Lecture 11 Classification
1. Introduction to Survey of Life
- The change in coverage - through the years
GRE's, texts and lectures.
a) major events; move to land, origin of sex.
b) major importance to us: vertebrates,
but also insects, fungi = why should you care.
c) How organisms meet major challenges
-internal challenges
communication, waste, digestion, differentiation = intra and intercellular
issues.
- external challenges
resource competition,
predators,
dispersal, mating,
avoid unfavorable circumstances
2. New concepts of Classification.
c. biological definition - Distribution curve for variation
e. rule of priority for species names
3. Higher Categories
a.Rule of Usage: how many kingdoms.
b.Basis: phyletic-- monophyly, polyphyly
phenetic
cladistic
4. Cladistics
compared to other systems
homology - current difficulties in usage
Shared Derived Characters= synaptomorphy
5. Problems
- Equivalent trees and number of possibilities
- brushpile evolution
= close taxonomic distances- no discrimination
- gene shifts between branches
- continued differences in classification: what is a plant?
- Traditional names vs "new" ones
different content = different name.
Lecture 12 The Diversity of Life
1. Kingdoms and "domains"
Aristotle-Linneus to 1850 = two kingdoms; Animalia, Plantae(fungi, algae)
1850- Ernst Haeckel - Protista
recognized monera as odd
1937- Charlton, coined terms procaryotes, eucaryotes
1956- four kingdoms (procaryota, Proctista
1959-Whittaker - 5 kingdoms - fungi
1990- 6 kingdoms Woese - Archaebacteria, Eubacteria
Protista (include algae)
shift from morphology to structure to biochemistry
Viruses???
2. Diversity through time.
increase with periodic catastrophies, periodic major
invasions of new realms.
3. Diversity in absolute numbers.
a) numbers
b) estimates of % known or described species
c) tropical richness.
5. How Evolution Works (reminder)
- brushpile evolution - try all possibilities on entering a clade.
- winners and loosers/ greater vs lesser potential; 1st bird = odd reptile
- Multiple solutions to evolutionary problems
skeleton: hydrostatic, external, internal
each solution has limitations, advantages.
Lecture 13 Domain Bacteria
www.ucmp.berkeley.edu/archaea/archaea.html
trishul.sci.gu.edu.au/~bharat/courses/ss13bmm/archaea.html
1. The new category "Domain" = based on cladistics.
2. Morphology vs chemical pathways.
3. The Three domains.
a) Procaryotic vs Eucaryotic
nuclear membrane, organelles, cytoskeletonn
b) changes within the procaryotes.
ribosomal RNA - work of Carl Woese
4. The new Picture -
"Brushpile evolution"
Bacterial brushpile - eucaryotes a side branch as far as
biochemical evolution is concerned
Bacterial reproduction
haploid ring DNA
transformation, transduction, conjugation
exchange of fragments of info
Total DNA sequence of Bacteria
probability of genetic exchanges across distant
species = intertwining branches of evolution.
5. Archaea
extremophiles, hot, cold and normal temps
varied/ energy sources
cell membrane, cell wall specializations
some similarities to Eucaryotes
some interesting industrial applications
insights into origin of life
6. Eubacteria.
three shapes., cocci, bacillus, spirochaetes
taxonomic shift from morphology to molecular level
gram positive vs gram negative = staining of cell wall;
based on amount of peptidoglycan
gram negative - little peptidoglycan, harder to attack as antibiotics target the peptidoglycan.
ecologic importance
nitrogen fixation soil bacteria
fermentation
disease
mutation rate and resistance
bacteria as unsuspected causes of disease
new diseases.
Viruses
biology - obligate parasites
origin - fragments?
gene transfer - importance
role in oceans
role in disease.
Lecture 14 Protista
1. Classification see book
eucaryotes
large and varied group: plant, animal, fungi
motile, non-motile
one cell - multi cell
defined by absence of traits
poor taxonomy
Brushpile pattern
basis of taxonomic groups.
algae - pigment systems
protozoa - locomotion, covering
slime molds - cell types.
2. Origin of Diploidy - sex
why?
variation
parasitic protection
purge of bad genes
variation in reproductive cycles; all patterns
isomorphic, diplontic, haplontic
isogamous, anisogamous
3. Origin of the Eucaryotic cell
steps - reasons for each
Giardia - an intermediate
4. Variations among Protists -how they deal with the world
5. Important Protists
Malaria - resistence
algae - oxygen supply
6. Drinking water
water purification and pollution
water treatment
small vs large towns
Lecture 15 Fungi and early plants
1. General Characteristics - absorbtive heterotrophs
absorbtive nutrition,
cell wall of chitin
spore reproduction
2. Structure
hypha(e) mycelium - no cell division
most decomposers, some parasitic, predatory
3. Reproduction
mating types vs sex.
haploid adults
2 types grow together, form dikaryon (2 nuclei in cell) fuse - meiosis
diploid organnism = nucleus only
4. Evolution
come on land- after plants
1 group aquatic - flagellated spore
on land - airborne spore, dispersion and survive unfavorable conditions
sex prior to spore formation - creates variety
5. Symbiosis
with algae = lichens
with higher plants = root absorption
important in plant dominance-
diseases; ringworm, toenail rot, valley fever,
frog deaths
fungi in hospitals.
