Transcript Sep 11 - University of San Diego

I.
Characteristics of Biological Systems
D.
Regulation
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Metabolic processes controlled to maintain
homeostasis
Feedback regulation may be
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Negative (Ex: Glucose metabolism)
Positive (Ex: Blood clotting)
Fig 1.13
I.
Characteristics of Biological Systems
E.
Growth and Development
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F.
Increase in cell number, size, both
Uniform or local growth
Determinate or indeterminate growth
Development: Changes in structure and/or
function
Reproduction
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Asexual – No gametes
Sexual
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Genetic material from multiple individuals
Creates genetic variation – important for adaptation
and evolution
I.
Characteristics of Biological Systems
G. Evolutionary Adaptation
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Change over multiple generations
Involves natural selection
Peppered Moth
II.
Cellular Basis of Life
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All organisms composed of cells
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Organisms unicellular or multicellular
First observations of cork cells by Robert
Hooke (1665)
First observations of microorganisms by
Anton van Leeuwenhoek (~1665)
Cell Theory developed in 1838-1839 by
Schleiden and Schwann using inductive
reasoning
Later: Cells come from other cells, providing
basis for growth, reproduction, and repair
II.
Cellular Basis of Life
A.
Cell types
1.
Prokaryotic
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2.
Domains Archaea and Bacteria
No membrane-bounded organelles or membranebounded nucleus
DNA not separated from rest of cell
Most with tough exterior cell walls
Usually much smaller than eukaryotic cells
Eukaryotic
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Domain Eukarya (Animalia, Plantae, Fungi, Protists)
Membrane-bounded organelles
DNA separated from rest of cell as chromosomes in
nucleus
Some have cell walls (Plantae, Fungi)
Fig. 1.8
III.
Transmission of Heritable Information
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Basis for most species on earth is
DNA (Deoxyribonucleic Acid)
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Double-stranded backbone with four types of
nucleotide building blocks
Organized into functional units called genes
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Fundamental units of heredity
Transmission of genes  transmission of
traits
All known forms of life use same genetic code
Genetic complement of an organism =
genome
Fig. 1.11
IV. Diversity of Life
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About 1.8 million described species
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1,000,000+ insects
290,000+ plants
100,000+ fungi
52,000 vertebrates
Estimated total: 10-200 million
Classification system: taxonomy
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System developed by Carolus Linnaeus
Binomial nomenclature (Genus species)
Shared characteristics unite members of a
taxon (group)
Fig. 1.14
Fig. 1.15
IV. Diversity of Life
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Unity in diversity
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Similarities among distantly-related species
How can this
happen?
Fig. 1.16
V.
Evolution
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Concept underlies virtually all of
modern biology
Explains unity and diversity of life
Involves responses by species (not
organisms) to their environment
Charles Darwin (1859) – On the Origin
of Species by Means of Natural
Selection
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Synthesis of information from biology and
geology
V.
Evolution
A.
Descent with Modification
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B.
Species change from generation to
generation
Contemporary species arose from ancestral
species
Natural Selection
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Mechanism for evolutionary change
Fig. 1.20