BIS 2C MIDTERM 2

Differences between gymnosperms and angiosperms

- Gymnosperms: you can have 2 sperm fuse with 2 eggs

Pollen, Seeds, and Wood contribution to the success of seed plants

- In seed plants, the gametophyte generation is reduced even more than in ferns. - The haploid gametophyte develops while attached to the sporophyte. - Sperm is transferred via pollen grains, so fertilization does not require water.

Nonvascular plants

- Liverworts, mosses, and hornworts; thought to be similar to earliest land plants. - With no vascular transport system, they cannot grow very tall because vascular tissue provides support and water transport upwards. - They have a thin cuticle, and most live in moist habitats. - Nonvascular plants lack true leaves, stems, and roots but have analogous structures. - Water transport is via diffusion and capillary action. - The gametophyte is the familiar, photosynthetic form. - The sporophyte may or may not be photosynthetic but is always gets at least some nutrition from the gametophyte and is permanently attached to it. -In nonvascular plants the gametophyte is larger, longer-lived, and more self-sufficient than the sporophyte. - The haploid gametophyte produces gametes in archegonia and antheridia. - Sperm must swim or be splashed by raindrops to an archegonium to fertilize an egg. (life cycle depends on water) - Zygote develops into the multicellular, diploid sporophyte. - Consist of Liverworts, Mosses, and Hornworts and are collectively called Bryophytes

Hyphae

- Make up mycelium - Mycelium has the mass of hyphae

Seed Plants Life Cycle

- Microspores divide mitotically to produce the male gametophyte, or pollen grain. - Pollen grain walls contain sporopollenin, the most resistant biological compound known; from chemicals and dehydration.

Samara

- One or two seeded fruit - Outgrowth of ovary wall serves as wing

Chytrids

- Only fungi with swimming stages - Swimming cells have been lost in...

Accessory Fruit (Angiosperms)

- Organs other than ovary contributes to fruit - Each "seed" is a fruitlet, complete with mature ovary wall

Functions of Fruits

- Protect the next generation contained in the seed - Attract animals that will help disperse seed - Usually parts fragment to help disperse siblings far from each other.

Secondary Growth

Increase in girth (width) - Occurs through the production....

Sporophyte Growth Traits

Liverworts=NA Mosses=apical Hornworts=basal Lycophytes=apical Horsetails=apical Whisk Ferns=apical Leptosporangiate ferns= apical Gymnosperms=apical Angiosperms=apical

Embryo

The developing stage of a multicellular organism as soon as the zygote divides into more than one cell.

Oogamy

sexual reproduction in which one of the gametes (the egg) is large and nonmotile and the other gamete (the sperm) is smaller and motile

Mosses

soft, small, green and nonvascular and are found on the ground near water.

Club Mosses

the earliest group of seedless vascular plants -dichotomous branching -have microphylls (small leaves) -Have strobili (is a structure will lots of leave like structures that hold a cluster of sporangia)

Haplontic Life Cycle

the mature organism is haploid and the zygote is the only diploid stage. The organism is multicellular only in the haploid stage.

Diplontic Life Cycle

the organism is diploid and the gametes are the only haploid stage. The organism is multicellular in the diploid stage.

Zygote

the single diploid cell resulting from the fusion of two haploid gametes.

Liverworts

a nonvascular plant that's shaped like a human liver. found growing as a thick crust on moist rocks or soil along the sides of a stream. -Have root-like single celled rhizoids

Where is food stored in the gymnosperms?

In the female gametophyte

Angiosperms

- Flowering plants

Angiosperms

- Flowers function in pollination - Inflorescences make attractive

Types of Flowers

- Flowers that contain all four types of organs are called complete - Flowers that contain both male (anthers) and female (carpels) parts are called perfect or hermaphroditic - Flowers with either male or female parts missing are imperfect - and thus either female or male flowers

Fungi

- Fungi are the principle decomposers of cellulose, lignin, and keratin. - Without fungal decomposers, Earth's carbon cycle would fail; carbon would be buried. - Saprobic fungi return carbo to carbon cycle. - Very important for maintaining ecosystem

Absorptive Heterotrophy

- Fungi digest food outside their bodies by secreting digestive enzymes to break down large food molecules, then absorbing the breakdown products. - Many are saprobes (absorb nutrients from dead organic matter); still others are mutualists

Dispersal of Fungi

- Grow many spores so they can remain dormant - Use spores for dispersal

Seed Plants (Spermatophyta) - two main groups

- Gymnosperms - Angiosperms

Function of Flower

- Protect the reproductive parts - Attract pollinators - Provide rewards/landing platforms for pollinators - All these factors usually help promote cross pollination and prevent self pollination

What is the advantage of double fertilization?

