BSCI124 Exam Guide 2 Lecture 8: Plant Diversity Taxonomic Hierarchy: how organisms are classified 1) Kingdom 2) Division 3) Class 4) Order 5) Family 6) Genus 7) Species ! Binomial naming: first name is genus, second name is species ! Biological species concept- a group of interbreeding populations; offspring are fertile ! Lamarckism- traits are acquired during the lifetime of an organism and passed to offspring; “use it or lose it” (individuals lost characteristics they don’t require) o Examples: the stretching of giraffes to reach leaves gives offspring longer necks ! Darwin’s Theory of Natural Selection: o Variation- members of a population have differences that are inheritable (won’t work with clones) o Overproduction- natural populations reproduce geometrically (populations produce more than can survive) o Competition- individuals compete for limited resources o Survival to reproduce- only the fittest survive and reproduce ! Artificial Selection: selective breeding as practiced by humans on domesticated plants & animals (ex. Dogs) ! Gradualism- evolution occurs as a slow and steady accumulation of changes in organisms ! Punctuated Equilibrium- there are long periods of no change followed by a rapid change Lecture 9: Evidence for Evolution and Plant Adaptations Types of Natural Selection: 1) Directional- one trait at the extreme of the range is favored over individuals with the average or opposite extreme of the trait 2) Stabilizing- the average trait is favored over the extreme traits 3) Disruptive- the extreme traits are favored over individuals with the average trait Evidence for Evolution: 1) Comparative analogy a. Homologous organs- similar in form in different organisms; share common origin but may have different functions (arm on human, horse, or dog) b. Analogous organs- have a similar look/function but do not share a common origin (wing on bird, wing on insect) c. Convergent evolution- unrelated organisms in a similar environment evolve similar adaptive structures d. Vestigial organs- organs/parts of organs that are non-functional (wisdom teeth) 2) Mimicry- harmless species may resemble a dangerous one (coral snake is venomous, milk snake is harmless but identical) 3) Developmental Biology (embryology)- early embryos (fetuses) of different species look very similar, share common features 4) Biogeography- each species has one place of origin; they spread out until they encounter a barrier (physical, environmental, ecological) 5) Molecular Biology- if we evolve from the same origin, then DNA should be very similar (people & apes) 6) Fossil Record- give evidence of extinct organisms from millions of years ago (the walking whale) Coevolution- long term evolutionary adjustment of one group of organisms to another; characteristics of one organism evolve in response to specific characteristics of another Symbiosis- ways in which 2 organisms can interact: 1) parasitism- interaction benefits one organism but hurts the other 2) commensualism- benefits one, doesn’t affect the other 3) mutualism- both organisms benefit Lecture 10: Viruses, Prokaryotes, & Fungi ! Viruses- non-living, cannot replicate/reproduce on its own, need a host to survive o Structure: protein coat (capsid) for protection and nucleic acid (DNA, RNA) for info on how to replicate o Virus is a cellular parasite- uses host to replicate o Cause diseases: HIV causes AIDS, SARS, influenza, norovirus causes stomach flu, HPV ! 6 Kingdoms of Living Organisms: o Archaebacteria- prokaryotic, ancient, live in harsh environments o Eubacteria- prokaryotic, have cell walls o Fungi- mold, mildew, mushrooms; have cell walls and roots o Protista- algae, slime molds, protozoa (cell walls but no cellulose) o Plantae- eukaryotes, photosynthesis o Animalia- eukaryotes, obtain food by ingestion ! Prokaryotic: do not have membrane bound organelles; eukaryotic: have membrane bound organelles !! Bacteria- prokaryotic: small, uni-cellular; have no internal organelles); haploid only o Structure: cell wall, chromosome, plasmids o Replication: asexual; no mitosisbinary fission o Feed: most are heterotrophic (obtain food from others); some are autotrophic (make their own food) o Pathogens: typhoid, tuberculosis, black plague, syphilis, gonorrhea o Control: disinfectants, antibiotics, low oxygen o Uses: yogurt, insulin, ! Endosymbiont Theory- chloroplasts and mitochondria are descendants of once free-living prokaryotes that were engulfed by larger cells; establishing a mutually beneficial relationship ! Fungi- eukaryotic; non-photosynthetic; have cell walls; haploid & diploid o Basidiomycota- form club0shaped basidia (mushrooms) o Zygomycota- reproduce by forming zygospores (bread molds) o Reproduction: sexual spores (meiosis); asexual spores (mitosis) o Feed: fungi secrete enzymes that break down molecules o Structure: most come in thread-like strands called hyphae; single strand are called yeasts o Commercial uses: yeast for fermentation alcohol, bread, cheese Lecture 11: Algae, Bryophytes & Ferns ! Algae- eukaryotes; mostly photosynthetic o Can be mircro or macroscopic; lack vascular tissues (no xylem or phloem) both sexual & asexual o Benefits of Algae:  Algae of base of aquatic food chain (photosynthetic)  Lichens: algae & fungi symbiosis  Serve as shelter  Provide oxygen 1) Diatoms- live in cool oceans, mostly unicellular a. important for aquatic food chains 2) Kelps/Brown Algae- rocky coasts in cold water; multicellular 3) Dinoflagellates- mainly unicellular, green/colorless, asexual reproduction a. Important in warm, tropical ocean food chains b. Responsible for red tide 4) Red Algae- oldest organisms on earth; act as food for marine species a. Structure: thin films to complex filaments b. Accessory pigments make it look red; can photosynthesize in deep water c. Commercial uses: ice cream, jelly, syrup 5) Green Algae- largest/most diverse; found in fresh water & land a. Important source of oxygen & food for aquatic organisms ! Origin of Land Plants: ancestor of land plants was green alga o Both have chlorophyll o Both have cellulose o Both have alternation of generations o Both form a cell plate ! Living on Land Issues & Solutions: a) Obtaining enough water roots evolved b) Preventing water loss cuticle evolved (waxy layer) c) Getting enough energy photosynthesis easier on land; tree grew taller