLUTION OF LIFE

Charles Darwin

A Summary of Darwin’s Theory

• All life evolved from one simple kind of organism.

• Each species arose from another species that preceded it in time.

• Evolutionary changes were gradual and of long duration.

• Each species originated in a single geographic location.

• The greater the similarity between two groups of organisms, the closer their relationship

• Extinction of old forms (species, etc.) is a consequence of the production of new forms or of environmental change.

• Once a species or other group has become extinct, it never reappears.

• Evolution continues today in generally the same manner as during preceding geologic eras.

Evolution by natural selection

• Every species has a potential to increase in number by the production of offspring.

• The offspring are genetically variable, so they have variable abilities to use resources.

• The resources needed for survival in each environment are finite.

• Each environment selects offspring that are best able to survive.

ANTIBIOTIC-RESISTANT BACTERIA

• Nearly 100% of bacterial infections caused by Staphylococcus were susceptible to penicillin in 1952. By 1982, less than 10% were susceptible.

Artificial (directed) evolution