Lecture Exam 2

Animal protists

- "Protozoans" - Unicellular and heterotrophic - Distinguished by organelles of motion (flagella, cilia, pseudopodia, or axopodia). - Structurally are similar but not closely related molecularly. - Change form during life cycle, so some have more than 1 host. - Some require vectors (insects) to move them from host to host. - Often follow fecal/oral life cycle

Amoebozoans

- Amoeboid protozoans - Amoeba, Chaos, Entamoeba - Most closely related to true fungi and animals, based on molecular evidence. - Have pseudopodia for movement and feeding - Entabamoeba histolytica causes amoebic dysentery. Fecal/oral cycle. Infects 10% of world population.

Unikonta

- Amoebozoans, slime molds, nucleariids, fungi, choanoflagellates, animals.

Paramecium

- Appear multicellular, though are unicellular. - Cilia move food into mouth and move entire cell. - Oral groove functions as mouth - Food vacuoles package food for digestion - Anal pore expels wastes - Contractile vacuole expels excess water - Conjugation - Method of sexual reproduction involved in gametic life cycle. Two fuse and exchange micronuclei.

Plasmodium

- Causes malaria, the most fatal disease caused by protozoans. - Vector: Female Anopheles mosquito. - Parasite makes mosquitoes feed several times per night, and it makes humans more appetizing to mosquitoes. - Malaria is fatal if not treated. Infects 40% of world's population in tropics. - Can reduce blood flow to brain, leading to coma and death. - Prevention: Antimalarial medications, insecticides, bed nets, remove standing water. Life cycle: 1. Sporozoites form in salivary glands of mosquito. 2. Sporozoites infect humans when mosquito bites human. Move to liver. 3. Merozoites form in the liver. 4. Merozoites are released from the liver and infect RBCs 5. Merozoites are released from RBCs 48 - 72 hours later 6. Either re-infect RBCs or get ingested by mosquito 7. If ingested by mosquito, forms gametes 8. Gametes form sporozoites, completing Plasmodium life cycle.

Specialized meristems

- Cells that divide to increase length and diameter of plant body (stem cells) - Apical: Increase length of plant body at shoot and root tips (primary growth) - Lateral: Increase diameter of woody plant body (primary growth) - Vascular cambium: Lateral meristem in woody plants. Increases diameter during secondary growth.

Charophytes

- Chara - Considered most closely related to green plants (stalk, stem, branches) - Share characteristics with both green algae and plants. - Distinguished by oogonia

Sporic life cycle

- Characterized by alternation of generations. There are two multicellular forms in the life cycle that alternate generations - gametophyte and sporophyte. Gametophyte - Haploid; produces gametes by mitosis. Gametes fuse to form zygote, which develops into sporophyte. Sporophyte - Diploid; produces haploid spores by meiosis. Spores develop into haploid gametophytes. - Characteristic of all plants and most algae. Gametes (n) Zygote (2n) Mitosis Sporophyte (2n) Sporangia (2n) Meiosis of sporangia Spores (n) Mitosis Gametophyte (n) Mitosis Gametes (n)

Green algae

- Chlamydomonas, Closterium, Volvox, Spirogyra, and Ulva, charophytes - Major component of fresh water and marine phytoplankton

Phylum Lycophyta

- Club mosses (Lycopodium, Selaginella) - Seedless - Vascular (xylem and phloem) - Most primitive living vascular plants - Ancestors were dominant plant in carboniferous forests approx. 425 mya. Contribute to coal deposits. - Sporophyte dominant - True roots - Microphylls and sporophylls - 2 life cycle patterns: homosporous and heterosporous - For heterosporous, flagellated sperm swim to eggs, forming zygote. Zygote forms sporophyte.

Ovule

- Composed of integument, megasporangium, and megaspore - Integument encloses megasporangium and megaspore - Micropyle - Opening into ovule between integument ends that allows pollen tube to direct sperm into ovule. *See pic*

Chromalveolata

- Derived from secondary endosymbiosis with red algae. - Includes dinoflagellates, apicomplexa, ciliates, oomycetes, diatoms, brown algae groups. - All characterized by membrane-enclosed sacs inside cell membrane with unknown function. Do All Other Colors Die Black?

