Evolution
• Basic
themes of biology include
evolution, information transfer,
and energy for life
• Genetic change in a population over time
Information Transfer
• Genetic information is transferred:
– Within cells
– Within organisms
– Among organisms
– From one generation to another
What characteristics distinguish living
organisms from nonliving things?
What is life?
Energy for Life
• Energy flows
- from the Sun to Earth
- from producers to consumers
All living organisms are
composed of cells
Cell structure:
• Plasma membrane
– Surrounds and protects cell
– Separates cell from environment
• DNA
– Codes genetic instructions
• Organelles
– Internal structures for special functions
1
Two Types of Cells
• Prokaryotic cells
– Bacteria and archaea
– Single celled organisms
– No membrane-bound organelles
• Eukaryotic cells
Organisms Grow and Develop
• Biological growth
– Increases size and/or number of cells
• Development
– Changes that take place during an
organism’s lifetime
– Organelles enclosed by membranes
– Nucleus contains DNA
Organisms Regulate Their
Metabolic Processes
• Metabolism
– All the chemical activities of the organism
Organisms Respond to Stimuli
• Stimuli
– Physical or chemical changes in the
internal or external environment
• Homeostasis
– Mechanisms regulate and balance the
internal environment
Organisms Reproduce
• Asexual reproduction
– Low genetic variability
What are the hierarchical levels of
biological organization?
• Sexual reproduction
– High genetic variability
2
The
Hierarchy of
Biological
Organization
What is the importance of
information transfer to living
organisms?
Ecological
Hierarchy
DNA
• Transmits
information from
one generation to
the next
• Codes for proteins
Evolution:
The Unifying Concept of Biology
• Theory of Evolution
– Explains changes in populations over time
Information is Transmitted
• Chemical and electrical signals
– Proteins
– Hormones
– Neurons (nerve cells)
– Neurotransmitters
Organizing the Study of Life
• Systematics
– Study of organisms and their evolutionary
relationships
• Taxonomy
– Science of naming and classifying
organisms
• Species
– Populations capable of breeding with one
another
3
Taxonomic Classification is
Hierarchical
Taxonomic Classification
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Three
Domains: Bacteria
Archaea
Eukarya
Light
energy
Energy Flow
Six Kingdoms:
Heat
Bacteria Archaea
Protista
Plantae
Animalia
Fungi
Food
Consumer
(caterpillar)
Consumer
(robin)
Producer
(plant)
Tree of Life
Plant litter,
wastes
Common
ancestor of
all organisms
Soil
Fig. 1-9, p. 12
Autotrophs
• Producers (autotrophs)
– Make their own food
– Transform light energy to chemical energy
through photosynthesis
• Photosynthesis
CO2 + water + light → sugars + oxygen
Dead
bodies
Decomposers
(bacteria, fungi)
Fig. 1-13, p. 14
Heterotrophs
• Consumers (heterotrophs) use energy stored
by producers through cellular respiration
sugars + oxygen → CO2 + water + energy
• Decomposers (heterotrophs) break down
wastes and dead organisms
4
NUTRITION
Chemicals:
Nutrients
Some used as
raw materials
OTHER
ACTIVITIES
• Homeostasis
• Movement of
materials in and
out of cells
• Growth and
development
• Reproduction
SYNTHESIS
Manufacture of
needed materials
and structures
organic compounds
Some used as
fuel
CELLULAR
RESPIRATION
Biological process
of breaking down
molecules
• Carbohydrates
– Sugars & starches
– Energy
• Lipids
– Fats (animal), oils (plant)
– Energy, cell membrane
– Hormones
Energy
Fig. 1-12, p. 14
Chemicals: organic compounds
• Proteins
– Made of amino acids
– Multiple functions
– Enzymes – speed up chemical reactions
• Nucleic acids
– DNA, RNA
– Make proteins
Organelles
Cells & Organelles
• “Little organs”
• Nucleus
– Largest
– Contains DNA
• Rough ER
– Contains
ribosomes
– Make proteins
• Smooth ER
– Makes lipids
Mitochondria
• Lysosome
– Digestive enzymes
– Molecules, dead organelles
• Produce ATP = energy
• Contain DNA
• 100-1000s per cell
• Majority of organelles
inherited from mother
5
Plasma Membrane
• Cell membrane (edge)
• Special lipid = phospholipid
– Keeps organelles inside
Genetics
• Cells
– Units of life
• DNA
– Deoxyribonucleic acid
– Molecule of genes
(Units of heredity)
• Genome
– All DNA in a cell
DNA
• 4 bases (nucleotides)
–A
–C
–G
–T
Gene
• Segment of DNA
• Determines amino acid sequence
of a protein
• Protein Æ physical characteristics
– Phenotypes
• Sequence of bases
• Genes are DNA segments
• Genes Æ proteins
• RNA
– Helps to make proteins
Nucleotide
Chromosomes
• Single unit of DNA
– Deoxyribose sugar
– Phosphate group
– Nitrogenous base
• 4 nitrogenous bases
•
•
•
•
Threads of DNA
46 in human cells
3 billion nucleotides
~21,000 genes
– Adenine (A), Guanine (G)
– Cytosine (C), Thymine (T)
– A, G = Purines
– C, T = Pyrimidines
6
Mitosis
Mitosis?
Mitosis: division of cells that results
in daughter cells with the same
the genetic information that the
original cell had.
• Division of somatic (body) cells
• Growth and repair!!!
46
46
46
Diploid 2n
Diploid 2 n
Mitosis
• Replicated chromosomes align at equator
• 2 new cells form
Meiosis
Meiosis: division of cells that results
in daughter cells with one-half of
the genetic information that the
original cell had.
23
46
Diploid 2n
23
23
23
Haploid n
7