Plants
1/ Origins of multicellularity
cell differentiation 3400 million years ago life arises
1000 "" multicellular life
more complicated than filiaments
volvox- a model form 1000cells, differentiation.
how to study;see mutants- what they do
3 genes cause initial differentiation
restrict division to germ cells
basics: turning off or on dna in some cells.
2. Algae -
Caulerpa - one cell - microtubules
Kelp - holfast, stem, leaves, floats, reproductive cells.
Classification: if use chloroplast, chlorophyl a dn b, starch as storage, then green algae are plants. If use embryo, then land plants = plantae, green algae = proctista.
Plantae =
starch, plastid structure, cellulose walls
reproduction = multicellular gametophyte and sporophyte
1st land plants = Non tracheophytes
Liverworts
cuticle - h20 retention
diplobiontic - alt of generations
haploid spores - dessication resistent
reproduce in h20
no special support system, no "leaves'- whole plant can photosynthesize,
roots = support, not water supply
NO STOMATA
desert moss and dessication.
Lecture 16 Land Plant Evolution
Mosses - other non-tracheophytes
add stomata -
value for - h20 retention
- sequestering photosynthetic cells
- regulation of transpiration -
function - open and close - turgor pressure
based on ion movement, light.
Tracheophytes: Ferns,
problem of competition for light - need to grow in size.
development of
- growth system
- support system
- vascular system - between roots (h20) and leaves -
development of "trachea" = ribbed cells in xylem
complex system
xylem - dead cells, hollow, sieves at ends
support cells - h20 goes up
mechanism - root pressure
- capillary action
- cohesion and evaporation
phloem - living, sugar goes down
based on concentration gradient of sugars,
cytoplasmic flow, sieve tubes, conversion of starch to sugar to vary osmotic pressure.
Cambium = growth tissue which forms xylem and phloem
organization: bundles - to higher forms, zones.
Additional problem - getting h20 into roots = osmotic pump action plus fungi hyphae
Fern reproduction: gametophyte reduced, but still H20 dependent.
Higher plants Gymnosperms and Angiosperms
most of our larger plants today.
Have in common
-development of secondary growth - diameter = organization of xylem, phloem and cambium
-reduction of gametophyte generation to "parasite" within the sporophyte
-development of seeds - dispersal phase
gymnosperms - "evergreens"
change from motile sperm to pollen and pollen tubes
use of wind for pollination
Angiosperms - flowering plants
use of pollen, but with flowers = attractants to facilitate pollination
life cycle - the complexity of pollination and embryo development.
fruit - attractants to facilitate dispersal and growth.
2 major groups
Monocots
Dicots
Lecture 17 Plant responses to environment -
Plants need to respond to environment
issues of timing, environmental conditions (day length, temperature, moisture, disturbances etc.
Mechansim of response = chemical = hormones
Light, temp, moisure
when should a seed germinate??
20 types of dormacy.
after cold, after h20 available, after abraision
after chemical digestion, light conditions.
How should a plant grow??
stem vs leaves
Methods of response
growth direction - phototropism, geotropism
elongation vs leaves
flowering, ripening - life cycle
stress
Hormone activity.
How to tell if a hormone is present
eliminate source, use chemical stimulation
dose effects - different resonses at different doses
opposite effects - turn on turn off
pleitropic effects - different effect on different systems
basic hormones - Auxin
Giberrelin
Kinetins
phytochrome
Lecture 18 Plant adaptations to environment.
major problems of a sessile, edible organism: dispersal, protection, survive bad conditions
1 Dispersal
gravity - wind, fruits, burrs,
big seed vs small seed tradeoffs: energy, waste, etc.
2. Reproduction
clones - aspen
self fertilization
if sex; how to avoid waste
flowers, pollinators
timing, who to attract?
3. Predators how to protect self
regeneration
poisons, galls,
find bodyguards
4. Competition
use poisons -
get resources - h20
5. Bad conditions
annual - fast response to good conditions, dormacy
perennial - cut losses, cactus, be deciduous, store h20,
Hairy - for dew, avoid insects
fire" - how to survive it; as seed, as root, thick bark
6. Things nature can't deal with
invasive diseases = dutch elm, chestnut blight
new conditions = water table lowering, too much water
Lecture 19 Animals - Overview
1. Difficulty
the time from eucaryotic cell to multicellularity.
cell differentiation and regulation of DNA information.
2. Major groups B identified and illustrated.\
3. The Cambrian explosion.
Lecture 20 B Animals B relationships.