Gametic life cycle

- Diploid phase is dominant. - Gametes (egg and sperm) are only haploid phase. Gametes form zygote, which forms the multicellular diploid body. - Most advanced life cycle. Characteristic of animals. Gametes (n) Fertilization Zygote (2n) Multicellular diploid body cells (2n) Meiosis Gametes (n)

7 adaptations of land plants for terrestrial environments

- Don't occur in Charophyta 1. Vascular tissue 2. Specialized meristems 3. Multicellular haploid and diploid alternation of generations in life cycle 4. Leaves with stomata and waxy cuticle 5. Sporophylls 6. True roots 7. Secondary compounds

Protists

- Eukaryotic and mostly unicellular. - Not true animals, plants, or fungi. - Supergroups are based on molecular and morphological evidence.

Trypanosoma

- Excavata - Flagellated - Kinetoplastid - Single, large mitochondrion with organized mass of DNA. - Mitochondria cause disease - Causes African sleeping sickness in humans and cattle. - Natural reservoirs: Lion, hyena, antelope. - Vector: Tse tse fly - Trypanosomes release neurotoxins into blood, which eventually affects the CNS. Causes sleep disorders, paralysis, and death. - Alters surface proteins (antigens) to evade immune response. 1/3 of its genome produces surface antigens.

Euglena

- Excavata - Green with red eye spot - Derived from secondary endosymbiosis with green algae. - Exhibits plant and animal characteristics: Plant: 1. Photosynthetic in light. Red eyespot directs Euglena to or away from light. Has chlorophyll a and b like green algae, plants, and cercozoans. Animal: 1. Heterotrophic with 2 flagella for locomotion. Flagella have crystalline structure next to 9 +2 microtubules. 2. Ingests prey by phagocytosis, so it can survive in the dark. - Reproduces by mitosis (asexual).

Giardia

- Excavata - Heart-shaped cell with 2 nuclei and several flagella - Cysts transmitted to host by fecal contaminated water, food, or contact - Causes hiker's diarrhea - Adapted to live in animal's digestive tract, so mostly anaerobic metabolism - Mitosomes - Modified mitochondria with non-functional electron transport chain (because anaerobic, so no oxygen).

Excavata

- Flagellates - Giardia, Euglena, Trypanosoma - Characterization: 1. Flagella 2. Feeding groove along 1 side of cell body 3. Bilateral symmetry

Seed

- Forms from fertilized ovule - Contains embryo (diploid sporophyte) and stored nutrients for embryo - Seed coat forms from integument to protects embryo from UV, desiccation, herbivory. Allows seeds to remain dormant when environment is unfavorable. *Study Pic*

Charophyta

- Genus: Chara - Green algae - Multicellular group thought to be closest living, photosynthetic relative of land plants, based on chloroplasts, nuclear DNA, morphology, and biochemistry. - Share characteristics with both land plants and green algae (chlorophyll a and b, photosynthetic, starch is storage product, and cellulose external cell walls). - Exhibits 3 characteristics that also occur in land plants but not in green algae (cellulose-synthesizing enzymes, peroxisome enzymes that prevent break down of carbon compounds during photorespiration, and cell plate that supports new wall that forms between 2 cells during cell division)

Plasmodium (slime mold)

- Growth form of slime mold - Large, diploid, multinucleate cell without cross walls. - Feeds on bacteria, yeast, fungal spores, and decaying matter - Reproduces sexually when environment becomes unfavorable. Forms stalked sporangia and haploid spores. ---Spores form gametes. Gametes form zygote. Zygote forms diploid, multinucleate plasmodium. Plasmodium resumes feeding.

Phylum Pteridospermophyta

- Gymnosperm - Seed ferns - Medullosa - Extinct - Oldest true gymnosperm group (350 myo) - Resemble ferns but produced seeds, not spores

Zygotic life cycle

- Haploid phase is dominant. Zygote is the only diploid phase in the life cycle. - Zygote divides by meiosis to form haploid cells and gametes. - Characteristic of fungi and spirogyra (green algae). - Most primitive life cycle. Gametes (n) Zygote (2n) Meiosis Haploid cells (n) - Most of life cycle Mitosis Gametes (n)

Equisetum

- Horsetail - Calamites are extinct - True roots, stems, and microphylls - Green stems are main photosynthetic organ - Stems have joints with microphylls - Stems are hollow for gas exchange - Stems have silica - Sporophylls form strobilus at tip of stem, producing homosporous spores that form gametophyte.