- Resources are only allocated to fertilized ovules - Prevents wasteful allocation to the gametophyte that may not see a fertilization event - This allows for more nutrients to be allocated in the in a precise manner.

The Evolution of Plants

- The major clades of Plantae evolved from the first photosynthetic eukaryote. - Key evolutionary innovations evolved among the aquatic Plantae. - Land plants fall into seven major clades.

Seeds

- Undergo dormancy and provide the next generation with a growth advantage - led to domination of the landscape by seed plants

Yeast

- Unicellular Fungus - Not a monophyletic group - Free-living - Not a taxonomic group - live in liquid or moist environments, and can absorb nutrients.

Mycelium

- Very large surface area to volume ratio - Good for absorptive heterotrophy; all the hyphae are close to their food source.

Seed Plants - Primary Growth Apical (tip) growth

- also known as primary growth - occurs from division of a meristem cell or cells at the apex of the shoot or root. - branches can arise from bifurcation of the tip (dichotomous) or from axillary meristems - primary growth in vascular plants produces primary xylem and phloem (in addition to other tissue types)

Phloem

- major cell types are sieve tubes & companion cells - both are alive, BUT sieve tubes lack nuclei at maturity - both cell types are thin walled - sieve tubes and companion cells are sister cells, and have many plasmodesmatal connections -Major function is to transport the products of photosynthesis to the rest of the plant - sucrose is imported into system by an active mechanism requiring ATP - water flows in passively to osmotically balance the system - this creates positive pressure at the sucrose loading end and pushes the solution along the phloem - at the unloading end passive & active mechanisms unload the sugar, flow is NOT unidirectional

MRCA of Land Plants

-Alternation of generations -Protected embryos -Sporangia and gametangia -Sporopollenin -Cuticle -Mycorrhiza

What are the challenges to life on land?

-Drying out -Structural support -Extreme environments -UV- and photo-damage -Transport of water and nutrients -Gamete dispersal

Ferns

-Have megaphylls that are large and have complex layer of vascular veins running through them -Main stem became prominent and dichotomous branching was lost -Megaphylls arose by a fusion of branches

What are the advantages of life on land?

-More CO2 -More light for photosynthesis -More mutualistic interactions -Exploring a new niche --no competition --no predators

All Land Plants share the following features:

1. Eukaryotic (have chloroplasts & mitochondria) 2. Photosynthetic (Chlorophyll A and B) 3. Store starch in chloroplasts 4. Multicellular 5. Retain egg on parent plant 6. Retain fertilized zygote (embryo) on parent plant through early development (Embryophytes) 7. Have alternation of generations

Clicker question In the Haplontic (haploid) life cycle seen in some algae, gametes: A. Are made by mitosis B. Are the product of fusion of two cells C. Are made by meiosis D. Undergo cell divisions to make the new organism

A

Alternation of Generations

A life cycle in which there is both a multicellular diploid form, the sporophyte, and a multicellular haploid form, the gametophyte; characteristic of plants and some algae. - Expansion of haploid and diploid phase through mitosis - A diploid spore-forming organism gives rise to a haploid gamete-forming organism - When haploid gametes fuse a diploid individual is formed - Both stages multicellular and undergo mitosis

Plantae

A major Eukaryotic group where: •Primary Endosymbiosis Produced the First Photosynthetic Eukaryotes •Key Adaptations Permitted Plants to Colonize Land • Vascular Tissues Led to Rapid Diversification of Land Plants They Include: • Streptophytes: All green algae other than chlorophytes, plus land plants. • The multicellular coleochaetophytes and stoneworts are the closest relatives of land plants. • Both groups retain eggs in the parental organism, as land plants do, and the cells are connected by plasmodesmata.

Moniliphytes

A plant clade that includes ferns and horsetails

Clicker Question Plants need Oxygen to survive. A. True B. False

A. True; Plants have mitochondria and do oxidative phosphorylation especially in parts underground

Clicker Question Planetary CO2 levels are linked to seasonal variation in vegetation. A. True B. False

A. True; Temperature can also be changed by the CO2 levels.

Advantages and Disadvantages of Mycelium Growth Style

Advantages: - Disadvantages:

Rhyniophyte

An Ancient Relative of the Vascular Plants • Earliest vascular plants (now extinct): - Rhyniophytes (Silurian) had a simple vascular system and dichotomous branching but lacked leaves and roots. -- They were anchored by rhizomes (horizontal portions of stem) and rhizoids (water-absorbing filaments).

