BSC3016 Eukaryotic Diversity

Bryophyte diversity

"Bryophyte" is an informal term to refer to the three phyla of non-vascular land plants: liverworts, hornworts, mosses "Bryophyta" is the formal PHYLUM name for mosses Bryophytes are small, herbaceous, non-woody plants Bryophytes are not a monophyletic group (their relationships to each other & to vascular plants are unresolved)

parts of corn

"Tassels" above are inflorescences of male flowers (anthers hanging). Above: corn "silk" = female styles (with stigmas) attached to ovaries ("kernels", with ovules). Ovules in the top part of this ear were not fertilized.

conifers (gymnosperms)

"cone bearers" (misleading because most gymnosperms produce cones) - largest gymnosperm phylum (~70 genera, 630 spp.) - can inhabit cold climates: most are "evergreens" & carry out photosynthesis year-round; thin needle-like leaves reduce H2Oloss; "antifreeze" keeps sap running in winter - includes the well-known pines, redwoods, junipers, cypress, & "Christmas trees" such as spruces & firs

MOST EUKARYOTE TAXA ARE UNICELLULARPROTISTS!

("ALGAE" = plant-like protists; "PROTOZOA" = animal-like protists) - True multicellularity is only found among some protist algae (e.g., seaweeds), and all plants, fungi, & animals.

Land Plants (Kingdom Plantae) evolved from Charophyte green algae

(both share a common ancestor) Land plants share traits with some red, brown & green algal protists such as: multicellularity, eukaryotic, photosynthetic autotrophs; however land plants (Kingdom Plantae) share key traits only with some charophyte green algae (now also have DNA evidence): 1. A unique way of synthesizing cellulose in their cell walls (that differs from non charophyte algae). 2. A phragmoplast forms during cell division: = a group of aligned cytoskeletal microtubules & Golgi-derived vesicles forms between daughter nuclei of a dividing plant cell, & where a cell plate will eventually develop (that will become the cell wall between daughter cells).

Cellular slime molds

(congregating mass of distinct cells) Fruting bodies for asexual reproduction.

inner disc floret

(in a composite flower head of the daisy family) any of a number of small tubular and usually fertile florets that form the disk. In rayless plants such as the tansy the flower head is composed entirely of disk florets.

outer ray floret

(in a composite flower head of the daisy family) any of a number of strap-shaped and typically sterile florets that form the ray. In plants such as dandelions the flower head is composed entirely of ray florets.

Plasmodial slime molds

(large mass of "streaming" cytoplasm without plasma membranes) Fruting bodies for sexual reproduction.

Angiosperms are also a source of SPICES

(strongly flavored plant parts that are rich in flavorful oils) : CINNAMON is the bark of a tree.

4. Dependent embryos: the 2n sporophyte EMBRYO (formed after fertilization of egg by sperm) is retained in the female gametophyte (where egg gamete was).

*This is the unique trait that causes land plants to be known as EMBRYOPHYTES.

3. POLLINATION: pollen may be dispersed by wind or animals (e.g., insects & birds)

*pollen dispersal by animals is a NEW ADAPTATION we haven't seen before! 3. A pollen grain lands on a carpel's stigma, then one n cell starts dividing to form a pollen tube that grows down the carpel's style, through the micropyle opening of the carpel's ovule, & discharges its two haploid sperm cells into the ovule.

AMOEBOZOANS

- AMOEBOZOANS have lobe- or tube-shaped pseudopodia (unlike Rhizaria) to move & engulf prey by phagocytosis.

CITRUS was first domesticated in tropical Asia.

- Citrus is an important cashcrop in Florida. -Navel oranges are sterile & seedless & propagated asexually by cuttings & grafts, all derived from the original mutated tree over 200 years ago! -The "navel" is a mutated 2nd fruit that develops on main fruit like a "conjoined twin."

2. Development of Female Gametophyte

- In a 2n ovule in an 2n ovary, a 2n megasporangium produces 4 (n) cells: one cell becomes the n megaspore that forms the reduced female n gametophyte with eight (n) nuclei: 1 egg & 7 supporting nuclei - 3 antipodal cells (unknown function) - 2 polar nuclei (will fuse with 2nd sperm) - 2 synergid nuclei (will guide the pollen tube)

1. Alternation of generations reproductive life cycle (land plants and some brown & green algae): when an organism alternates between two multicellular stages or "generations":

- The multicellular GAMETOPHYTE stage is haploid & produces haploid gametes by mitosis. - Haploid gametes then fuse to form a diploid zygote that grows (by mitosis) into the multicellular diploid SPOROPHYTE stage. - The diploid SPOROPHYTE produces haploid spores by meiosis - each haploid spore grows (by mitosis) into a new haploid multicellular GAMETOPHYTE, completing the cycle.

Angiosperms can also have ASEXUAL or "vegetative" reproduction: detached vegetative(= non-floral or reproductive) plant fragments can regrow into entire individuals that are genetically identical to the "donor" plant (i.e., they are clones).

- by fragmentation (natural, or humans take "plant cuttings") - by grafting parts from 1 plant onto another (e.g., navel oranges!) - the "eyes" of a potato are vegetative stem buds - the roots of some plants can send up shoots that develop into new plants: an aspen clone of 47,000 trees in Utah!

Mosses (bryophyte [non-vascular land plant]) structure

- elevated sporangia (capsules) helps disperse spores

pterophytes (seedless vascular plants w/ megaphyll leaves)

- ferns (most diverse: ~12,000 spp worldwide) - horsetails (only 15 spp. Worldwide, 2 FL spp.) - whisk ferns (only 17 spp. Worldwide, 1 FL spp.) - also more spp. & larger spp. During the Carboniferous

Red Algae: mostly marine & multicellular (Archiplastida)

- most abundant seaweed in coastal tropical waters - their accessory photosynthetic pigment, phycoerythrin, absorbs blue light & transfers energy to chlorophyll - blue light penetrates deeper so red algae can grow deeper than any other photoautotrophs - "coralline" red algae have CaCO3 in their cell walls & are important reef-building organisms

ORCHIDACEAE: only a few of an orchid's dust-like seeds will germinate because the seeds also require a mycor-rhizal fungus, so ADAPTATIONS for this have evolved

- pollen is released as a large mass to ensure pollination of the many ovules - many ovules produce many tiny seeds

Green Algae: mostly aquatic but also on tree trunks, in soil, and snow (Archiplastida)

- some are symbionts with fungi to form lichens - TWO GROUPS: CHAROPHYTES & CHLOROPHYTES - Charophytes most closely related to land plants (will discuss later)

Archaeplastida (supergroup 4) (Red & Green Algae)

- some unicellular - some multicellular ("seaweeds"): another independent evolution of multicellularity (so far: also brown algae) - some colonial species (e.g., freshwater Volvox)

2. Sporangia that produce walled spores: the 2n sporophyte produces n spores by meiosis in organs called SPORANGIA:

- spore walls contain sporopollenin, which makes them resistant to harsh environments(it is the most decay - & chemical-resistant polymer known!). *This adaptation allows spores of land plants to be dispersed through air (& is also seen in some charophyte algae that live at the edges of ponds where drying occurs!).

3. Multicellular Gametangia: the n gametophyte produces n gametes by mitosis in organs called GAMETANGIA.

-Female gametangia are ARCHEGONIA & produce ONE egg each & are where fertilization occurs. -Male gametangia are ANTHERIDIA that produce & release MANY sperm

Perennials

-live for many years; woody or can die back each year -most reproduce multiple times once sexually mature (trees; potatoes; roses; many other flowering plants)

ASEXUAL or "VEGETATIVE" REPRODUCTION DISADVANTAGES:

-no genetic variation to adapt to a changing environment -cannot "wait out" bad conditions (vs a seed can remain dormant) -usually fewer individuals are produced

Hornworts (bryophyte [non-vascular land plant])

-only ~100 spp. -Sporophyte is still elevated to disperse spores. -Unlike Mosses and Liverworts the sporophyte is capable of photosynthesis

ASEXUAL or "VEGETATIVE" REPRODUCTION ADVANTAGES:

-quick production of individuals -helpful if pollinators are rare -continuity of genetic makeup (good if plant is well adapted to its environment) -avoids precarious germination stage of delicate seedlings

Biennials

-require 2 growing seasons -grow vegetatively the 1st year (roots, stems leaves) -reproduce sexually the 2nd year (flower & fruit) -seldom woody (e.g., onion, cabbage, carrots, some flowers)

4. "DOUBLE" FERTILIZATION OCCURS

1 sperm fertilizes the egg & forms a 2n zygote; the 2nd sperm fuses with the 2 female polar nuclei & forms a 3n (triploid) cell that divides to becomes the 3n endosperm (cells will be food for the embryo). NOTE: DOUBLE fertilization uses TWO sperm for different purposes: (1) make a 2n zygote(2) make 3n endosperm "food" for the embryo

