Lecture 2-Evolution, Info and Energy

Evolution and Life on Earth

Lecture 2

Friday, March 15, 13

Topics Covered in this Module • Life on Earth• Evolution: The Core Theme in Biology

Major Objectives of this Module • Identify evolution as the core theme and unifying

concept in biology.• Distinguish between the biological and the

common meanings of the word evolution.• Explain how evolution has led to both the unity

and the diversity of life forms.


Life on Earth

A cuttlefish senses its surroundings through its w-shaped pupil.

The eye sends information to the brain, which quickly relays messages to particular pigment cells in the skin. The muscles pull on the pigment cells so they expand, and the cuttlefish instantly resembles what its eye sees. Evolution is behind the formation of these traits.


Figure 2: Cells, the basic units of life.

All cells have cell membranes, ribosomes, and DNA. The DNA is packaged differently in eukaryotic and prokaryotic cells, but it has the same basic structure and function.


• Sources of Genetic Variation

• Mutations

• Gene Recombination

DNA is a great unifier for all of life

• Biological Evolution

• Process that results in heritable changes


Figure 5: Biological classification.

The classification system in use today relies on the hierarchical system developed by Linneaus, with the addition of several categories, including the domain - the most inclusive category. This schematic shows the classification of the polar bear (Ursus maritimus).


Natural Selection

Natural Selection is the process whereby organisms better adapted to their environment tend to survive and produce offspring.


Evolution explains the unity of life.

Figure 9: Homologies.

The forelimbs of a variety of mammals use the same bones, slightly modified, for different purposes. The genes that code for the bones are also very similar. These similarities that arise from sharing a common ancestor are called homologies. The forelimbs in mammals are considered homologous structures. Homology is the phenomonon of homologies among different organisms.

It all comes down to DNAFriday, March 15, 13




Three-Domain tree of Life

Comparing sequences of a conserved ribosomal gene in archaea with the same gene in other prokaryotes and eukaryotes, scientists found that archaea were so different from eukaryotes and even from other prokaryotes that they deserved an entirely new classification category.


Evolutionary thinking applies to all levels of biological

organization.


Biological Information and Interactions


Topics Covered in this Module • Organisms Are Centers of Information

Transfer• Responding to Information

Major Objectives of this Module • Describe how living things inherit genetic

information.• Explain how cells receive, process, and

respond to signals from their environment.


What about animals/humans?


Central Dogma of Molecular Biology


• Information is stored

• Genes are the functional units of information

• Information is interpreted and transmitted

• Information goes from “virtual” to “real”


Double strand DNA


Storing and interpreting DNA instructions.

One DNA molecule contains many genes. The DNA consists of two strands that are joined by base pairing between complementary nitrogenous bases. Each strand of DNA can therefore act as a template, or pattern, either for completing the other DNA strand or for producing mRNA, a mobile copy of the information in the base sequence. The mRNA then serves as the template for assembling a specific sequence of amino acids.


General Transfer


Special Transfer


Responding to Information

Sense, transmit, process and answer back at all levels of biological organization:

Chemical ReactionCell Signaling


Energy and Matter

Lecture 3



Topics Covered in this Module • Matter and Energy in the Earth System

Major Objectives of this Module • Define energy and matter.• Explain how energy and matter interact on multiple

levels of biological organization from cells to organisms to ecosystems to the Earth system.

• Explain how organisms use energy and matter to form living structures and perform life processes.


• What is Matter?

• What is Energy?



Thermodynamics

First Law: Energy is not created or destroyed. It can be just transformed

Second Law: Every transformation of Energy has a lost as Heat. This Heat increases the entropy of

the universeFriday, March 15, 13

Different Kind of Energy







Figure 2-56 Molecular Biology of the Cell (© Garland Science 2008)

COUPLED REACTIONS


Exergonic and Endergonic Reactions



• Coupled Reactions• Activated Carriers


Figure 2-69 Molecular Biology of the Cell (© Garland Science 2008)


ATP is the most used Act. Carrier


ANOTHER ENERGETIC CARRIER


ANOTHER ENERGETIC CARRIER


Documents

Lecture 2-Evolution, Info and Energy