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, O 2 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