Gymnosperm Life Cycle

1. A mature pine tree is the 2n sporophyte& it has BOTH small, soft MALE 2n "pollen cones" & FEMALE 2n "ovulate cones." - The female cones are what you recognize as a typical pine cone. 1.a. Each 2n pollen cone contains many 2n microsporangia holding 2n microsporocytes (cells) that undergo meiosis to produce n microspores. 1.b. Each n microspore grows (by mitosis) into a n pollen grain & contains the n male gametophyte (which will later produce sperm) 2.a. Each "scale" of a 2n ovulate cone contains two 2n ovules, each with an outer protective 2n integument & each with a micropyle opening (where a pollen grain will enter). 2.b. Each 2n ovule has a 2n megasporangium with a 2n megasporocyte cell that produces a n megaspore by meiosis. 2c. The n megaspore in the ovule develops into a n female gametophyte with an n archegonium that produces an n egg by mitosis. 3. a. Pollination occurs when WIND carries an n pollen grain to a female cone, where it enters an ovule's micropyle opening & the pollen grain's male n gametophyte grows a pollen tube delivering two haploid sperm produced by mitosis. Pollen grains disperse & protect sperm & eliminate the need for a film of water, a major adaptation to living on land. Pine pollen has "wings" to increase surface area to catch the wind. 4. a. Fertilization occurs when a n sperm in the pollen tube reaches the n egg produced by the n gametophyte in a female cone's 2n ovule, creating a 2n zygote that grows into a new 2n sporophyte embryo. 5. After fertilization, the whole ovule becomes a SEED with a protective seed coat & the 2n sporophyte embryo and food reserves inside. 6. Eventually, the scales of the ovulate (female) cones separate, releasing the seeds for dispersal by WIND. 7. A seed lands & germinates: its 2n sporophyte embryo starts to grow by mitosis into a seedling It can take ~3 yrs from cone formation to mature seeds!

Gymnosperm cones

1. A mature pine tree is the 2n sporophyte& it has BOTH small, soft MALE 2n "pollen cones" & FEMALE 2n "ovulate cones." The female cones are what you recognize as a typical pine cone. most coniferous trees have both male and female cones. Female cones contain eggs. Male cones are small and soft. they produce (make) pollen. Once the pollen is released, make cones shrivel and die. when the egg is pollinated a seed develops

Nearly all land plants (Kingdom Plantae) have 5 traits that are lacking in charophyte green algae - many of which are adaptations to living on land:

1. An alternation of generations life cycle; (present in some brown & green algae, but not charophytes) - more on this soon 2. Sporangia that produce walled spores 3. Gametangia (female archegonia & male antheridia that make egg & sperm gametes, respectively) 4. "Dependent" embryos 5. Apical meristems (regions of mitotic cell division at root & shoot tips)

Angiosperm Life Cycle (long)

1. Development of Pollen Grains (will contain male gametophytes): Male 2n anthers with 2n microsporangia produce n microspores (by meiosis) that develop into pollen grains, each containing a reduced n male gametophyte made up of two haploid (n) cells: - 1 n cell will divide to form two haploid (n) sperm cells - 1 n cell will divide to produce the n pollen tube (after pollination) 2. Development of Female Gametophyte -In a 2n ovule in an 2n ovary, a 2n megasporangium produces 4 (n) cells: one cell becomes the n megaspore that forms the reduced female n gametophyte with eight (n) nuclei: 1 egg & 7 supporting nuclei - 3 antipodal cells (unknown function) - 2 polar nuclei (will fuse with 2nd sperm) - 2 synergid nuclei (will guide the pollen tube) 3. POLLINATION: pollen may be dispersed by wind or animals (e.g., insects & birds) A pollen grain lands on a carpel's stigma, then one n cell starts dividing to form a pollen tube that grows down the carpel's style, through the micropyle opening of the carpel's ovule, & discharges its two haploid sperm cells into the ovule. 4. "DOUBLE" FERTILIZATION OCCURS: 1 sperm fertilizes the egg & forms a 2n zygote; the 2nd sperm fuses with the 2 female polar nuclei & forms a 3n (triploid) cell that divides to becomes the 3n endosperm (cells will be food for the embryo). NOTE: DOUBLE fertilization uses TWO sperm for different purposes: (1) make a 2n zygote (2) make 3n endosperm "food" for the embryo DOUBLE FERTILIZATION: forms a 2n zygote & 3n endosperm (food reserve) 5. SEEDS develop from fertilized ovules that contain: a. an outer seed coat (was the ovule's integument) b. one or two "seed leaves" called cotyledons attached to the embryo c. a dormant, diploid (2n), sporophyte embryo d. triploid (3n) endosperm cells (food for early embryo) e.g., coconut milk & "meat", the white fluffy part of popcorn e.g., in some species (lima bean, below left), endosperm is put into thicker starchy cotyledons as food for the embryo 6. FRUIT DEVELOPMENT: unlike gymnosperms, the ovary develops into a fruit for seed DISPERSAL by wind, water, or animals. - Mature ovary is now a fruit with fertilized ovules (= seeds).

Five Eukaryotic Supergroups

1. Excavata 2. Chromalveolata 3. Rhizaria 4. Archaeplastida 5. Unikonta -"PROTISTS" (highlighted in yellow at left are now spread across all five Supergroups. - Kingdoms Fungi & Animalia in Supergroup 5 - Kingdom Plantae in Supergroup 4 ***NOTE the basal polytomy: the "root" (ancestral group) of all eukaryotes is unknown.

Seedless Vascular plants (ferns) vs Bryophytes (non-vascular plants) similarities

1. Like bryophytes, seedless vascular plants have the 5 Plant Kingdom features discussed earlier such as an alternation of generations life cycle, etc. 2. Like bryophytes, seedless vascular plants have flagellated sperm (that must swim to an egg) & therefore are mostly restricted to moist, shaded habitats.

Root structure

1. Most water & mineral absorption is done by delicate root hairs a. root hairs are thin extensions of root epidermal cells b. root hairs greatly increase the surface area for absorption

Stem Structure

1. Nodes = points where leaves or side branches grow 2. Apical buds = terminal buds at a shoot tip where stem elongation can occur. 3. Axillary buds = where a leaf attaches at a NODE; can potentially grow into a new stem/branch.- "apical dominance" maintain dormancy of most axillary buds so axillary buds won't grow unless the apical bud is lost or is a great distance away) (PRUNING stimulates axillary buds to Grow & creates a "bushier" plant)

Seed Dormancy: an adaptation that prevents germination& growth until conditions are suitable

1. Outer seed coat (ovule integument) protects embryo; helps prevent germination during unsuitable conditions eudicot bean seed (2 thick cotyledons instead of endosperm) 2. Recall that a plant embryo is comprised of: a. epicotyl (stem above the cotyledons) b. 1-2 cotyledons ("seed leaves") c. hypocotyl (stem below the cotyledons) d. radicle (embryonic root)

ALL (VASCULAR) SEED PLANTS SHARE

1. SEEDS: contain a sporophyte 2n embryo with a food supply & surrounded by a protective 2n seed coat. 2. HETEROSPORY: two kinds of n spores are made by meiosis:- a haploid (n) female megaspore (in a 2n megasporangium) divides by mitosis to become a female n gametophyte that will produce an n egg cell (by mitosis)- a haploid (n) male microspore(in a 2n microsporangium) divides by mitosis to become a male n gametophyte that will produce n sperm cells (by mitosis). (contrast this with homosporous ferns where only one kind of spore grows into a bisexual gametophyte that produces both egg & sperm) 3. OVULES: structures in a parent 2n sporophyte that contain an outer 2n protective integument, 2nfemalemegasporangiumcells, and the female n megaspore (produced by meiosis). - the n megaspore then grows by mitosis into a very reduced female n gametophyte inside the ovule & it will eventually produce n egg(s) by mitosis 4. POLLEN GRAINS = contain haploid (n) male gametophytes also much reduced in size that that are protected &widely dispersed & will produce n sperm (by mitosis).

POLLINATION: Prevention of self fertilization ensures "cross-fertilization" between different parent plants to enhance genetic variability among offspring:

1. Some plants have ONLY male stamens OR female carpels. 2. Some flowers will have the stamens mature BEFORE the carpels. 3. Some plants have stamens arranged to make selfing unlikely(thrum vs pin flowers, lower left). 4. MOST COMMON: "self incompatibility" = a plant can biochemically reject its own pollen

Seedless Vascular Plants life cycle

1. Start with the 2n sporophyte: what you recognize as a "fern" - n spores are produced by meiosis in clusters of sporangia called SORI (sing., sorus) located on the underside of leaves ("fronds") & then discharged (recall: elevated height) - Spores "explode" out and, like mosses, are also wind-dispersed to land far away from parent plant. 2. Each spore germinates into a very reduced, low-to-ground, bisexual n gametophyte (i.e., it produces BOTH antheridia & archegonia which produce sperm & egg gametes by mitosis, respectively). NOTE: flagellated sperm must still swim to fertilize an egg in the archegonium. 3. The 2n embryo develops into a new sporophyte (growing out of the tiny gametophyte). New sporophyte leaves are called "fiddleheads."

Seedless vascular plants ecological an economic importance

1. The extensive Devonian & Carboniferous forests of lycophytes & pterophytes REMOVED atmospheric CO2 & may have contributed to global cooling at the end of the Carboniferous & later glaciation. 2. The decaying plants of these Carboniferous forests eventually became compacted, then heat & pressure converted this to the COAL we burn today: PRODUCING vast amounts of CO2 & global warming - the irony!).