Difference between spore and gametophyte

As soon as a spore undergoes mitosis, it becomes a gametophyte

Clicker Question Which one is true? A. Ferns have alternation of generations and mosses do not. B. Ferns have dominant sporophyte and mosses have dominant gametophytes. C. The embryo is retained on the parent in moss but not in fern. D. Ferns have diplontic life cycle, mosses have haplontic life cycle E. Both (B) and (D)

B

Clicker Question The"Bryophytes" have a life cycle characterized by a prominent, independent gametophyte generation: A. False B. True

B

Clicker Question Heterosporous plants produce two types of gametes while homosporous plants produce one type of gamete A. TRUE B. FALSE

B

Clicker Question In the NASA video we saw a massive droplet of water. Without this feature the droplet would not form: A. Lack of gravity in space B. Hydrogen bonding of water C. Things are weird in space D. The air in the space station repels water

B

Which of the following statements is INCORRECT? A. The heterosporous life cycle is a form of alternation of generations B. Heterospory originated once in land plant evolution C. Heterospory involves separate male & female gametophytes D. Spores in heterosporous plants differ in size

B

Mutualistic Relationships

Both partners benefit ie. lichens, mycorrhizae

Clicker Question A tree fern can get really tall and above ground because: A. It does not require water for fertilization. B. The sperm have lost the ability to swim. C. The gametophyte generation is small and close to the ground. D. The fern cannot reproduce sexually E. Both (B) and (D).

C

Clicker question In the animal (Diploid) life cycle, gametes: A. Are made by mitosis B. Are made by shedding of a cell in the haploid body C. Are made by meiosis D. Undergo cell divisions to make the new animal

C

Where do you think ATP is used in transport in the phloem? A. Movement of water into the sieve tubes B. Movement of sucrose and water through the sieve tubes C. Movement of sugar into and out of the sieve tubes D. Movement of water in the xylem E. Movement of water out of the sieve tubes

C

Pollination

Happens when a pollen grain lands near a megagametophyte

What was required for the evolution of the seed?

Heterospory, Mircrospores and Megaspores

Clicker Question Your lecture theater is constructed on a wood framework. MOST of the mass of this wood came from: A. Water taken up by the roots B. Both water and dissolved minerals taken up by the roots C. Carbon dioxide from the air D. Nitrogen taken up by the roots E. Substances obtained through fungal and other symbioses

C; Makes up the structural support of the tree and the body of the tree

Pathogenic Fungi

Cause diseases in both plants & animals

Clicker Question Which of the following organisms would show this type of life cycle : A. "Bryophytes" B. Equisetum C. Selaginella D. A and B E. A, B and C

D

Clicker Questions Secondary growth leads to increase in: A. Transporting tissue B. Supporting tissue C. Protective tissue D. All of the above

D

Clicker Question Which of the following structures is haploid? A. Liverwort rhizoid B. Moss Spore C. Moss leafy shoot D. Cell in jacket of antheridium E. All of the above

E

Clicker Question Which statement about alternation of generations is false? A. The life cycle includes both multicellular gametophytes and multicellular sporophytes. B. Gametophytes produce gametes by mitosis. C. The gametophyte is produced by mitosis of a spore. D. Spores are haploid. E. Sporophytes produce spores by mitosis.

E

Clicker question Vascular tissue in land plants performs the following functions: A. Transport of water B. Support of the plant body C. Transport of carbohydrates D. A and C but not B E. A, B and C

E

Phragmoplast

In dividing plant cells in cytokinesis, a structure formed by overlapping microtubules that guide vesicles containing cell wall components to the middle of the cell. They then form tiny gaps when trying to fuse which are called plasmodesmata, which allow plant cells to all be connected to each other.

Parasitic Fungi

Facultative: can grow on living organisms but also grow on their own Obligate: grow only on specific host species - Insects and plants are the mist common hosts

Archegonia

Female reproductive part of a nonvascular plant (n)

Antheridia

In nonvascular plants, the male gametangium, a moist chamber in which sperm develop. (n)

Gymnos

Naked

In order for Alternation of Generations...

Need a unicellular haploid that goes through mitosis and becomes diploid and vice versa (with meiosis)

Legume

One carpel, splits on two sides

Symbiotic Relationships

Partners live in close permanent contact

Meristems

Plant tissue that remains embryonic as long as the plant lives, allowing for indeterminate growth.

Evolution of Plants Through Time

Plantae first started with endosymbiosis with cyanobacterium (chlorophyll a, phycobilins, peptidoglycan in chloroplast) and then a cellulose cell wall. Glaucophytes branch off and retain all of those characters then everything beyond lose peptidoglycan. The Red Algae and Green plant clades are created after the green plants lose their phycobilins. Red algae then branch off and lose their flagella. Green plants branch and Chlorophytes (most "green algae) are formed along with Streptophytes after a Multilayered structure is developed by algae, so that their flagella are no longer symmetrical. Streptophytes split into Other "green algae" and a new clade characterized by a phragmoplast. The phragmoplast clade then branches into Coleochaetophytes ("green algae") and a clade characterized by branched apical growth (meristems). During the meristem clade oogamy is also derived. The meristem clade then branches into the Stoneworts ("green algae") and Land Plants (embryophytes) which are characterized by a protected embryo, cuticle, multicellular sporophyte, gametangia, and thick-walled spores.

