Download Chapter 16

Where we’ve been
• To understand one aspect of biology we dig a bit
deeper to first learn the parts that make up the
whole
• To know evolution, you must know something
about genetics & heritable traits
…before that, you need to understand, cellular
reproduction, proteins, & DNA
…before that, how a cell works, how a
protein comes about, what makes up DNA
…membranes, organelles
…even down to molecules, atoms, etc.
Where we’re going
• Evolution & natural selection explains the vast natural
diversity of life… all the various organisms that we have
Organismal interactions
Population Dynamics
Communities
Biomes
Ecosystems
Diversity of Life
Hierarchy = organizational
levels
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Each level is nested
within the one above
Broad or less specific
More specific
Closely related species belong to the same genus, similar genera are included in a
family, etc…
Species that share the same structures, behaviors, etc, can interbreed and produce
fertile offspring.
• Grouped by shared
characters
(Evolutionary
relationships)
– Embryology
– Reproduction
strategies
– Symmetry (body plan)
– Morphology
– Feeding mode
– Etc…
Prokaryotes
•
•
•
•
•
Single cell
Very small
Cell wall
Lacks nucleus
Lacks membrane
bound organelles
• Binary fission
• Domains: Bacteria
and Archaea
Organizing prokaryotes
• Morphology
– E.g. bacilli, cocci, spirocheates
• Biochemistry & cell walls
– Using stains to determine structural differences
– Adaptations to environmental variations
• salinity, temperature, pH, O2 levels
• Modes of nutrition
– Heterotrophic (hetero = other, trophic = food or
feeding)
• Must consume organic molecules
– Autotrophic (self feeding)
• Photoautrophic can photosynthesize; get energy from sun
• Chemoautotrophic obtain energy from inorganic molecules
Bacteria
• Share prokaryotic
characteristics
• Causes some human
diseases
– Otherwise very
important
• Decomposers and
Nitrogen cyclers
Archaea
• Extremophiles
– Tolerant to extreme
environments
– Extreme halophiles
• High salt concentration
– Extreme thermophiles
• High and low temperature
– Methanogens
• Anaerobic environments
– Release methane
Eukaryotes
•
•
•
•
•
Protista, Fungi, Planatae, Animalia
Complex
>10x larger
DNA in nucleus
Cell membrane
– Some also have cell wall
• Membrane bound organelles
– specialization
Protista
• Very diverse
• Single celled & multicellular
• Autotrophs
– Plant-like
• Heterotrophs
– Animal-like protozoans
– Fungal-like
• Aquatic or moist environments
• Varies in modes of reproduction, locomotion, &
morphology
Diplomonads
– Spore forming
– Two nuclei
– Multiple flagella
– Usually anaerobic
– E.g. Giardia
• Intestinal parasite
• Contaminates streams
• Causes severe diarrhea
Trypanosoma
• Blood parasite
• Single encased
flagellum
• African tsetse fly
– Sleeping sickness
• Kissing bugs
– Chagas disease
Amoeboids
• Pseudopodia
– extensions of the cell
• Locomotion
• Feeding
• Various environments
• Various morphology
Ciliates
• Cilia to move and feed
– E.g. Paramecium,
Stentor, Vorticella
• Two nuclei types
– Macronucleus
• Everyday activities
– Micronuclei
• Sexual reproduction
Apicomplexans
• Parasites
• Apex structures for
penetrating host cells
• Lack cilia, flagella, or
pseudopods
• E.g. Plasmodium
– Malaria
– Enters and feeds on
red blood cells
– Spread by mosquitos
Dinoflagellates
• Two flagella in grooves
– Spinning flagellates
• Phytoplankton
– Photosynthesizing
aquatic species
– Red tides
• red pigments along with
chl a
– Some are toxic
• Shell fish accumulation
– Bioluminescence
Diatoms
• Phytoplankton
• Silica cell wall
– Glass-like
– Two halves like a petri
plate
• Mitotically divide the
halves
• Secretes the smaller
half
• Nucleus triggers
meiosis when too small
Multicellular protists
Phaeophyta
– Brown algae
• E.g. Macrocystis kelp
• Rhodophyta
– Red algae
• Chlorophyta
– Green algae
• E.g. Ulva, sea lettuce
• Lack true stems, leaves,
roots as in plants