Bryophyte Ecological & Economic Importance

1. Usually found in moist, shaded habitats.(WHY? Know 2 reasons...)(but some spp. also in harsh habitats: can dry out & then rehydrate) 2. Some spp. colonize bare sandy soil & prevent nitrogen from leaching out of soil (nitrogen is essential for plant growth). 3. Some are "pioneer species" in primary succession: - they colonize bare rock & help create soil

Bryophyte life cycle (non-vascular land plants)

1. a variation on the alternation of generations life cycle 2. gametophytes (what you recognize as a "moss') are dominant (= larger & longer-living than the sporophyte phase)*** 3. sporophytes are short-lived & present only part of the time***

Plants are comprised of a:

1. root system: anchors, draws up H2O & minerals (via xylem) &can store carbohydrates-apical meristem tissue is at root tips 2. shoot system (=stems & leaves): support, photosynthesis (absorb CO2& light), transport materials in xylem & phloem -apical meristem tissue is at shoot tips

the diversification of land plants (phylogeny)

1st: charophyte green alga (non vascular bryophytes) - liverworts - mosses - hornworts 2nd: seedless vascular plants - lycophytes (club mosses, spike mosses, quillworts) - pterophytes (ferns, horsetails, whisk ferns) 3rd: seeded vascular plants - gymnosperms - angiosperms

seedless vascular plants phylogenetic overview

2 groups of seedless vascular plants: not monophyletic! LYCOPHYTA (with microphyll leaves) PTEROPHYTA (with megaphyll leaves)

seedless vascular plants

2 phyla: lycophytes: club mosses, spike mosses, quillworts pterophytes: ferns, whisk ferns, horsetails

non-vascular bryophytes

3 phyla: liverworts mosses hornwort

origin of exant seed plants

305 million years ago

gymnosperm phyla (4)

4 phyla: - conifers - cycads - ginkgo - gnetophytes

Bryophyte Ecological & Economic Importance cont

4. Peat Bogs of Sphagnum or "peat" moss are wetland habitats with low O2, low pH, & low nutrients covering ~3% of earth's land surface - peat bogs are an important reservoir for organic carbon (~30% of all soil carbon exists as peat: 450 billion tons!; helps reduceatmospheric CO2 & global warming)

origin of vascular plants

425 million years ago

origin of land plants

475 million years ago

Multiple Fruit

A MULTIPLE fruit develops from the many carpels of the MANY flowers in an inflorescence. (i.e., not a single flower).

simple fruit

A SIMPLE fruit is derived from 1 carpel or several fused carpels in ONE flower.

Prochloroccus (marine cyanobacterium)

A minute marine cyanobacterium, Prochloroccus, is responsible for producing much of the oxygen in our atmosphere by photosynthesis (~1 in every 5 breaths you take!). About 30% of all photosynthesis on Earth is performed by protists! Climate change (rising temperature & acidity of oceans) can negatively impact these photosynthetic organisms that contribute much of the oxygen in our atmosphere.

simple fruit (fleshy) - tomato

A single tomato flower has a single ovary with many ovules; each ovule can become a seed.

mutualism ex: corpse flower

A species of "Corpse Flower" is shown here. Fly-pollinated flowers often smell like rotting meat. They are typically red. Flies are drawn to the Corpse Flower to lay their eggs and pick up and/or deposit pollen.

keystone species

A species that influences the survival of many other species in an ecosystem

Eukaryotic Life Cycles: Diplontic, Haplontic, & Alteration of Generations

A. Diplontic (most animals) - diploid adults produce haploid gametes by meiosis, then fusion of haploid gametes produces a diploid zygote that grows into a new diploid individual. B. Alternation of Generations (plants, some algae) - diploid adults ("sporophytes") produce haploid spores (not gametes) by meiosis, then spores grow into multicellular haploid structure ("gametophyte") that produces haploid gametes by mitosis (unusual!), then fusion of haploid gametes produces a diploid zygote that grows into a new diploid individual ("sporophyte"). C. Haplontic (most fungi, some protists)- haploid adults produce haploid gametes by mitosis (unusual!), then fusion of haploid gametes produces a diploid zygote produces haploid spores (not gametes!) by meiosis, spores grow into a new haploid individual.

Monocot Diversity

All monocots lack secondary growth (no wood) Some are treelike but 'wood' is formed differently Most temperate forms are fairly small, tropical forms can be large. Much more conservative in form than the eudicots Major Groups: - Aroids - have a distinctive flower (spathe) and large leaves with a central vein - Lilies - Asparagus and relatives (Agave, Aloe, Irises, Onions, Orchids) - Palms - Ginger and Bananas - Bromeliads, and Grasses

Plasticity may lead to evolutionary diversity

All of these plants are in the same genus!

seedless vascular plants reproduction and water

All seedless plants rely on sperm to swim to archegonia. A major problem for out-crossing if plants are far apart. Plants can be homosporous (most ferns) and each spore produces a gametophyte with both archegonia and antheridia Or heteosporous (lycophytes, aquatic ferns) and each spore produces either a male or a female gametophyte.

About 3% of all angiosperms are neither monocots or eudicots & fall into 3 basal lineages:

Amborella water lilies star anise (~100spp.) & magnoliids (~8000 spp.)

fruit development

An OVARY (containing 1 or more ovules that will each have an egg) at the base of a flower..... ....and after fertilization of egg, it develops into the FRUIT (with seeds: each seed develops from an ovule).

Alternation of generations life cycle of large multicellular brown algae

An alternation of generations life cycle typical of many of the large, multicellular brown algae: a 2n sporophyte ("seaweed") produces n spores by meiosis that grow into n gametophytes that produce n gametes by mitosis that fertilize to form a new seaweed (2n sporophyte). What you recognize as the "seaweed" is the diploid sporophyte generation.

Plant mating systems and selfing

An individual flowering plant can have the following kinds of flowers. Perfect flowers - both carpels and stamens Male flowers - stamens only Female flowers - carpels only Most angiosperms have only perfect flowers but there is a lot of variation

MUTUALISMS (when both parties benefit) often co-evolve between plants & their pollinators.

An orchid (Ophrys scolopax) mimics a female bee (Eucera longicornis) and also produces a scent mimicking a female bee's sex pheromone to attract male bee pollinators. Bees are the most common insect pollinators, especially among crop plants. Bees learn quickly to recognize colors, odors, and outlines, and bee-pollinated plants tend to have scents and be yellow or blue, but NOT red, which they can't see. Some flowers have "landing platforms" for pollinators; at times the weight of the pollinator exposes the stamens (pollen)!

Angiosperm phylogeny

Angiosperms (Phylum Anthophyta): first recorded from ~140 MYA; diversified & eventually replaced gymnosperms as the dominant land plants.

How do Angiosperms differ from Gymnosperms?

Angiosperms DIFFER from gymnosperms by having flowers (with reproductive organs) & fruit (with seeds)

Angiosperms

Angiosperms are the most diverse & widespread of all plants (~350,000 species: almost all the plants around you!) - vast diversity: both woody & herbaceous (non-woody) species e.g., grasses, oak trees, daisies, all crops, palm trees, ivy, cacti, etc.

fruits have evolved adaptations for dispersal by animals

Animal-dispersed fruits & seeds can be dispersed externally(e.g., by BURRS catching on fur or hoarding) or internally(when eaten & pass undigested seeds through the gut & out with feces). Squirrels can digest seeds that they eat, but often forget where fruits were hoarded so enough uneaten seeds survive to germinate!

Angiosperms have different lengths to their life cycle:

Annuals Biennials Perennials

Bryophytes (non-vascular land plants) life cycle 3

Archegonia in female (n) gametophytes produce (1n) egg by MITOSIS; antheridia in male (n) gametophytes produce & release many (n) flagellated sperm by MITOSIS. *FLAGELLATED SPERM MUST SWIM THROUGH H20 TO FERTILIZE EGGS IN ARCHEGONIA.

Two Largest Angiosperm Families

Asteraceae and Orchidaceae

Feeding Modes

Autotroph - carbon source is from inorganic compounds e.g. plants Heterotrophs - carbon source from organic compounds e.g. animals

SIMPLE FRUITS CAN BE FLESHY

BERRIES (tomato, grape): outer, middle & inner layers of fruit wall are fleshy DRUPES (peaches, apricots, nectarines): the outer & middle layer are fleshy, but the inner fruit wall is hard (the "pit" or "stone") & contains the SEED. NOTE: walnuts, almonds, pecans & pistachios are SEEDS of drupes...not nuts!

mutualism ex: Long-nosed bat feeding on cactus flower at night.

Bat-pollinated flowers produce copious nectar, open at night, emit strong fermenting, fruitlike, or musty odors, and are dull colored. They are often produced on the trunk (if the plant is a tree).

Bryophyte Ecological & Economic Importance cont 2

Because soil is low in nutrients, Sphagnum bogs are unique communities often with rare & insectivorous species that are adapted to low-nutrient soils. Because a bog is low in O2 (i.e., anaerobic), dead Sphagnum moss only partly decays & layers of compacted Sphagnum are harvested & used for fuel, especially in Ireland & Canada. - dried Sphagnum "peat" moss is used as a soil additive(adds organic matter to poor soil) & to help soils retain water (dead cells form "pores" - left photo - & absorb up to 20x their dry weight in water!) because of reduced decay rates, compacted layers of peat preserve ancient remains of anthropological importance.