Slime mold protists

- Included with amoebas but not directly related to any animal or fungus group. - Animal-like because it moves through environment. - Fungus-like because it produces sporangia and spores.

Ciliates

- Includes Paramecium, Stentor - Lost chloroplasts - Characterized by macronuclei (for metabolism) and micronuclei (for sexual reproduction). - Cells without micronuclei can only reproduce asexually.

Vascular tissue adaptation

- Land plants have vascular tissue that conducts water and nutrients throughout the plant. - Xylem - Conducts water and minerals up from roots to leaves - Phloem - Conducts sugars and other nutrients from leaves throughout plant

Leaves with stomata and waxy cuticle

- Leaves capture sun energy for photosynthesis - Stomata: Pores through epidermis and cuticle that open and close to allow gas exchange and control water loss. - Waxy cuticle: Protects exposed surfaces from dehydration and herbivory. - Leaves are microphylls or megaphylls

Phylum Hepatophyta

- Liverworts (Marchantia) - Seedless - Non-vascular - Gametophyte dominant - Simpler than mosses; no stomata. Thus, probably older than mosses (475 myo) - Gametophytes also reproduce asexually by gemma cups, which produce new gametophytes.

Pollen grain

- Male gametophyte with sperm. - Develops from microspore. - Meiosis in microsporangium forms microspore - Wind or animals move pollen with sperm to egg (not flagellated) - Cycads and Ginkgo are only ones with flagellated sperm.

Phylum Bryophyta

- Mosses (Polytrichium and Sphagnum) - Non-vascular; water and minerals absorbed across surface. - Seedless - First land plants; dominant during 1st 1 million years of plant evolution approx. 475 mya - Evolved in wet habitats are remain dependent on water to survive. - Thin external cell walls limit size of plant - Photosynthetic, though no true leaves - Stomata - Rhizoids - root-like; anchor plant but don't absorb water. - Produce flagellated sperm that swim to egg. - Gametophyte dominant; sporophyte reduced.

Seed plants

- Most familiar, widespread, and evolutionarily successful plant group. - Archaeosperma was first seed approx. 275 mya. Seeds with megaspores inside protective branches.

Land plants

- Multicellular, photosynthetic. - 290,000 living species.

Slime molds

- No direct relationships to any other groups - Not related to fungi - Physarum - Plasmodial slime mold.

Progymnosperms

- Not true gymnosperm because produced spores, not seeds - Genus Archaeopteris - Extinct - Lived around 380 mya - Large, woody trees with fern-like leaves that did not produce seeds (produced spores). - Hypothesized to be transitional form between seedless and seed plants.

Rhynia major (Aglaophyton)

- Oldest fossil vascular plant. 450 myo. - Branching, photosynthetic stems without true leaves or roots. - Seedless (produces spores in sporangia) - Cylinder of vascular conducting tissue in stem.

Plant protists

- Photosynthetic - Probably derived by secondary endosymbiosis (from red or green algae). - Distinguished by photosynthetic pigments, storage products, external cell wall.

Psilotum

- Phylum Pteridophyta - Whisk fern. Oldest living vascular plant group (approx 400 myo)

Ferns

- Polypodium - True roots, stems, and leaves (fronds) - Sporophyte dominant - Homosporous sporangia clustered into sorus on underside of frond. - Spores form tiny gametophytes that produce both antheridia and archaegonia. Flagellated sperm fertilizes egg. Zygote forms sporophyte (diploid).

Red algae

- Porphyra and Polysiphonia - Most abundant algae in tropical oceans - Red photosynthetic pigments - Chlorophyll a and d *Don't have chlorophyll b or c. - Used commercially for: 1. Agar (for growing microorganisms) 2. Moisture retainers for creams 3. Suspending agent in chocolate milk and puddings 4. Wrap for sushi (Porphyra gametophyte called "nori")

Microphylls

- Primitive leaf. Only 1 vein off of stem (one vascular trace). - Photosynthetic - Only living species with microphylls: Equisetum, Lycopodium, Selaginella, Psilotum

Homosporous sporophylls

- Produced by Lycopodium, ferns, Equisetum. Sporangia produce 1 type of spores. - Spores form gametophyte (n) with both antheridia and archaegonia - Sporophylls produce 1 sporangium type, 1 spore type, 1 gametophyte produces both antheridia and archaegonia (which lead to both sperm and egg).

