121 Bio Lecture 2
A. How many species
a. 1.8 million are named/identified (thousands added per year most insects)
b. Absolute diversity (if we could name everything) estimated around 18 million
c. Estimated only 25% of bacteria known in a fecal sample
d. living species live =< 6% of land (mainly tropical forest (1 acre/minute
destruction)
d.i. Leading to extinction about 100 to 100x normal rate of extinction
d.ii. Leads to loss of genetic library
e. Argued reasons to conserve biological diversity
e.i. Moral/ethical approach humans are part of biosphere(every extinction
hurts humans somehow)
e.ii. Greed/self-interest - economic opportunities/ health/ pharmaceuticals/
tourism
e.iii. Free market approach resources reflect true value to society. Hard to tell
price/value of biodiversity.
B. Classifying life
a. Systematics studies the evolutionary and genetic relationships among organisms
a.i. Encompasses taxonomy branch of bio that deals with naming/classifying
of organism according to a formal scheme
a.ii. Construct tree of life
a.ii.1.
Linnaen hierarchy (Kingdom, phylum, class, order, family,
genius, species (king Phillip came over for great sex)
a.ii.2.
Reflects evolutionary history (phylogenetic tree graphical
representation of evolutionary history of speices based on
similarities and differences)
a.ii.3.
Scientists can use biochemistry, ecology, morphology
C. Molecular Phylogeny (used to determine evolutionary relationships)
a. Proteins
a.i. Made up of amino acids (differences and similarities in amino acids)
a.ii. Changes in amino acids can measure divergence
a.iii. Species that are more closely related have more similarities in their
molecules
a.iv. Which molecules?
a.iv.1.
Universally distributed (everyone has to have one)
a.iv.2.
Functionally homologous (do the same thing in every
organism)
a.iv.3.
Highly conserved regions (parts that are the same and can
be lined up)
a.iv.4.
Change at a rate that is commensurate with evolutionary
distance being measured (if measuring two things that are really
different molecule that changes slowly over time, if two really
related things- you want molecule that changes really fast)
a.iv.4.a. Cytochrome C slowly evolving enzyme inside
mitochondria (not good for closely related organisms
humans and chimps have same 104 amino acids of
cytochrome C)
a.iv.4.b. DNA sensitive (changes more rapidly)
D. Five Kingdoms
a. Based on cellular structure and mode of nutrition
a.i. Monera bacteria and cyanobacteria
a.i.1.
Live in diverse habitats
a.i.2.
Prokaryotes
a.i.3.
Unicellular
a.i.4.
Varied nutrition
a.ii. Protista - Protozoans
a.ii.1.
Eukaryotes
a.ii.2.
Varied nutritional efforts (absorptive, photosynthetic,
ingestive)
a.iii. Plantae plants
a.iii.1.
Photosynthesis (light energy into chemical energy)
a.iii.2.
Cellulose cell wall
a.iv. mold, Fungi mushroom, yeast
a.iv.1.
Decomposers (absorb nutrients from living or dead
organisms)
a.iv.2.
Chitin cell walls
a.v. Animalia animals
a.v.1.
Ingest particle food
a.v.2.
No cell wall
b. Eukaryotic vs Prokaryotic
b.i. Prokaryotic
b.i.1.
Asexual reproduction
b.i.2.
None/few membrane bound organelles
b.i.3.
Circular chromosomes
b.ii. Eukaryotes
b.ii.1.
Sexual and/or asexual reproduction
b.ii.2.
Membrane bound organelles
(mitochondria/chloroplasts/nucleus)
b.ii.3.
Linear chromosomes
E. 6 Kingdoms?
a. Biochelmical evidence
a.i. Sequenced rRNA separated monera into two groups
a.i.1.
Archea
a.i.1.a.
Live in extreme environments
(cold/hot/salty/basic/acidic/ pressure)
a.i.2.
Bacteria
F. Or 3 Domains?
a. Sequencing of rRNA led to discovery of 3 primary lineages
a.i. Created new taxonomy with 3 domains above kingdom
a.i.1.
Bacteria
a.i.2.
Archea
a.i.3.
Eukarea
G. Requirement for life
a. Metabolism (all chemical reactions in organism)
a.i. Breakdown of molecules energy release
a.ii. Buildup of molecules store energy
b. Reproduction - Continuation of form over time (generation to generation
b.i. copies need to be made of themselves
c. Genetics pass info from generation to generation (genes segments of DNA)
d. Evolution ability to change form and traits over time (from generation to
generation)
e. Growth
e.i. Growth of single organism
e.ii. Population growth
f. Adaptation
f.i. Must be able to respond to environmental changes
H. Lots of Solutions organismal diversity represents different combonations of characters
that solve the problem (different solutions to solving problems)
a. Common solutions
a.i. Replicated DNA
a.ii. Major metabolic pathways
a.iii. Genetic Code
b. Different Solutions (example to avoid stressful environment)
b.i. Bacteria/fungi spores
b.ii. Plants seeds/go dormant
b.iii. Animals hibernation/migration
b.iv. Protozoans cysts (little protective stages that are resistant to nasty
environment)
I. Nutrition (different organisms evolved different ways to satisfy nutritional requirements)
a. Autotrophy (self feeding) synthesize organic energy from non organic sources
(CO2, CH4)
a.i. Photosynthetic autotrophy energy source from light
a.ii. Chemosynthetic autotrophy energy from sulfer or CO2) break down
convalent bonds in H2
a.ii.1.
H2 + S H2S + energy
a.ii.2.
CO2 + 4H2 CH4 + 2H20 + energy
b. Heterotrophy (other feeding) obtain energy from organic sources
b.i. Predation
b.i.1.
Herbavory plant eating
b.i.2.
Carnivory meat eating
b.i.3.
Omnivory both
b.ii. Parasitism eating another organism without direct killing
b.iii. Detritivores utilize waste products as source of energy
c. Facultated Heterotrophy both (venus fly trap)
Good Exercise: Which of the kingdoms contain autotrophs and which contain heterotrophs and
which contain both?