Seed Dormancy

Breaking dormancy requires environmental cues (temperature, water, O2and/or light changes)

Adapting to Low Light

Broad, dark green leaves Slow growth Understory plants

Chromaveolata Brown Algae (multicellular, photosynthetic)(supergroup 2)

Brown algae: the largest & most common *multicellular* algae in temperate & polar waters, mostly marine, some species grow up to 60m long (e.g., kelp)! - photosynthetic with brown carotenoid pigments in their plastids - make up most of what we call "SEAWEEDS"- represent an evolution of complex multicellularity independent of that seen in red algae & land plants.

Seedless vascular plants (ferns) history

Bryophytes were the dominant vegetation the first 100MY of plant evolution, then vascular plants began to diversify ~350 MY ago in the Carboniferous. A Carboniferous forest of seedless vascular plants (~359-299MYA; artist's rendition). These forests produced the coal we burn today.

land plants (Kingdom Plantae) have some uniquely derived traits that are lacking in charophyte green algae - many of which are adaptations to living on land.

CHALLENGES to living on land: 1. scarcity of H2O (affects gamete & spore dispersal, metabolism) 2. drying out (evaporative H2O loss) 3. support against gravity BENEFITS to living on land: 1. unfiltered sunlight 2. more CO2. 3. nutrient-rich soil 4. unoccupied space (few competitors, herbivores & pathogens (initially!!!))

mutualism ex: co-evolution in regards to pollenation

CO-EVOLUTION: hummers have long bills to reach the nectar that is at the base of a flower's long "spurs" Bird-pollinated flowers typically produce copious nectar as a "reward" and tend to be red or yellow and odorless (birds have a poor sense of smell).

Examples of Plant Adaptations: Carnivorous plants in nutrient-poor soils

Carnivorous plants in nutrient-poor soils obtain minerals (especially N) by capturing insects & other small animals. -plant releases digestive enzymes and absorbs liquified prey (pitcher plants, Venus flytrap, sundews)

Chromaveolata Ciliates (unicellular) (supergroup 2)

Ciliates (unicellular): mostly heterotrophs - have cilia (unique to eukaryotes) made of microtubules used by the cell to move & feed; - have macronuclei & micronuclei (1 or more of each per cell) - e.g., Paramecium

Coevolution and Angiosperm Success

Coevolution is evolution due to species interactions (mutualism, etc.) Simplest case - pairwise coevolution (two interacting species).Each species evolves in response to the other, and thus exerts somewhat different selection in the next generation. Angiosperms have become successful due to coevolution with pollinators, with fruit dispersers, and with mycorrizhal fungi (covered in the fungi section). Coevolution with herbivores have driven another suite of plant and chemical traits.

Secondary growth and wood

Competition for light selects for increased height in plants Problem - meristems primarily increase length but not girth If stems can't get thicker, plants can't grow tall. All groups of seed plants exhibit secondary growth in which the Xylem and Phloem reproduce laterally. Secondary growth forms wood Found in all gymnosperms and many angiosperms

Ciliates have evolved a former of pseudo-sexual reproduction

Conjugation (green arrow) produces genetic variation when 2 cells exchange haploid micronuclei that were formed from a diploid micronucleus by meiosis (NOTE: no reproduction of new cells!) 2 rounds of asexual reproduction by binary fission (blue arrow) eventually produces 4 cells after 2 haploid micronuclei fuse, making a diploid micronucleus that replicates by mitosis & produces micronuclei that fuse, forming a new macronucleus when the original macronucleus disintegrates.

cycad ex: Cycas revoluta

Cycas revoluta: SAGO "PALM" (NOT a palm!!!)

conifer ex: cypress

Cypress (Taxodium) is common in southern US swamps and rivers. It has "knees" or vertical root outgrowths (to stabilize?). "Bald" cypress is deciduous(= drops its leaves), so note that not all conifers are evergreen!

Chromaveolata Diatoms (unicellular, photosynthetic)(supergroup 2)

Diatoms (unicellular): photosynthetic - have a 2-part silica wall (when fossilized, form "diatomaceous earth", used in filters & polishes) - a major component of marine phytoplankton

Dioecious

Dioecy is a characteristic of a species, meaning that it has distinct male and female individual organisms.

Charophytes - land plant relatives

Diverse group of freshwater green algae Some are 'plantlike' (Chara, below)Others have simple bodies (Zygnema, above)

cycad facts

Dominant plant group in Mesozoic Oldest known group of plants to have insect pollinators

Amoebozoans examples

Entamoebas: potentially lethal parasites of animals; third leading cause of human deaths due to eukaryotic parasites! Entamoeba histyolytica causes amebic dysentery DOCCAM: "giant" deep-sea amoeba (pic)

gnetophytes ex: Ephedra

Ephedra plants are used for a variety of medicinal purposes such as asthma, hay fever, common cold (e.g., "Mormon Tea").

Examples of Plant Adaptations: Epiphytes ("air plants")

Epiphytes ("air plants") simply grow on host plant & make their own sugars & absorb H20 & minerals from rain (e.g., many orchids, staghorn ferns, spanish "moss", some bromeliads) staghorn fern spanish "moss" bromeliad

ASTERACEAE: "sunflower" family; most speciose angiosperm family; eudicots; ~22,750 spp.

FLORIDA ASTERACEAE: ~329 spp. native to Florida The Asteraceae have inflorescences with 2 TYPES OF "FLORETS": - outer RAY florets (left): petals are fused & floret has bilateral symmetry. - inner DISK florets (center & right): petals are fused & florets have radial symmetry. The flowers of Asteraceae can be combined in various ways in an inflorescence: - all ray flowers (top) - all disk flowers (bottom) - a combination of ray AND disk flowers (middle)(like daisies & sunflowers) In the Asteraceae, BRACTS are rings of sepal-like or petal-like structures below a flower's sepals or below an inflorescence In the Asteraceae, BRACTS are rings of sepal-like or petal-like structures at the base of an inflorescence: We eat the base of the BRACTS of an artichoke!

ORCHIDACEAE: the second-most speciose angiosperm group; monocots; ~20,000 spp.

FLORIDA ORCHIDACEAE: ~121 spp. native to FL ORCHIDACEAE: only a few of an orchid's dust-like seeds will germinate because the seeds also require a mycor-rhizal fungus, so ADAPTATIONS for this have evolved: - pollen is released as a large mass to ensure pollination of the many ovules - many ovules produce many tiny seeds a well known example is VANILLA (vanilla flavoring is extracted from the fruits (vanilla "bean") of Vanilla planifolia.

SIMPLE FRUITS CAN BE DRY & DEHISCENT (= they split open)

FOLLICLES(milkweed): formed from 1 carpel that dries & splits down one side LEGUMES(peas, peanuts, beans): like a follicle, but dries & splits down two sides

FRUITS are mature ovaries that help DISPERSE seeds

FRUITS are mature ovaries that help DISPERSE seeds (& seeds are mature ovules with embryos) a. fruits may be FLESHY (e.g., tomato, apple, grapefruit) b. fruits may be DRY (e.g., nuts, bean/pea pods in nature, grains) c. fruits have adaptations for wind, water or animal dispersal *** (e.g., fruits can be winged, edible, they can float, or be burrs that stick to animal dispersers))

Nucleariids

Fairly obscure group of freshwater and soil amoebae. Probably closest relatives of fungi Not much known about them

conifer ex: Florida yew

Florida Yew (Taxus floridana) is also a critically endangered species endemic to the bluffs and ravines along the Apalachicola River. It is dioecious: male "pollen" cones (left) & female "seed" cones (right) are produced on separate trees. Florida Yew (Taxus floridana): It's bark is the source of paclitaxel, used to make Taxol, an anticancer drug (discovered in 1967 & originally derived from the bark of the Pacific yew, Taxus brevifolia. It affects microtubles & inhibits cell division. The first direct synthesis of taxol in the lab was achieved in 1994 independently at FSU (Robert A. Holton) & the Scripps Research Institute (K.C. Nikolaou). Annual sales have been in the billions of dollars.

Kingdom Plantae: Historical Perspective and Significance

Fossil evidence indicates plants were on land at least 475 million years ago (along with fungi & animals) Since then, plants have diversified into ~290,000 extant (living, not extinct) species "General" significance of land plants: photosynthetic plants supply oxygen and are the base of terrestrial animal food chains.

Gymnamoebas

Free-living and mostly unicellular (some may have many nucleii) Some have tests (like Rhizaria) but most do not. Lobose - move by extending lobes of body Feed by phagocytosis Classification and evolutionary relationships of 'amoebas' has been uncertain.

Ginkgo (one species worldwide)(gymnosperm)

GINKGO: only ONE SPECIES (Ginkgo biloba) in the entire phylum worldwide! Called the "maidenhair tree." 1st discovered in China. This species is dioecious, and today male plants are widely planted as a Landscape tree. The female seeds, as they rot, smell like rancid butter & so female trees are avoided for plantings.

Gymnosperms

GYMNOSPERMS appear early in the fossil record (305MYA) & were the dominant land plants in the drier Mesozoic when seedless vascular plants declined (angiosperms came to dominate later).

conifer ex: Gopher wood or "stinking yew"

Gopher wood or "stinking yew" (Torreya taxifolia) is a critically endangered species that is endemic (= found nowhere else) to the bluffs and ravines along the Apalachicola River just west of us in the Florida panhandle.