Heterosporous sporophylls

- Produced by Selaginella and higher plants - Produce 2 different sporangia that produce heterosporous spores. - Microsporangia form microspores, which form male gametophyte (n) in antheridia by mitosis. - Megasporangia form megaspores, which form female gametophyte (n) that forms egg in archaegonium by mitosis. - Sporophylls produce 2 different sporangia type, 2 different spore types, and 2 different gametophytes (megasporangia and microsporangia)

Phylum Pteridophyta

- Psilotum, ferns, Equisetum - Seedless, vascular - Sporophyte dominant - 12,000+ living species, mostly ferns

Rhizaria

- Radiolarans, foraminiferans, cercozoans - Axopodia (cytoplasmic extensions) for feeding and movement. -

Archaeplastida

- Red algae, green algae, charophytes, green plants - All photosynthetic

Secondary endosymbiosis

- Red and green algae were engulfed by other heterotrophic eukaryotes, forming photosynthetic protists. 1. Between heterotrophic eukaryote and red algae - Forms dinoflagellates, apicomplexans, diatoms, and brown algae. 2. Between heterotrophic eukaryote and green algae - Forms euglenas and chlorarachniophytes. 1. Primary endosymbiosis - Heterotrophic eukaryote or prokaryote engulfed cyanobacterium, forming a chloroplast. Branched into red and green algae: A. Red algae (photosynthetic eukaryotic organism) was engulfed by heterotrophic eukaryote. Branched into Dinoglafellates, Apicomplexans, and Stramenopiles. B. Green algae (photosynthetic eukaryotic organism) was engulfed by heterotrophic eukaryote. Branched into Euglenids and Chlorarachniophytes.

Fungus protists

- Resemble higher fungi - Some parasitic - Characterized by hyphae filaments and sporangia with spores

Brown algae

- Sargassum, Fucus, and Macrocystis (kelp) - Mostly marine - Multicellular. Largest and most complex algae group. - Derived from red algae - Brown photosynthetic pigments like dinoflagellates and diatoms (chlorophyll a and c) - Characterized by thallus (plant-like growth form). Includes holdfast, stipe, blades, and air bladders. - Sexual reproduction

Angiosperms

- Seeds are contained in flowers. - Phylum Anthophyta - Dominant plant group today (250,000 species)

Sargassum life cycle

- Sexual reproduction - Brown algae - Sporic life cycle - 2 multicellular heteromorphic stages in life cycle: Sporophyte (diploid) dominant and gametophyte (haploid) reduced. 1. Sporophyte forms sporangia 2. Sporangia form haploid spores by meiosis 3. Haploid spores form haploid male and female gametophytes 4. Gametophytes form gametes by mitosis 5. Flagellated sperm swim to egg in female gametophyte. 6. Sperm fertilizes egg, forming zygote. 7. Zygote forms new diploid sporophyte by mitosis.

Sporophylls

- Specialized leaves that form sporangia. - Organized into strobili (cones in conifers) or flowers.

Volvox

- Supergroup Archaeplastida - Type of Green algae - Colonial algae - Whirling sphere of flagellated cells that enclose new colonies

Closterium

- Supergroup Archaeplastida - Type of Green algae - Elongate - Unicellular with two chloroplasts and a central nucleus

Ulva

- Supergroup Archaeplastida - Type of Green algae - Sea lettuce - Multicellular - Isomorphic stages in life cycle. Sporophyte and gametophyte look identical, so no dominant or reduced. - Sporic life cycle

Spirogyra

- Supergroup Archaeplastida - Type of Green algae - Unbranched, multicellular filaments - Spirally-arranged chloroplasts - Sexual reproduction involves conjugation between filaments of different individuals. Zygotic life cycle.

Chlamydomonas

- Supergroup Archaeplastida - Type of Green algae - Unicellular, flagellated, haploid - Cup-shaped chloroplast with chlorophyll a and b (similar to plants) - Eyespot in chloroplast for light detection - Starch is storage product (like in plants) - Cellulose in external cell wall (like in plants) - Reproduces sexually in response to stress (scarce nutrients). Zygotic life cycle.

