Biological
Principles
1. The Organization
of Life
a. Origin of Life
i. Abiotic Production of Organic Molecules
1. Hypotheses on Origin of Macromolecules
2. Making Organic Compounds: The Stanley Miller Experiment & Others
Chemosynthesis: The use of inorganic substances such as carbon dioxide
to make carbohydrates from the energy released by chemical reactions.
ii. Macromolecules to Living Cells
1. Prebionts: Nonliving structures that evolved into the first living cells
2. Coacervates: Colloidal aggregation containing a mixture of organic compounds.
The formation of coacervates in the primeval soup was a step towards the
development of cells.
Organic molecules surrounded by a film of water molecules
Selectively absorb materials from surrounding water
Incorporate them into their structure
Not a random arrangement of molecules
3. Microsphere
Organic molecules surrounded by a double membrane
Can be formed from Proteinoids, when placed in boiling water & cooled.
iii. Microspheres = Protocells!!
iv. Earliest Evidence of Life
1. Stromatolites
2. Hypotheses
for where Life Originated
1. Vent Hypothesis: Chemosynthetic, external source of energy for earliest
(anaerobic) autotrophs were chemical reactions (not sun).
2. Tidal Pool Hypothesis: Hot tidal pools of seawater concentrated chemicals
and provided energy for origin of amino acids and DNA.
3. Panspermia: Life originated on Mars, and rode to Earth in meteorites.
Image
source: http://library.thinkquest.org
3. Classification
of Organisms: Typological (base on the type specimen)
a. The Species Concept
i. Biological
ii. Paleontological
b. Basis for classification = Evolution
i. Hierarchy of classification
1. Domain> Kingdom> Phylum (or Division)> Class> Order> Family> Genus (pl.
Genera)> Species
ii. Classification of humans
1. Domain: Eucarya
2. Kingdom: Animalia
3. Phylum: Chordata(Plants use Division instead of Phylum)
4. Class: Mammalia
5. Order: Primates
6. Family: Hominidae
7. Genus: Homo
8. Species: Homo sapiens
iii. Domains:
1. Bacteria: heterotrophic, cyanobacteria (stromatolites)
2. Archaea: halophiles, thermophiles
3. Eucarya
a. Kingdom Protista
b. Kingdom Fungi
c. Kingdom Animalia
d. Kingdom Plantae
iv. Taxonomy: the study of the composition and relationships of those groups.
Taxon individual group (pl. taxa)
v. Species: group of individuals that can interbreed.
4. The basic
dichotomy of life
a. Cell: is a membrane-bounded module with a variety of distinct features,
including structures in which certain chemical reaction take place.
b. Prokaryotic Cells (Domains Bacteria and Archaea
Cells of the most primitive organisms have cells that lack a nucleus.
Monerans (bacteria and related organisms) are prokaryotes.
Prokaryotes also lack other membrane-bound internal structures.
c. Eukaryotic Cells
All organisms, other than monerans, have cells with nuclei.
Cells with nuclei = eukaryotic cells, and the organisms made of such cells
are eukaryotes.Eukaryotic cells have membrane-bound internal structures
(organelles) in addition to the nucleus.Endosymbiosis: for the origin of
the eukaryotic
5. Characteristics
of Animals
a. Features Used to Classify the Animal Kingdom
1. Grade of organization of cells
a. Cellular Level
b. Tissue Level
c. Organ Level
2. Body symmetry
a. Bilateral
b. Radial or spherical
c. Asymmetrical
3. Number of skin cell layers in early development
a. Primitive simplest animals lack differentiated dermal layers
b. More advanced forms
c. Ectoderm (outer skin)
d. Mesoderm (middle skin)
e. Endoderm (inner skin)
4. Presence or Absence of Coelom (internal fluid-filled
cavity in the body, See table 2.1)
a. Acoelomates
b. Pseudoacolemates
c. Eucoelomates
d. Lophophorates
e. Schizocoels = protostromes (first mouth)
f. Enterocoels = deuterostomes (second mouth)
5. Presence or absence of segmentation: Divisions of the body
6. Characteristics
of Plants
a. The Organization of Life (Plant Kingdom)
i. Eukaryotic organisms
ii. Manufacture their own food
1. photosynthesis
2. autotrophs (self-feeding)
b. Division of Plants
i. Presence or absence of vascular tissue and Habitat
1. Algae: aquatic (marine and fresh water), lack vascular tissue
2. Tracheophytes (have vascular tissue = true land plants)
3. Bryophytes (mosses and liverworts) do not have vascular tissue (live
on land)
7. The theory
of organic evolution: Evolution is the central, unifying theory of modern
biology.