Escaping Low Light

Grow when trees are dormant Vine Epiphyte Take advantage of temporary light

seeded vascular plants

Gymnosperms, 4 phyla Angiosperms: Phylum Anthophyta

ASTERACEAE: "sunflower" family; most speciose angiosperm family; eudicots; ~22,750 spp.

Helianthus anuus (Sunflower) Cirsium altissimum (thistle)

Anthropological Significance of Seed Plants

Human culture changed from nomadic hunter -gatherers to permanent settlements once humans began to cultivate & domesticate wild seed plants as food crops ~12,000 yrs ago. - early crops such as wheat, rice, maize (corn), figs - permanent settlements led to VAST social changes

modes of Sexual reproduction

Isogamy and Anisogamy dominance of haploid vs diploid stages monoecious vs dioecious selfing vs outcrossing

CO2 drawdown

It has been estimated that 100 billion tons of carbon (from CO2) is bound into carbohydrates each year by photosynthesis.

CORN (aka MAIZE) was domesticated in the Americas.

It is important to maintain wild relatives of crop plants as a source of genetic diversity: in 1977, Zea diploperrenis was discovered in Mexico. It carried the genes for resistance to 7 of the 9 major viruses that infect maize in the US. For 5 of these, no other source of resistance is known. The genes were introduced into our commercial lines. Ears" are inflorescences of FEMALE flowers (corn "silk" is an elongated stigma & style!) "Tassels" are inflorescences of MALE flowers (with anthers). Kernels are ovaries.

conifer ex: junipers

Junipers are another type of conifer. The cones of Juniperus communisre used to flavor gin! Juniper "berries" are actually the female cones with fleshy scales!

Kelp

KELP is a type of brown algae that grow in underwater "forests". Their leaf-like blades have "floats" or gas-filled "bladders" to bouy up the blades to expose them to light for photosynthesis. They are primary producers at the base of an important community along with urchins & otters off the coast of California. They are exploited as a source of alginates. Alginates are used as thickening agents in foods production (pudding), cosmetics, pharmaceuticals, et al. Otters are a keystone species & help maintain the rich kelp "forest" community by keeping the sea urchin population in check - otherwise, urchins will eat all of the kelp. There are about 1500 species of brown algae; 86 brown algal taxa are known from the Gulf of Mexico

lycophytes (seedless vascular plants w/ microphyll leaves)

LYCOPHYTES (small extant spp., with microphyll leaves) - club "mosses" (8 FL spp.), spike "mosses" (5 FL spp.), & quillworts (4 FL spp.) Lycophytes were a dominant group for millions of years in Carboniferous swamps with more spp. that grew into large TREES!

Size of Organisms

Large organisms have a large mass (volume) But a low drag (surface area) Unlikely to reach terminal velocity in biologically meaningful distances Support (and not falling over) is a major issue Small organisms have a large SA:V. Have a low terminal velocity and don't have to worry so much about gravity. Instead friction is a much bigger issue

FLORIDA ASTERACEAE: ~329 spp. native to Florida

Liatris (Blazing Star) Solidago (Goldenrod)

Charophytes life cycle

Life cycle is haplontic with a haploid multicellular Body (don't need to know details)

aggregate fruit ex: magnolia

Like blackberries, a single magnolia flower has many SEPARATE carpels so what appears to be a single large fruit is actually an aggregate fruit of many follicles that split & release red seeds.

conifer ex: long leaf pine

Longleaf pine (Pinus palustris) was once the dominant native vegetation of southeast coastal forests prior to wide-scale cutting. Today longleaf pine forest occupies just 3% of its historic range of 38 million hectares. The "grass stage" of seedlings (right) is an adaptation to survive natural fires. It is the preferred nesting tree for the endangered red-cockaded woodpecker.

How would you differentiate between a group of simple leaves and a single compound leaf?

Look for presence/absence of an axillary bud. Petiole attaches a leaf to the stem at a node where an axillary bud can appear.

lycophytes in the carboniferous

Lycophytes were a dominant group for millions of years in Carboniferous swamps with more spp. that grew into large TREES

Megaphyll leaves (all vascular plants except for lycophytes)

MEGAPHYLL leaves: have multiple veins - found in all other vascular plants

Microphyll leaves (only found in lycophytes)

MICROPHYLL leaves: usually spine-shaped with a single leaf vein.- found in only 1 group of seedless vascular plants: the lycophytes

two main leaf types among vascular plants

MICROPHYLL leaves: usually spine-shaped with a single leaf vein.- found in only 1 group of seedless vascular plants: the lycophytes MEGAPHYLL leaves: have multiple veins - found in all other vascular plants

Mosses (bryophyte [non-vascular land plant])

MOSSES:~15,000 spp. The use of "moss" in common names can cause confusion. "Spanish moss" (Tillandsia usneoides) is actually a flowering plant! e.g., "Reindeer moss" Is actually a lichen (an alga & a fungus)!

1. Development of Pollen Grains (will contain male gametophytes)

Male 2n anthers with 2n microsporangia produce n microspores (by meiosis) that develop into pollen grains, each containing a reduced n male gametophyte made up of two haploid (n) cells: 1 n cell will divide to form two haploid (n) sperm cells 1 n cell will divide to produce the n pollen tube (after pollination)

Rhizaria (supergroup 3)

Many are "amoebas" with thread like pseudopodia used to move & to capture prey: NOT the amoeba you are familiar with! - FORAMS (= "foraminiferans"): pseudopodia extend through a porous CaCO3 shell or "test" - RADIOLARIANS: pseudopodia radiate outward from a silica "shell"

mutualism ex: snapdragon landing platforms - pollenation

Many flowers, such as snapdragons, provide "landing platforms" with special cells that allow the insect pollinator to get a "better grip", and force the insect to crawl inside the flower ensuring that it picks up & also deposits pollen. dried snapdragon seed pods (fruits) resemble skulls

Reynold's Number (Re)

Measure of the ratio of inertia: viscosity for an objectmoving through fluid (or fluid over an object) Re (small) means low inertia Re (large) means high inertia Re is a function of the properties of the fluid or gas And of the size of the object and its speed

seedless vascular plants competition for light

Meristems can only grow 'up' which limits thickness and strength of stems. Many seedless plants are epiphytes Tree ferns use roots to thicken trunk.

Fundamentals of living

Metabolism - moderately variable (highly variable in prokaryotes) Biosynthesis - Mostly the same (variation in development) Reproduction - Variable

Cultivated forms of wild plant stocks have been selectively bred to produce more, larger fruit.

Modern corn (maize; bottom) was derived from wild maize("teosinte"; top) that had small kernels.

Bryophyte (non-vascular land plants) competition for light

Mosses and liverworts can't grow tall to compete for light Don't have extensive root systems Can often grow as epiphytes

Angiosperm Crops: the product of artificial selection

Most of our food (& food for livestock) comes from cultivated angiosperms; also food for livestock: 5-7 kg grain produces only 1kg of beef: recall the food pyramid of energy transfer. ****New forms can be "created" from a common ancestor (above: wild mustard) via selective breeding by humans.

Red Algae Life Cycles

Mostly alternation of generations with a twist There are two different sporophytes and one gametophyte

most conifers are drought adapted

Needles have reduced surface area for water loss. Many conifers live in dry habitats, cold habitats (water is only seasonally available), and habitats with good drainage (bald cypress is an exception).

unfertilized ovule of seed plant

OVULES: structures in a parent 2n sporophyte that contain an outer 2n protective integument, 2nfemalemegasporangiumcells, and the female n megaspore (produced by meiosis).

Chromaveolata Oomycetes (supergroup 2)

Oomycetes: - water "molds", white rusts, downy mildews - once mistaken as fungi - heterotrophic decomposers or parasites (plastids have been lost, evolutionarily) - cause of potato blight/Irish potato famine of Dead goldfish covered with the threadlike water mold Saprolegnia.

Support

Organisms need structures to support their bodies (cell walls, vacuoles, skeletons, etc.) The need for support is proportional to mass (volume) The strength of support is proportional to surface area Structural support is a lot 'easier' for small organisms Living in water usually reduces issues of support

Outcrossing

Out-crossing or out-breeding is the technique of crossing between different breeds with no common ancestors. This is the practice of introducing unrelated genetic material into a breeding line.

Anther with microsporangia

Ovule with megasporangium

seed plants: historical overview and introduction

PATTERN OF LAND-PLANT EVOLUTION: The evolution of adaptive traits for living on land began with non-vascular bryophytes (e.g., mosses) then seedless vascular plants (e.g., ferns) & culminated with the emergence ~360MYA of vascular plants with SEEDS: GYMNOSPERMS (e.g., conifers) & ANGIOSPERMS (flowering plants)

conifer ex: pine trees

PINE TREES are one of the leading sources of timber in the world. Pine "nuts" are actually edible SEEDS, not true nuts (nuts are actually a type of fruit seen in some angiosperms).