Apicomplexa

- Supergroup Chromalveolata - Intracellular parasites in animals. - Microtubules at apical end pierce and infect host cells. - Includes Plasmodium

Dinoflagellates

- Supergroup Chromalveolata - Includes Ceratium (which looks like a star, and stars sparkle like bioluminescence). - Part of marine and fresh water phytoplankton. - Have brown photosynthetic pigments similar to diatoms and brown algae (chlorophyll a and c). - Have 2 unequal flagella to rotate the body. One is in groove that extends behind them, and one is in groove around center of cell. - Some are bioluminescent, which may startle or attract predators (attract to dinoflagellate predators). - Some cause algal blooms (red tide) in warm temperatures that have excess nutrients. Algal blooms produce neurotoxins that accumulate in fish and shellfish, which are harmful to other fish and humans.

Cercozoans

- Supergroup Rhizaria - Chlorarachniophytes. - Ex: Paulinella - Evolved recently by secondary endosymbiosis - Green photosynthetic pigments (similar to green algae and euglena) - Has cyanobacterium and green algae endosymbionts 4 membranes around the chloroplast reflect endosymbiosis in action. 1. 2 inner membranes were cell membrane and outer LPS membrane of cyanobacterium. 2. 3rd membrane was the membrane around the green algae that was engulfed by a heterotroph 3. 4th membrane was from the heterotroph's food vacuole membrane

Foraminiferans

- Supergroup Rhizaria - Common in fossil record back to Cambrian - Calcium carbonate shell - Shell deposits formed White Cliffs of Dover (in England)

Radiolarans

- Supergroup Rhizaria - Common in fossil record back to Precambrian era. Silica shells.

Megaphylls

- True leaves. Produced by all land plants, other than Equisetum, Lycopodium, Selaginella, Psilotum. - Have branching vein system in leaves.

Alternation of generations

- Two stages of plant life cycle - Multicellular haploid and diploid - Haploid gametophye produces gametes by mitosis. a. Male produces sperm in antheridium, which moves via flagella, wind, or animals to egg b. Female produces large non-motile egg in archaegonium. Forms zygote when fertilized by sperm. - Zygote forms embryo, which forms multicellular diploid sporophyte. - Diploid sporophyte produces sporangia, which produce haploid spores by meiosis. Spores form haploid gametophytes.

Diatoms

- Unicellular - Derived from red algae - Have brown photosynthetic pigments similar to brown algae and dinoflagellates (chlorophyll a and c) - Composed of two pieces of silica cell walls that fit like box and lid - Classified by wall shape, ornamentation, and symmetry (central or pinnate) - Mostly asexual reproduction in which each new cell gets cytoplasm and 1 silica wall that regenerates the other silica wall. - Their shells accumulate in aquatic ecosystems to form diatomaceous earth deposits that are used as detergents, polishes, filters, insulators, and deodorizers. - Abundant in fossil record and many living forms.

Gymnosperms

- Vascular seed plants - Seeds are contained in cones - Includes: progymnosperms, seed ferns, cycads, Ginkgo, gnetophytes, and conifers.

Gametophyte dominant alternation of generations stages

1. Gametophyte (haploid) produces sperm in antheridia and egg in archaegonium. 2. Flagellated sperm fertilizes egg in archaegonium, forming zygote. 3. Zygote forms small, short-lived sporophyte (diploid) 4. Sporophyte capsule contains sporangium. Spores (haploid) form by meiosis in sporangium. 5. Spores released through openings in operculum of capsule when capsule dries. Peristome teeth shake out spores in wind. 6. Haploid spores form haploid protonema filaments that form haploid gametophytes.

Two alternation of generations patterns

1. Isomorphic 2. Heteromorphic

5 gymnosperm phyla

1. Pteridospermophyta 2. Cycadophyta 3. Ginkgophyta 4. Gnetophyta 5. Coniferophyta

Seedless plant reproductive cycle

1. Spores (n) 2. Gametophyte (n). Divides by mitosis to form gametes (n). 3. Gametes combine to form Zygote (2n). 4. Sporophyte (2n) 5. Strobili 6. Sporophylls 7. Sporangia (2n). Divide by meiosis to form spores (n).

