TA: Ronnie Steinitz rsteinit@ucsd.edu

BILD 3 Kurle 2014 - Lecture 11 11/18/14 This chapter is mostly memorization- Hooray, FLASHCARDS! Tree of life Five kingdom system 3 domains: o o o and - very successful (prokaryotes have more biomass than all plants and animals together) Evolutionary- first organisms Phylogenetic tree of Domains o (Eukaryotes at the top) o Each domain is mono-/para-/poly-phyletic (circle one) o We are constantly finding new species Relationships not known very well Eukarya Have cells contain true nuclei All multicellular orgs Some single celled Prokaryotic: Archaea and Bacteria Prokaryotes have: No -bounded organelles No envelope One circular chromosome Flagella for movement Pili helps them stick to other substrates Capsule sticky and helps adherence, or hide from hosts immune system No , but can transfer genetic information between cells, which keeps diversity high within prokaryotes

THIS IS NOT A STUDY GUIDE! Refer to lecture slides/readings for full content Relationships within different domains are poorly understood.

Examples of Bacteria Proteobacteria- o Ex. Rhizobium live in association with plant roots where they fix atmospheric nitrogen. Gram positive bacteria- o Ex. o Ex. Cyanobacteria- o This is likely where original (photosynthetic cells in plants) came from o In water, photosynthetic Spirochetes- o Pathogens causing Lyme disease and syphilis

Archaea First life forms were likely similar to archaea. Read more at the end of this handout! Extremophiles: o Extremophiles well represented in this group o Hard places to do research o philes- salty lakes Ex. Halobacterium o philes- hot springs thermovents (deep sea) Ex. sulfolobus o Methanogens in ice in Iceland , swamps, guts of animals Mostly anoxic (no oxygen) environments Archaea more similar to: Eukaryotes (share more recent common ancestor)

Autotroph/Heterotrph (circle one) = produces energy on their own (via solar or thermal energy) Autotroph/Heterotrph (circle one) = obtain energy by ingestion (cannot produce it on their own) Eukarya (protists) o Have eukaryotic cells with internal membrane bound structures (nucleus, mitochondria, chloroplasts) o Oldest found 2.1billion years ago o Diverse group of organisms (single cell, up to giant kelp) o Unicellular Eukaryotes o Largely unicellular, most aquatic o Phylogenetic tree- Archaea more closely related to eukaryotes than bacteria o Protists- o Not really plants but not really animals o Can move but not a lot o Can photosynthesize but not a lot All branches of this tree (besides bold, red ones) are Protists

4 Examples of Protists (Unicellular Eukarya) 1. a. Intestinal parasite that persists in water b. Feces mediated can get into water sources c. Can be prevented by Iodine tablets and water filters 2. Trypanosoma a. Cause in humans b. Vectored by tsetse flies c. In tropical Africa d. Causes vascular and lymphatic infection, can result in death e. Treatable with drugs 3. Dinoflagellates a. Cells reinforced with cellulose plates b. Twin flagella propel organism through water c. Blooms can cause Red Tides i. An accumulation of dinoflagellates which color the sea red ii. Some make neurotoxin that doesnt hurt mollusks iii. But it can hurt everything else iv. Influx of nutrients cause a bloom, causes red tide- high concentration of neurotoxin in mollusks, can make mollusks poisonous to humans d. Some are bioluminescent i. Release light as a product of a chemical reaction inside them ii. Remember, we talked about the evolution of bioluminescence? iii. Make light when disturbed to confuse predator

4. Diatoms a. Unicellular algae with a cell wall composed of silica b. Freshwater (rivers and lakes) and marine (oceanic) c. Use of silica makes them easy/difficult (circle one) to consume d. VERY diverse Eukarya Algae (Protists, focus on Algae) Multicellular algae include brown, red and green algae (Giant kelp is algae) Red and green algae belong to Archaeplastida, which likely gave rise to plants Alternation of generation (gametophyte (n) and sporophyte (2n) and multicellular embryos dependent on maternal plant) life cycle where they alternate physical form depending on which phase they are in. [Figure with cycle in the end of the worksheet] Three Groups of Algae Brown Algae Ex. Kelp, Seaweed Exclusively marine In the same supergroup as diatoms, dinoflag., and apicomplexans But NOT red and green algae Ex. Giant Kelp; Macrocystis Red Algae Ex. Porphyra used in sushi Mostly marine, can occur in great depths can absorb blue and green light Many can exhibit alternation of generations Many are filamentous Green Algae Ex. Cholerpa Many can exhibit alternation of generations Chloroplasts similar in structure to those found in land plants Marine, freshwater and terrestrial EXTREMELY INVASIVE!!! Eukarya Land Plants Colonization of land transformed the terrestrial environments of Earth 500mya small plants 370mya first forests Plants provide us with oxygen and food, and have many other positive functions Land Colonization: Advantages Challenges / Disadvantages