Examples of Plant Adaptations: Parasitic plants

Parasitic plants absorb food, water & minerals from their host plant. (mistletoe, Indian Pipe)

Autotrophs (carbon source is from inorganic compunds - e.g., plants)

Photoautotroph: (carries out photosynthesis) energy source: light carbon source: CO2, HCO3-, or related compounds types of organisms: photosynthetic prokaryotes (for example, cyanobacteria); plants; certain protists (for example, algae) Chemoautotroph: (carries out chemosynthesis) energy source: inorganic chemicals (such as H2S, NH3, or Fe2+) carbon source:CO2, HCO3-, or related compounds types of organisms: unique to certain prokaryotes (for example, Sulfolobus)

Heterotrophs (carbon source is from organic compounds - e.g., animals)

Photoheterotroph: (rare) energy source: light carbon source: organic compounds types of organisms: unique to certain aquatic and salt-loving prokaryotes (for example, Rhodobacter, Chloroflexus) Chemoheterotroph: (animals like us) energy source: organic compounds carbon source: organic compounds types of organisms: many prokaryotes (for example, Clostridium) and protists; fungi; animals; some plants

How to be a "plant"-lots of surface area and lounging about.

Photosynthesis is a very inefficient way of acquiring energy. An average adult female human would require a surface area the size of a tennis court to collect enough energy for her metabolism. Plants (especially big plants) have Lots of leaf surface area, Low energy lifestyle Large surface area needed for photosynthesis

mutualism ex: Flowers pollinated by butterflies and moths also offer nectar as a reward and are are often sweetly fragrant. The insects use their long mouth parts to get at the reward (co-evolution).

Pic is an orchid Darwin was aware of: the moth was unknown during his lifetime, but he predicted its existence by looking at the flower's morphology! Flowers pollinated by day-active butterflies are typically brightly colored, whereas those pollinated by night-active moths are typically white or light-colored.

conifer ex: bristlecone pine

Pinus longaeva (bristlecone pine) represents some of the oldest living individuals on our planet: up to 5000 yrs old!

Angiosperm Crops

Plant domestication began with barley & WHEAT (a grass, seeds rich carbohydrate sources) in the FERTILE CRESCENT ~13,000 yrs ago: this greatly affected the course of human culture(from nomadic to settlements and larger family size & populations). WHEAT (GRAINS are grass SEEDS; the "hull" is the fruit") After the Fertile Crescent, other centers of plant domestication emerged (orange regions on map below) & then spread. 4 largest food crops(in order): -maize -wheat -rice -potatoes Today, plants (e.g., legumes like peas & lentils) contribute ~30% of protein consumed by humans worldwide.

The major groups of land plants are informally based on the presence/ absence of VASCULAR TISSUE

Plant vascular tissue is a system of cells joined into tubes that transport water (xylem) & nutrients (phloem)

Plant Bodies and Developmental Plasticity

Plants differ from animals in having meristems and development of new structures throughout life. Many plants are highly developmentally plastic meaning their body form is heavily influenced by environmental factors

competition for light

Plants in forests have a problem - lack of light. Strategies: - Adapt to low light - Escape low light conditions

FLORIDA ORCHIDACEAE: ~121 spp. native to FL

Platanthera (7 spp. in FL) Spiranthes (Ladiestresses;18 spp. in FL)

simple fruit (fleshy) - zucchini

Pollen from separate zucchini MALE flowers will pollinate single FEMALE flowers with fused carpels so you get one simple (fleshy) fruit.

The role of primary and secondary endosymbiosis in the evolution of protists with plastids

Primary endosymbiotic event: a photosynthetic prokaryote (cyanobacteria) was engulfed by a heterotrophic eukaryote. Secondary endosymbiotic event: a eukaryote engulfed a photosynthetic eukaryote. red algae engulfed in secondary endosymbiotic event: Dinoflagellates Apicomplexans Stramenopiles green algae engulfed in secondary endosymbiotic event: Euglenids Chlorarachinophytes

Red Algae uses

Red algae is eaten as eaten as sushi wraps (nori) & dulce Red algae is also a source for AGAR: Agar is a culture medium (left), a clarifying agent in beer, and used in gel electrophoresis.

EVOLUTIONARY ADVANTAGE of seed plants:

Reduced (microscopic!) &protected gametophytes (in ovules & pollen grains) &seeds were very successful terrestrial adaptations that enabled seed plants to become the dominant plants on land, out- competing bryophytes & seedless vascular plants. Compared to the Carboniferous (left), most land plants today are SEED plants!

gymnosperm seed

SEEDS: contain a sporophyte 2n embryo with a food supply & surrounded by a protective 2n seed coat.

Vascular plants with "naked" seeds (gymnosperms)

Seed plants form two monophyletic "sister" clades: GYMNOSPERMS (with "naked" seeds; i.e., not in ovaries) ANGIOSPERMS (with seeds enclosed in ovaries thatwill mature into fruits for seed dispersal)

Angiosperm derivative trait from seed plants: seeds

Seeds: survive better than unprotected spores, can be transported long distances Seed coat Food supply Embryo

Selfing

Selfing or self-fertilization is the union of male and female gametes and/or nuclei from same haploid, diploid, or polyploid organism. It is an extreme degree of inbreeding. Selfing is widespread - from unicellular organisms to the most complex hermaphroditic plants and animals (especially invertebrates).

Sequential Hermaphrodites

Sequential hermaphroditism is a type of hermaphroditism that occurs in many fish, gastropods, and plants. Sequential hermaphroditism occurs when the individual changes its sex at some point in its life. In particular, a sequential hermaphrodite produces eggs and sperm at different stages in life. ex. clown fish

Diffusion

Small organisms have to move small amounts of substances relatively short distances. Usually don't need specialized mechanisms Vulnerable to changes in the environment, chemical attack

Chromalveolata parasites (supergroup 2)

Some are important parasites of humans and other animals with intricate life cycles that require 2 or more hosts. - Plasmodium is the parasite that causes malaria (the leading cause of human deaths due to infection by a eukaryotic parasite: ~900,000 deaths/year!) - transmitted by the bite of a mosquito vector - Toxoplasma gondii: a very common unicellular parasite that causes toxoplasmosis (serious for infants born of infected mothers).

Bryophytes (non-vascular land plants) asexual reproduction

Some bryophyte species can also reproduce asexually by fragmentation - each fragment (red box below) grows into a new gametophyte (genetically identical to the parent plant)

Bryophytes (non-vascular land plants) life cycle 2

Spores land & germinate to produce protonemata (= early gametophytes) with high surface area: volume ratio to enhance nutrient absorption (recall: no vascular tissue!) - later, a "bud" forms with an apical meristem & grows into a mature male or female gametophyte (what we recognize as "moss") that is anchored by root-like rhizoids (not true roots with vascular tissue so they do not transport water). So: Why are most moss gametophytes low to the ground? ---> no vascular tissue to transport water and nutrients up high

Excavata

Supergroup 1 unicellular organisms photosynthesizing and non photosynthesizing

Chromalveolata

Supergroup 2 all levels of complexity photosynthesizing and non photosynthesizing

Rhizaria

Supergroup 3 unicellular organisms mostly not photosynthesizing

Archaeplastida

Supergroup 4 all levels of complexity all photosynthesizing Kingdom Plantae

Unikonta

Supergroup 5 all levels of complexity not photosynthesizing Kingdom Fungi Kingdom Animalia

TUBER crops like potatoes are native to the high-elevation Andes mountains.

TUBERS are thickened portions of underground STEMS modified to store starch).

conifer ex: giant redwood

The "General Sherman" tree: one of the giant redwood trees, Sequoiadendron giganteum, the world's largest living tree by volume: 275 ft tall & at least 2500 metric tons (the weight of ~40,000 people!)

Bryophytes (non-vascular land plants) life cycle 4

The 2n zygote (fertilized egg) is "dependent" on & protected in the archegonium of the gametophyte & grows by MITOSIS into an embryo & a new 2n sporophyte. i.e., the new sporophyte grows (mitosis) out of the gametophyte***

primary endosymbiotic event

The Archaeplastida (with red & green algae & land plants) is the group of photosynthetic organisms with plastids that are descended from the primary endosymbiotic event. It is also the group that supplied photosynthetic secondary endosymbionts to most of the other photosynthetic eukaryotes. groups in green circles, not in Archaeplastida are photosynthesizing eukaryotes from the secondary endosymbiotic event

conifer leaves (pine needles)

The leaves of pines are needle-like. A FASCICLE is a very short branch of a cluster of needle-like leaves. A species of pine tends to have the same number of leaves/needles per fascicle. When the pine drops needles, it drops the entire fascicle (the short branch).

Cycads (2nd largest group of gymnosperms)

They are dioecious (male & gemale cones on separate plants) with palm-like leaves. Your text underestimates the size of the cycad group. The accepted # of species is ~300, classified into 11 genera.

Some fruits may display withered flower parts.

This end of an apple shows dried FLOWER parts: remains of sepals, stamens, styles & stigmas!