Darwin and
the Origin of Species by Natural Selection:
1.- Life is old: Was not created but evolved from previously existing organisms
2.- Life started with simple organisms and became more complex with time
3.- Natural Selection is the force that drives evolution
a. Natural Selection
b. The Genetic Basis of Evolution: Mutations
c. The level at which evolution takes place
i. Species (interbreeding)
ii. Population (genetic variation)
iii. Individuals (single)
d. The Mechanisms of Evolution:
i. Variation
ii. Natural Selection
iii. Isolation: Geographic distribution of organisms
e. Modes of speciation
i. Phyletic evolution: Gradualism, slow change; evol. horses -MICROEVOLUTION
ii. Punctuated equilibrium: Rapid change
f. Extinctions
i. Causes of extinction
1. Physical:
a. local environmental change
b. climate change
c. extraterrestrial causes
2. Biological:
a. increased predation
b. new predator or disease
c. humans
g. Patterns of Evolution
i. Divergence: new species (speciation)
ii. Convergence: groups develop similar-looking characteristics
1. Homologous (structure evolves from similar ancestral feature)
2. Analogous structures (similar functions, dissimilar origins)
iii. Parallel evolution: unrelated lineages undergo similar evolutionary
changes through time.
iv. Speciation: Adaptive radiation and mass extinction. Speciation is caused
by reproductive barriers
1. Physical reproductive barriers:
a. mountain range
b. boundary between ocean layers
2. Biological reproductive barriers:
a. differences in mating behavior
b. incompatibility of egg and sperm
c. differences in reproductive timing
v. Radiation: rapid origin of many new species from a single ancestral
group
8. Environments
of Life: Some Concepts
a. Habitat: Setting on or close to the Earth’s surface that are inhabited
by life.
i. Aquatic
1. Marine (oceans and seas
2. Freshwater (lakes, rivers, and streams)
ii. Terrestrial
b. Ecology: the study of the factors that govern the distribution and abundance
of organisms in natural environments
c. Niche: relations between a given species and it environment
d. Life Habitat: the way a species lives within its niche.
i. Limiting factors: physical and chemical conditions that restrict every
species to its niche.
e. Population: group of individuals that belong to a single species
f. Community: populations of several species living together in a habit.
Some species feed on others
i. Producers: the foundation of the system, photosynthesizing organisms
or bacteria that harness the energy of chemical reactions
ii. Consumers: herbivores which feed on producers
iii. Carnivores, feed on other consumers
g. Ecosystem: Organisms of an ecological community and the physical environment
they occupy. Come in all sizes
i. Fauna: The animals and protozoans (Protists) of an ecosystem
ii. Flora: Plants and plantlike Protists of an ecosystem
iii. Biota: Flora and fauna living together
iv. Food Chain: sequence of species from producer to top carnivore
v. Diversity: designate the number of species that live together within
a community
vi. Opportunistic species: species that specialize in invading newly vacated
habitats, e.g, land cleared by fire, or shore areas formed along rivers
that change course at flood stage.
h. Biogeography: Distributions and abundances of organisms on a broad geographic
scale.
i. Realms: a primary marine or terrestrial biogeographic division of the
earth's surface
1. Terrestrial
2. Marine
a. Plankton: organisms that drift in water
i. Phytoplankton
ii. Zooplankton
b. Nekton: Animals that move through the water primarily by swimming
c. Pelagic: plankton and nekton in the open ocean
d. Benthos: immobile and mobile organisms that populate the seafloor.
e. Benthic herbivores graze on plantlike forms like algae
i. Suspension feeders: strain phytoplankton and plan debris from the water.
ii. Deposit feeders: Consume sediment and digest organic mater mixed in
with mineral grains.
Source: <http://www.bigelow.org/virtual/bath_sub1.html#margin>