Abundant CO2 Relative scarcity of water

Abundant Light (Autotrophs) Lack of structural support

Nutrients more plentiful Herbivores eventually

Initially, no herbivores

Most living plants are Angiosperms (Flowering plants) Plant synapomorphies: (things that are derived, novel, and define land plants) 1. Alternation of generation (gametophyte (n) and sporophyte (2n) and multicellular embryos dependent on maternal plant) a. Embryos retained within parent plant- nutrients to help growth b. Charophytes lack alternation of generation c. Because land plants evolved this trait independent of the algae 2. Haploid spores produced in sporangia resist desiccation 3. Multicellular gametangia (to protect, give nutrients). a. Gametangia: A gametangium (plural: gametangia) is an organ or cell in which gametes are produced that is found in many multicellular protists, algae, fungi, and the gametophytes of plants. A gametangium is a haploid structure and formation of gametes does not involve meiosis. 4. Apical meristem- localized regions of cell division that allow roots and shoots to penetrate soil and to extend into the air (roots growing down, branches growing up)

Vascular plants- most plants on land (origin ~420mya) -Water conducting cells xylem and phloem contain lignin (a rigid polymer) roots absorb water and nutrients leaves increase surface area of plant body for photosynthesis Seedless vascular plants: ferns, horsetails gametophyte is reduced but independent and photosynthetic often occur in moist environments include club moss Forests today are dominated by vascular plants with seeds, but 360mya seedless trees dominated Seed plants Diversified in carboniferous period- 360mya Seed: an embryo + some food in a protective coat Seeds are detachable, mobile, capable of prolonged dormancy Can withstand harsh physical conditions Pollen: haploid stage male gametophyte within sporophyte-derived wall Carried long distances by wind or water (or animal). No reliance on water for fertilization (like algae) Gymnosperms (one of the seeded groups) Sporophyte is dominant stage with tiny gametophyte inside male and female cones Gametophyte protected and nutritionally supported by sporophyte Naked seeds- not enclosed within an ovary, on modified leaves that form cones

1. Gingko trees - living fossil 2. Cycas revolute 3. Gnetophytes 4. Conifers; Ex: a. Sequoias b. Pines c. Fir Include worlds oldest, tallest trees High elevation, grow slowly (one tree is 5000yo) Seed Plants: Angiosperms Other group of seed plants- Sporophyte is dominant phase flowing plants gametophyte- male and female, found in the flower itself depend on the sporophyte for nutrition Flowers: a specialized structure for sexual reproduction Stamens produce pollen (male) Carpel produces ovules (female) Fertilized ovules become seeds inside fruit Pollination Answers: 1. Cones / fruits 2. Mesozoic / Cenozoic 3. Wind / animal Angiosperms the largest group of plants today Monocots and dicots DNA studies suggest that monocots are a clade, monophyletic, but dicots are polyphyletic. Flowering- monocots Dicots- veggies, pees, zucchini

"Nothing in biology makes sense except in

the light of evolution." Theodosius Dobzhansky, Geneticist FIRST LIFE FORMS: So what were the first living things and when did they appear? Studies of genetic material indicate that a living group of single-celled organisms called Archaea may share many features with early life on Earth. Many Archaea now live in hot springs, deep-sea vents, saline water, and other harsh environments. If the first organisms resembled modern Archaea, they also may have lived in such places, but direct evidence for early life is controversial because it is difficult to distinguish between complex inorganic structures and simple biological ones in the geologic record. The oldest evidence for life may be 3.5-billion-year-old sedimentary structures from Australia that resemble stromatolites. Stromatolites are created today by living mats of microorganisms (mostly cyanobacteria, or blue-green algae). These primitive organisms trap thin layers of sediment with their sticky filaments and grow upward to get light for photosynthesis. Modern-day examples of stromatolites can be found in waters off Australia, the Bahamas, and Belize. [source: http://paleobiology.si.edu/geotime/main/htmlversion/archean3.html]