Chromalveolata (supergroup 2)(dinoflagellates, unicellular)

This group includes two subgroups (don't need to know) that were originally recognized through details of cellular morphology and later united by molecular data. Some likely arose via secondary endosymbiosis of a unicellular red algae The two subgroups of Chromalveolata are: Alveolates - diverse unicellular organisms Stramenopiles - mostly photosynthetic algae Examples: Dinoflagellates (unicellular): - an important component of marine plankton; - photosynthetic forms have plastids with red carotenoid photosynthetic pigments; - some can produce dinoflagellate blooms (= "red tides") with toxins that kill fish, invertebrates, & can harm humans & manatees (e.g., Karenia brevis in the Gulf of Mexico) - some are called zooxanthellae & are mutualistic photosynthetic endosymbionts of corals (provide O2& carbohydrates to coral host; receive protection, CO2 & nutrients in return). ***Coral "bleaching" is when the endosymbiotic zooxanthellae get "stressed" & leave the coral.***

Excavata (supergroup 1)

This is a group of unicellular protists that share certain details of cellular structure. Some lack mitochondria but in most cases this is likely a secondary loss due to being endoparasites that live in oxygen poor environments. examples: 1. Euglena - A commonly experienced excavate is Euglena which is a genus of motile, unicellular organisms that have secondarily acquired the chloroplasts of a green alga. 2. Giardia intestinalis - unicellular intestinal parasite. Causes severe diarrhea; humans get infected by drinking contaminated water 3. Trichomonas vaginalis - unicellular parasite, sexually transmitted 4. Trypanosoma - unicellular parasite transmitted by bite of a tsetse fly vector. Causes African sleeping sickness (neurological) Parasites evolve adaptations to evade host's immune response

Simple fruit: a single flower with a single carpel or FUSED carpels so you get one fruit.

This simple fruit is a dehiscent legume (splits down TWO sides when ripe).

SIMPLE FRUITS CAN BE DRY & INDEHISCENT (= they do not split open)

True NUTS: a hard fruit wall (pericarp) surrounds a seed

UNIKONTA: a diverse group

Two Clades: AMOEBOZOANS & OPISTHOKONTS

Seedless Vascular plants (ferns) vs Bryophytes (non-vascular plants) differences

UNLIKE bryophytes, vascular plants have: a. An independent dominant 2n sporophyte life-cycle phase (the haploid gametophyte phase is very reduced & transient). b. Vascular tissue (in the form of "tubes") to transport H2O & minerals(XYLEM) & organic molecules (sugar/amino acids(PHLOEM); e.g., leaf "veins" c. Xylem cell walls are strengthened with LIGNIN- this provides structural support to stems & allows vascular plants to grow tall(evolutionary advantage?) (lignin =2nd most abundant organic compound on earth!) d. ROOTS: to anchor plant (allowing greater height) & to absorb water & nutrients from soil e. LEAVES: capture light for photosynthesis.

modes of Asexual reproduction

Vegetative (budding) Parthenogenesis

Seed Germination (embryo begins to grow):

Vertical growth (cell division) at root tip & shoot tip apical meristems. a. triploid endosperm = initial food source for growth b. the radicle emerges first: anchors & absorbs water c. the shoot tip breaks through the soil surface d. 1st true foliage leaves appear, perform photosynthesis

Problem of classifying 'Protista'

Very diverse morphologically Traditionally studied by Zoologist or Botanists Often very different classifications

In the Asteraceae, BRACTS are rings of sepal-like or petal-like structures at the base of an inflorescence

We eat the base of the BRACTS of an artichoke

gnetophytes ex: Welwitschia

Welwitschia includes a single species from the Namib desert that grows very slowly & has some of the largest & long-lived leaves.

conifer cones

What we recognize as PINE CONES are female seed-bearing cones. Some cones need the heat of a forest fire to "open." A green, immature female cone. 3 of these female cones have scales still closed; 1 has scales that have separated to release its winged seeds (for WIND dispersal).

Reynold's Number is strongly affected by organism size

Why does this matter? For small organisms: - little inertia, requires constant effort to stay in motion - body shape has relatively little effect on drag - solid objects in the environment can have big effects on movement - movement is a reliable signal of where you are unless you move really fast

fruits have evolved adaptations for dispersal by wind

Wind-dispersed fruits and seeds have features that catch the wind. In the case of tumbleweed, a much larger portion of the plant is caught up by the wind. (note that the examples here are of winged fruits)

Examples of Plant Adaptations: Xerophytes

XEROPHYTES are plants adapted to arid climates by: a. thicker, waxy cuticle (less evaporation) b. stomata "pores" for gas exchange can be recessedin "crypts" (= less exposed to wind) c. losing leaves when dry & use stem for Ps d. reduce leaves to spines & use stem for Ps (cacti) e. "hairy" trichomes ("pubescence") reflect light & reduce leaf temperature; some can be sticky to deter herbivory f. succulent leaves &/or stems (store water) g. widespread, shallow root system (rapid water uptake) Know some of these plant adaptations to arid conditions.

In the Asteraceae, BRACTS are rings of sepal-like or petal-like structures below a flower's sepals or below an inflorescence:

Yellow Sunflower & Purple Thistle with lower green bracts, not sepals! Poinsettia(small central flowers & large red bracts) Dogwood(small central flowers &large white bracts)

cycad ex: Zamia pumila

Zamia pumila (found in Florida) is the only cycad native to the US.

Sorus

a cluster of sporangia spore releasing structure on the underside of fern leaves

ORCHIDACEAE ex: Vanilla

a well known example is VANILLA (vanilla flavoring is extracted from the fruits (vanilla "bean") of Vanilla planifolia.

Monocot root structure

a. A shallow mat of thin adventitious rootsthat in turn branch into lateral roots(e.g., think of lawn grass) b. adapted to sandy & "shallow soils" where rainfall is light & moisture doesn't penetrate deeply

Gymnosperm and Eudicot root structure

a. One main deeply growing tap root;- some desert mesquite plants have taproots down to 175 ft! b. Also several lateral roots coming off the tap root

Monocot vs Eudicot Traits

a. Recall: cotyledons are "seed leaves" in the seed for early nourishment of the embryo (1 vs 2 cotyledons) b. Eudicot stiffer leaves with net-like veins held in more horizontal positions to maximize light capture; monocot leaf veins are parallel. c. A ring of vascular bundles in eudicots permits ring like secondary growth (e.g., wood); vascular bundles are scattered in monocots. d. Fibrous monocot roots promote ground-level spreading (e.g., grass) vs eudicot main tap root that helps stabilize tall, often woody plants with a spreading canopy. e. Openings in pollen grains are weak areas through which the pollen tube emerges (1 vs 3). f. Differences exist in numbers of petals (3's vs 4's or 5's)

Stem (shoot) adaptations

a. Rhizomes are underground horizontal stems (shoots) just below the surface; allows a plant to "spread" by sending up vertical shoots from axillary buds & by sending down roots (e.g., irises, ginger) b. Bulbs are underground vertical stems with enlarged fleshy storage leaves for overwintering (e.g., onions, tulips, etc.)

Leaves can be modified for various functions:

a. Tendrils (e.g., pea plants, ivy) to climb b. Spines (protect; Ps transferred to the stem; cacti) c. Storage leaves (thickened leaves to store water; e.g., "succulents") d. Reproductive leaves produce plantlets that drop off e. Bracts below an inflorescence; often mistaken for sepals or petals; attract pollinators (e.g., poinsettias)

5. SEEDS develop from fertilized ovules that contain:

a. an outer seed coat (was the ovule's integument) b. one or two "seed leaves" called cotyledons attached to the embryo c. a dormant, diploid (2n), sporophyte embryo d. triploid (3n) endosperm cells (food for early embryo) e.g., coconut milk & "meat", the white fluffy part of popcorn e.g., in some species (lima bean, below left), endosperm is put into thicker starchy cotyledons as food for the embryo

A leaf has upper & lower epidermis with mesophyll ground tissue in between

a. mesophyll (where most Ps occurs) has 2 layers: - upper palisade cell layer - lower spongy layer (facilitates gas exchange)

what gives seed plants (gymnosperms) an evolutionary advantage

a. microscopic gametophytes in ovules & pollen grains develop within the parental sporophyte & are protected from environmental stress (e.g., radiation, desiccation). b. POLLEN (with sperm) can be more widely dispersed (by wind) c. sperm (in pollen) don't need water in which to swim (so seed plants can live & reproduce in many more land habitats) d. SEEDS protect, disperse, and initially feed sporophyte embryos e. SEEDS allow some sporophyte embryos to remain dormant for years awaiting favorable conditions.

flowers pollinated by WIND

a. often have petals that are reduced or absent & lack nectaries, odors, &colors. b. have large anthers that produce LOTS of pollen. c. flowers form early in the spring before the leaves.

Modified stems for storage or asexual reproduction

a. tubers are underground thickened stems for food storage as plant overwinters(e.g., potatoes: the "eyes" are nodes with axillary buds) b. stolons or "runners" are aboveground horizontal stems (shoots) that grow on the soil surface & can send up new shoots at nodes (e.g., straw-berries)

aerial "strangling" roots

aerial "strangling" roots develop from seeds landing aboveground in a "host" tree & can absorb air & moisture (e.g., some fig & banyan trees)

aerial buttress roots

aerial buttress roots on the sides of shallowly rooted trees to broaden the base for greater support in shallow soils (e.g., some figs & banyan trees)

aerial pneumatophore ("air") roots

aerial pneumatophore ("air") roots project above water; absorb air (water is low in O2); widen base for support; e.g. mangrove & pond cypress trees)

aerial prop roots

aerial prop roots on the sides of shallowly rooted trees to broaden the base for greater support in water or shallow soils (e.g., mangrove & trees)

Carl Woese (1928-2012)

based on ribosomal RNA molecular data, split prokaryotes (Kingdom Monera) into two groups (Archaea & Bacteria), & proposed a THREE DOMAIN classification of life

Brachts

beneath a flower's sepals or below n inflorescence

fern diversity (pic)

climbing fern aerial staghorn fern tree fern floating aquatic fern

lima bean is a eudicotseed with 2 thick cotyledons containing endosperm tissue

cotyledons - an embryonic leaf in seed-bearing plants, one or more of which are the first leaves to appear from a germinating seed.