2. The "Traditional" morphologic classification
Based on Embryology - development (Haeckel)
simple to complex
- Volvox like
- Diploblasts; 2 layers, radially symmetrical
- Triplobalsts; bilaterally symmetrical
Acoelomata ; solid placozoa, roundworms
Pseudoceolomata; cavity outside mesoderm
coelomata cavity inside mesoderm
Protostomes
deuterostomes
3. The "New" phylogeny = based on 8s ribosomal DNA
keeps deuterostome, protostome split and diploblasts
breaks up Protostomes into
Lophotrochozoa - filtering tentacle
Ecdysozoa - moulting animals
places acoelomates in Lophotrochozoa
splits Pseudocoelomates into both groups.
Note: poor resolution of relationships (brushpile)
Implication: acoelomate and pseudocoelomates are simplified and derived, not primitive
4. The "New" Evolutionary - Developmental Biology
same or similar genes in dissimilar organisms
indicates - common ancestor with the gene
" - change in gene function
the ancestor - simple or complicated.??
Lecture 21 B Major Problems faced by Animals
1. Size increase
skeletons
circulation
respiration.
Metamorphosis?
2. Issues of Being Sessile vs motile
protection
sponges
reproduction
food procurement
why develop a head and sense organs.
corals -
3. Major environmental issues
water salt vs fresh vs land. B requirements for living on land.
Dessication
Waste
Extreme environments. B heat, cold, dry.
Solutions B
Sensing the environment quickly B sense organs and what they can do.
Lecture 22. Arthropods B basis of success.
Arthropods million species maybe 20 million!!
Charcteristics
derived from annelids= bilateral, triploblastic, segmented
Exoskeleton = major advance.= protection against injury and physiologic stress
requires - joint appendages,
moulting for growth
respiratory system = three types results in open circulation - haemocoel
Crustacea - crabs, isopods, etc.
biramous appendages, most aquatic, some terrestrial
Cheliceriforms - spiders
Insects -
Major groups,
spiracles
origin of flying
extreme specialization, speciation
Social Insects
basis = chromosome numbers and relatedness
body types
communication - chemicals and hormones.
How to deal with insects B biological control.
Lecture 23 Origin and early evolution of Chordates-Vertebrates
1, Deuterostomes
reminder of characters
Echinoderms 13,000 secies
Deuterostome bilateral larvae - secondarily radial adults
pentaradiate
2.. Origin from sessile filter feeders = primitive deuterostomes- like echinoderms
how?? - tunicate largae, amphioxus
use of living relics as indicators
why?? - dispersal efficiency
somatic vs visceral organism
vertebrate body plan = gills (flow counterflow)
dorsal notochord, nerve cord.
blood flow direction
way of life:
filter feeder to bottom sucker = develop gills jawless.
3.. Becoming a better "fish"
1st verts = agnatha; armored, no fins, no jaws
swimming: paired appendages
loss of armor
better skeletal support to somatic organism
two types of bone/ext, int.
jaws: new food possibilities
major radiations.- classification of "fish"
Lecture 24. Amphibia and Reptilia
1. Coming onto land.
who?? - sarcopterygian, crossopterygian type fish
characteristics - fleshy fins,
lungs adapted to swamp habitat.
origin of lungs - story of increasing sophistication of structure.
why?? - two just so stories - both to stay in water!
2. Amphibians
perfection of land adaptation
loose weight
better limbs
girdle development
decrease head size
survivors get smaller - eat worms. (why?- competition from reptiles)
3. The Joys of Reptiles
a. Transition from Amphibian to Reptile - the reptilian egg
- What is needed.
already in amphibia
loss of metamorphosis, lay eggs on land.
new
internal fertilization
extra-embryonic membranes.- a truely new development
b. The reptilian radiation.
aquatic, aerial, terrestrial
our change of view - dumb to social, warm and smart.
Lecture 25 Birds and Mammals
1.. Origin of Birds.
archaeopteryx
original function of feathers
why fly? two stories
how to lighten body: lungs, urine, skeletal fusion
bird evolution and the K-T Boundary
modern birds - social, active, intelligent, etc. as models for dinosaurs?
2. Mammals
a. What is a mammal??
Hair, warm blood?? - no
reproduction?? - monotremes.
b. Primitive mammals and mammal origins
active carnivores = basis of all changes.
limbs and position
toes
teeth(roots, regionalization, sets)
lower jaw simplification
ribs-lungs - diaphragm
2ndary palate
c. The taxonomic mess for cladistics - what to do with "reptile" ancestors of mammals?
d. Marsupials and Placentals = loss of external egg.
advantages?
e.. The Placental pattern of development - odd in that something added at the beginning of development, not at end.
f. Mammalian radiations
air, land, water
g. Primates
arboreal - allows diurnal
diurnal allows stererscopic vision, memory
memory = brain devt.
arboreal - one young - greater dependency - learning vs genes.
social structure - based on eating fruit!!!
coming down to ground = devt of savannahs.
brain development - history of size increase
correlated with??
view of history of human origins as due to a lucky set of circumstances, not preordained.