Hornworts

The sporophytes of hornworts can reach 20 cm in height. Gametophytes are flat plates a few cells thick. Sporophytes fully attached to gametophyte and does a little photosynthesis.

Vascular Plant Characteristics

Tracheids, branching sporophytes, and rooting structure

Angio

Vessel/Container

Clicker Question Why does the entire water droplet cling to the astronaut's hands? Why are droplets round?

Water clings due to hydrogen bonding and adhesion to hydrophilic surfaces. Surface tension makes drops round.

Clicker Question Which statement about plant life on land is true? a. The cuticle is missing in the non-vascular land plants. b. Some land plants are unicellular. c. Land plant spores have thin walls. d. All land plants develop from embryos.

d

Clicker Question The "Bryophytes" are not monophyletic yet they share many structure and life cycle features. These features likely represent: a. Synapomorphies. b. Convergent evolution. c. Coincidence. d. Features present in the first land plants.

d. These are features likely present in the MRCA of all land plants

Horsetails

include extinct woody trees; hollow, ribbed stems that are jointed at nodes; strobili bear spores. Stems, branches, and leaves are green (photosynthetic) and have rough texture due to silica (SiO2). Have tiny megaphylls leaves

Lycophytes

includes club mosses, spike mosses, and quillworts. These lack seeds.

Xylem

vascular tissue that carries water upward from the roots to every part of a plant. Consists of thin transport tubes called tracheids and large transport tubes called vessels. - major cell types are tracheids or vessels with thickened cell walls - these conducting cells are dead at maturity - no energy required for water movement - xylem also provides structural support to the vascular plants -no energy required for water movement -movement of water is called transpiration - water movement relies on the properties of water that include cohesion, tension and adhesion - evaporation from leaf surfaces is the main pulling force - water in xylem is under negative pressure or tension - Water flow in the xylem is unidirectional, from root to shoot tips

Key Adaptations Permitted Plants to Colonize Land

• Adaptations of land plants: - Cuticle—waxy coating that retards water loss that plant cells secrete to seal off cells from atmosphere - Stomata on stems and leaves; regulate gas exchange in order to reduce water loss - Gametangia—organs enclosing gametes to protect reproductive structures (sporangia) - Embryos in a protective structure - Pigments that protect against UV radiation - Thick spore walls that prevent desiccation & decay (sporopollenin) - Mutually beneficial associations with fungi (mycorrhizae) that promote nutrient uptake from soil

Advantages of Heterospory ?

• Different sizes and numbers of male and female gamete producing spores • Differential resource allocation between male and female gamete bearing structures (gametophytes) • Small microspore/gametophyte helps in male gamete dispersal • Large megaspore/gametophyte provides a nutritive advantage to the next generation

Road to Seeds

• Early vascular plants were homosporous - one type of spore. • Spores produce one type of gametophyte - both female & male gametes. • Some vascular plants were heterosporous - two type of spores. • ALL seed plants are heterosporous.

Vascular plants made land more habitable

• Herbivores were initially absent on land, which helped make the first vascular plants successful • These plants then made the terrestrial environment more hospitable to animals, which moved onto land only after vascular plants became established.

Heterosporous plants

• Heterosporous plants produce two spore types: - Megaspores develop into female gametophytes— megagametophytes, which produce only eggs. - Microspores develop into male gametophytes— microgametophytes, which produce only sperm.

Seed Plants- Secondary growth

• Increase in girth (width) - known as secondary growth - occurs through the production of more vasculature - produced from a lateral meristem or cambium - ancestral vascular plants could make more xylem but not more phloem- unifacial cambium - in seed plants the vascular cambium is bifacial (two-faced) produces xylem (inside) and phloem (outside)

Seedless vascular plants

• Seedless vascular plants had limitations to habitats that could be occupied. • Swimming sperm were an essential feature of the SVP life cycle. This tied the gametophytes to moist habitats! • This dependence on water was removed in seed plants.

Closest relatives to the Land Plants

• Stoneworts are thought to be the sister group of land plants. • They have a branching and apical growth form, as in most land plants. • The close relationship of stoneworts and coleochaetophytes to land plants has been confirmed by gene sequencing.

Key Vascular Plant Traits

• Water and food was transported throughout the body, allowing spread to new environments and rapid diversification. • Xylem also had a support function, leading to taller size with better competition for light and spore dispersal. • Branching, independent sporophyte that could produce more spores and develop in complex ways. • The sporophyte became the familiar, photosynthetic form; as an adult it is nutritionally independent from the gametophyte.