Eukaryotic mitochondria and photosynthetic plastids play an important role in the flow of energy

duh... mitochondria - cell respiration plastids - photosynthesis

~ ¼ are in the monophyletic MONOCOT clade.

e.g., orchids, palms, lilies, grasses (grains), corn

Stomata are pores in the epidermis of leaves that allow passage of CO2 & O2 & H2O loss between plant & air

each stomatal pore is flanked by 2 guard cells which regulate the opening & closure of the pores to reduce H2O loss

Active photosynthetic organisms are always very small

ex. Chlamydomaonas

Annuals

flower & fruit in 1 year or less (many examples: dandelions, petunias, snapdragons, etc.) can invest a lot in reproduction but only get one chance

Flowers (angiosperms)

flowers: made of up to 4 rings ("whorls") of modified leaves including male &/or female sex organs a. outer ring of sepals (usually green, enclose flower buds) b. next ring of petals (usually colored to attract pollinators) c. next ring of stamens (male organs) - a stamen has a stalk-like filament & an anther that contains microsporangia microspore -> male gametophyte -> sperm d. an inner ring of 1 or more carpels (female organs) - a carpel's "sticky" stigma (tip) receives pollen grains - has a stalk-like style (through which a pollen tube will grow) - has an ovary at the base (with 1 or more ovules, each with a megasporangium megaspore -> female gametophyte -> egg

Anisogamy

gametes look different male gamete is smaller and more motile female gamete is larger, less motile, and built for longevity

Isogamy

gametes look the same sex assigned by + or -

Gametophyte-Sporophyte Relationship: mosses and other nonvascular plants

gametophyte: dominant sporophyte: reduced, dependent on gametophyte for nutrition sporophyte: (2n) gametophyte: (n)

Gametophyte-Sporophyte Relationship: seed plants (gymnosperms and angiosperms)

gametophyte: reduced (usually microscopic), dependent on surrounding sporophyte tissue for nutrition sporophyte: dominant Gymnosperm - sporophyte: (2n) tree trunk - male gametophyte: (n) (microscopic) inside pollen cone - female gametophyte: (n) (microscopic) inside ovulate cone Angiosperm - sporophyte: (2n) stalk - male gametophyte: (n) (microscopic) inside stamen - female gametophyte: (n) (microscopic) inside carpel

Gametophyte-Sporophyte Relationship: ferns and other seedless vascular plants

gametophyte: reduced, independent (photosynthetic, free-living) sporophyte: dominant sporophyte: (2n) gametophyte: (n)

Complete flowers (monoecious)

have all of these flower whorls (rings): Sepal Petal Stamen Carpel

RICE (the seeds of a grass) likely first domesticated in CHINA

high carbohydrate source

The flowers of Asteraceae can be combined in various ways in an inflorescence:

i. all ray flowers (top) ii. all disk flowers (bottom) iii. a combination of ray AND disk flowers (middle) (like daisies & sunflowers)

The Asteraceae have inflorescences with 2 TYPES OF "FLORETS"

i. outer RAY florets (left): petals are fused & floret has bilateral symmetry. ii. inner DISK florets (center & right): petals are fused & florets have radial symmetry.

Three ways of getting matter and energy

ingestion photosynthesis absorption

Incomplete flowers

lack 1 or more of the 4 whorls (rings) e.g., some species can be dioecious: male or female flowers

gymnosperms

land plants with "naked seeds"

AGGREGATE fruit

like a blackberry(or strawberry, raspberry) is formed from a single flower that has multiple separate carpels (a carpel = a stigma, style and an ovary with ovules).

Angiosperm derivative trait from seed plants: reduced gametophyte

microscopic male and female gametophytes (n) are nourished and protected by the sporophyte (2n)

Angiosperm derivative trait from seed plants: heterospory

microspore - gives rise to a male gametophyte megaspore - gives rise to a female gametophyte

southern hemisphere conifers

monkey-puzzle tree kauri podocarpus

Diplontic life cycle

most animals Diploid adults produce haploid gametes by meiosis, then fusion of haploid gametes produces a diploid zygote that grows into a new diploid individual.

Haplontic life cycle

most fungi and some others Haploid adults produce haploid gametes by mitosis (unusual!), then fusion of haploid gametes produces a diploid zygote produces haploid spores (not gametes!) by meiosis, spores grow into a new haploid individual.

Sepals

outermost ring of a flower

Angiosperm derivative trait from seed plants: ovules

ovule (gymnosperm): Integument (2n) Megaspore (n) Megasporangium (2n)

Alternation of Generations life cycle

plants and some others Diploid adults ("sporophytes") produce haploid spores (not gametes) by meiosis, then spores grow into multicellular haploid structure ("gametophyte") that produces haploid gametes by mitosis (!), then fusion of haploid gametes produces a diploid zygote that grows into a new diploid individual ("sporophyte").

Angiosperm Pollenation

plants have evolved adaptations for pollination by animals (insects & birds), wind or water.1. flowers pollinated by animals are usually brightly colored &may offer "rewards" such as nectar. About 65% of angiosperms require insects for pollination. Insect pollinators can detect light reflected in the UV range.

Angiosperm derivative trait from seed plants: pollen

pollen grains make water unnecessary for fertilization

Robert Whittaker (1920-1980)

proposed 5 kingdom classification of life prokaryotes were placed in kingdom monera, all eukaryotes were places among the other four kingdoms

Unikonta

protists plus animals & fungi

Angiosperms, like gymnosperms, share the 5 derived traits of vascular seed plants

reduced gametophytes heterospory ovules pollen seeds

fruit types

simple aggregate multiple

Monoecious

simultaneous hermaphrodites (of a plant or invertebrate animal) having both the male and female reproductive organs in the same individual; hermaphrodite. ex. banana slugs

resurrection ferns

some ferns can dry out almost completely in times where there is little water, but rapidly absorb it when it does rain.

bryophyte sporophyte & gametophyte structure

sporophyte (2n) top part of plant, capsule, seta (stalk), foot gametophyte (n) bottom part

storage roots

storage roots store food & H2O in plants that overwinter(beets, radishes, yams)

Bryophytes (non-vascular land plants) life cycle 1

tart with a temporary 2n sporophyte: grows out of the top of a gametophyte - produces n spores by MEIOSIS in a sporangium (capsule), which then discharges spores (up to 50 million!) - Why is it adaptive for the capsule to be ELEVATED? ---> so the spores can travel farther

leaf structure

the main photosynthetic organ 1. A flattened blade (surface area exposed to light) 2. A petiole (stalk) attaches a leaf to a stem at a node(often lacking in monocot leaves) 3. Simple leaves have an undivided blade 4. Compound leaves have a blade divided into leaflets 5. Doubly compound leaves have leaflets that are divided 6. A leaf has upper & lower epidermis with mesophyll ground tissue in between a. mesophyll (where most Ps occurs) has 2 layers: - upper palisade cell layer - lower spongy layer (facilitates gas exchange) 7. Stomata are pores in the epidermis of leaves that allow passage of CO2 & O2 & H2O loss between plant & air a. each stomatal pore is flanked by 2 guard cells which regulate the opening & closure of the pores to reduce H2O loss 8. Leaf veins are vascular bundles (continuous with stem xylem & phloem vascular tissue)

Conditions for being a truly multicellular organism (as opposed to simple colonies or filaments of single cells)

the organism's cells arose from a single cell (e.g., zygote) by cell division & are therefore genomically equivalent cells remain attached there is specialization among cells (division of labor) a cell removed would likely die if left on its own

Opisthokonts (2nd clade of unikota)

these include animals, fungi, and 2 protistan groups The 2 protists are nucleariids & choanoflagellates

mixotrophs

these organisms use both heterotrophic and autotrophic modes of nutrition they are very rare

Amoebozoan Slime Molds:

two types: plasmodial and cellular slime molds

Green Algae: Chlorophytes

unicellular (e.g., freshwater Chlamydomonas) colonial (e.g., freshwater Volvox) multicellular seaweeds (e.g., marine "sea lettuce", Ulva)

6. FRUIT DEVELOPMENT

unlike gymnosperms, the ovary develops into a fruit for seed DISPERSAL by wind, water, or animals. a. Some fruits may display withered flower parts. b. The outer ovary wall becomes the outer pericarp of a fruit. c. Fruits may have fleshy or dry pericarps (tomato & nuts, respectively)

Angiosperm origins

we still do not fully understand how angiosperms with their flowers & fruits evolved from earlier seed plants (dotted line in phylogeny below).

vascular plants have

xylem - water transport phloem - nutrient transport

Fiddlehead

young sporophyte fronds/leaves

Eudicot Diversity

~ 2/3 of all angiosperm species are eudicots: vast diversity! e.g., small herbaceous (green) flowering plants, woody shrubs and trees Hard to summarize - great evolutionary flexibility Similar forms (convergent evolution) appear over and over again in different evolutionary lineages.

Gnetophytes (gymnosperms)

~75 spp. in 3 genera.

Liverworts (bryophyte [non-vascular land plant])

~9000 species ("spp.") - some with liver -shaped gametophytes - some with flattened "thalloid gametophytes - some with "leafy" gametophytes - sporophytes usually too small to see