Seed plant evolutionary trends

1. Sporic life cycle - Sporophyte dominant, with gametophyte in structures on sporophyte (not free living). 2. Pollen grain - Develops from microspore 3. Ovule 4. Seed forms from fertilized ovule

3 Patterns of Life Cycles in Sexually Reproducing Organisms

1. Zygotic 2. Gametic 3. Sporic

Mitosis

2n --> 2n; n --> n

Meiosis

2n --> n

True roots

Absorb water and minerals from soil. Anchor and stabilize plant to allow plant to grow taller.

Sporophyte dominant, gametophyte reduced

All land plants, other than mosses and liverworts

Holdfast

Anchors brown algae to surfaces, though not a root (doesn't allow for absorption).

How are land plants classified?

By presence or absence of vascular tissue.

Flowers

Cluster of modified sporophylls. Found on flowering plants.

Strobilus

Cluster of sporophylls. Found on Lycopodium, Selaginella, gymnosperms.

Secondary compounds

Ex: Flavonoids Functions: 1. Deter herbivores 2. Protect from UV light 3. Attract pollinators.

Air bladders

Floats that keep blades of brown algae near surface.

Megasporangium

Forms megaspore by meiosis. Megaspore forms female gametophyte with egg (by mitosis). - Megasporangium is enclosed in ovule.

Stentor

Funnel-shaped ciliate with cilia around anterior end.

Lepidodendron

Large trees of phylum Lycophyta that are more than 40 meters tall and 2 meters wide.

Dominant

Larger form and longer lived generation. Main form of life cycle.

Blade

Leaf-like structure that functions for photosynthesis in brown algae.

Choanoflagellates

Living group considered to be most closely related to Kingdom Animalia.

Nucleariids

Living group considered to be most closely related to Kingdom Fungi.

Gametophyte dominant, sporophyte reduced

Mosses and liverworts

Non-vascular plants

No vascular tissue to conduct water and nutrients throughout plant. Ex: Bryophyte group - Non-vascular, seedless, all lack true roots and true leaves. Includes mosses and liverworts.

5 supergroups

Original Kingdom Protista is arranged into 5 supergroups in Domain Eukarya. Based on molecular characteristics (DNA sequencing) and morphological evidence. Excavata Chromalveolata Rhizaria Archaeplastida Unikonta - All of the categories under the 5 supergroups are protists, except for land plants, fungi, and animals.

Eukaryotic life cycles

Sexually reproducing organisms have 2 stages in their life cycle - haploid and diploid. Both phases can be unicellular or multicellular. Haploid - n. 1 copy of each chromosome. - Haploid spores or gametes form by meiosis. Diploid - 2n. 2 copies of each chromosome. - Gametes fuse to form zygote (1st diploid cell). - Diploid phase divides by meiosis to form haploid spores or gametes. - 3 patterns of life cycles in sexually reproducing organisms.

Reduced

Smaller and shorter lived form of life cycle.

Isomorphic alteration of generations

Sporophyte and gametophyte look identical. Less common than heteromorphic. Ex: Ulva

Heteromorphic alteration of generations

Sporophyte and gametophyte look very different. Two types: 1. Gametophyte dominant, sporophyte reduced. Ex: Mosses, Porphyra (red algae). 2. Sporophyte dominant, gametophyte reduced. Ex: Most plants, Laminaria.

Stipe

Stem-like structure that supports thallus in brown algae.

Vascular plants

Vascular tissue conducts water and nutrients throughout plant. 1. Fern group - Vascular, true leaves and roots, seedless, produce spores. Lycopodium, Selaginella, ferns, Psilotum, Equisetum. 2. Gymnosperms and angiosperms - Seed-producing - Most advanced plant group. 90% of land plants. - Gymnosperms - Produce seeds in cones. Cycads, Gingko, gnetophytes, conifers - Angiosperms - Produce seeds in fruits. All flowering plants. Monocots and dicots.

Oomycetes

Water molds. Resemble fungi due to convergence. Many are parasites. - Phytophthora - Cause of Irish potato famine in 1845 - Saprolegnia - Fish fungus (mold)