Bio Exam 3

Spores vs. Seeds

"A spore consists of a single cell and contains no preformed embryonic parts. In contrast, a seed typically has hundreds or thousands of cells, forming an embryo and a specialized tissue that stores food: the endosperm. All this is enclosed in a usually tough, multicellular outer wall: the seed coat. Moreover, spores and seeds differ in what they give rise to. A fern spore gives rise to the prothallus of the gametophyte generation; a seed, to the baby plant of the new sporophyte generation."

heterospory

"Advanced" feature All gymnosperms All angiosperms Leads to the SEED And POLLEN

Defining Algae

- Kingdom Protista - Pigment types (chlorophyll a, b, c, and phycobili pigments) - Cell Covering: cellulose, silica, naked, calcium

Cool Plant Caluerpa taxifolia

- invasive, killer algae - grows with vigor, resists cold water - aquarium clones (cutting algae and distributing it) - finds it way into the Mediterranean sea - eliminates other plants and fish (highly toxic) - creates new equilibrium (dense, uniform carpet) a system was designed to kill this prohibited algae with chlorine

Ginkgo (Ginkgoales)

1 species Unknown in wild, previously widespread Swimming sperm and fleshy seed coat

Double Fertilization Process

1. Pollen tube grows through stigma 2. Germ cell in pollen grain divides and releases 2 sperm cells (n) 3. Tube grows through embryo sac (female gametophyte) 4a. one sperm cell fuses with the egg, producing the 2n zygote 4b. the other sperm fuses with 2 polar bodies at the center of the sac, producing the 3n endosperm tissue Embryo feeds off endosperms, develops inside embryo sac surrounded by a protective seed coat

Characters Linking Gnetales to Angiosperms

1. flower-like reproductive parts 2. vessels in secondary wood (xylem) 3. reduced female gametophyte 4. leaves with netted venation (gnetum) 5. sugar-rich pollination droplet 6. double fertilization

Red Algae (Rhodophyceae) Fossil Record

1.5-2 billion years ago about 5,500 species mostly marine (seaweeds)

Cycad (Cycadales)

130 species old world tropics monophyletic All with coralloid roots Symbiosis with Nostoc (cyanobacteria) Converts N Nodules Occupy poor habitats swimming sperm two families: cycadaceae and zamiaceae

Defining Gymnosperms

15 families 75-80 genera 820 species All woody (trees, shrubs, lianas) Dominant vegetation colder & arctic regions Tallest, most massive, longest-lived* Reproduction slow

Alage

2 Domains: Eukaryotes and Bacteria Kingdom: Protists (except for cyanobacteria) and were mostly unicellular things (very simple)

Bryophyte sporophyte

3 parts: capsule, stalk, and basal foot spores produced in capsule

Conifers

600 species in 7 families Most important gymnosperms Pine, spruce, fir, cedar, etc. Complex seed cones 300 mya - Carboniferous

Gnetophytes

90 species, 3 genera Xylem vessels Double fertilization Transition to angiosperms?

monophyletic group

A group of species that includes an ancestral species and all of its descendants fern allies are NOT a monophyletic, but ferns are

Anthophyte Hypotheis

Angipsperms and Gnetophytes are the only extant members of a clade called "Anthophytes" Gnetales are a sister group to Angiosperms and this precursors to flowering plants

Cool Fern Azolla

Aquatic

Cool Plant Pinus longaeva

Bristlecone Pine longest living tree 4,000+ years old

Pteridosperms

Carboniferous seed ferns May not really be ferns "Primordial seed plants"

Hornworts

Cool symbiosis Nostoc Colonies Cyanobacterium converts nitrogen gas into ammonium Hornwort secretes mucilage with carbohydrate

Where did Angiosperms come from?

Darwin's "Abominable Mystery" Flowering plants: early Cretaceous (130-120 MYA) No fossils showing the Gymnosperm-Angiosperm transition Answer hinges largely on the ID of a sister group among extinct and extant plants. Hypotheses: 1. "Anthophyte" Hypothesis 2. "Gnephine" Hypothesis

Seed

Develops from an ovule. Ovule = integumented megasporangium

Ferns and Fern Allies

Devonian Period (400-350 mya) First Vascular plants First tetrapods First terrestrial anthropods later: first seed plants

Fern Morphology

Dominant generation: independent sporophyte Body consists of three organs: Underground rhizome (stem) Adventitious roots Fronds (leaves)

Monilophytes

Eusporangiate, Leptosporangiate, Horsetails, and Whisk ferns actual ferns

Gymnosperms

Extant seed plants produce seeds and pollen but no flowers or fruit seed is NOT enclosed in a fruit

Economic Importance of Algae

Food Bioremediation Vitamin Supplements Environmental Indicators Biotechnical Applications (biofuels)

Phaeophyceae (Brown Algae)

Fossil Record - 490 mya 1,500 species mostly marine, few fresh water live attached to surfaces can be over 50 meters long

fern morphology

Free-living gametophyte Also called a prothallus Produces sperm and eggs Sporophyte starts attached

Bryophyte Reproduction

Gametophytes produce gametes in specialized structures Called GAMETANGIA Eggs produced in ARCHEGONIA Eggs remain in structure Sperm produced in ANTHERIDIA Sperm released into water Sperm finds the egg zygote forms remains in archegonium develop into: Embryo (sporophyte remains dependent)

Green Plants

Green Algae, Bryophytes, Lycophytes, Monilophytes, Gymnosperms, Angiosperms all have chlorophyll b and store starch monophyletic

Gymnosperm domination

Gymnosperms could thrive even when warm, moist conditions shifted. Gymnosperms became dominant and remained so until about 65 mya Mass extinction, followed by radiation of angiosperms

What trees did dinosaurs eat?

Gymnosperms dominant dinosaurs had modifications for eating pine cones dinosaurs are so big because the trees are so big and tough to eat, generating metabolic heat within the dinosaur (mesotherm)

Production of 2 forms of Spores

Heterospory MALE - Microspores tiny, produce male gametophytes with sperm FEMALE - Megaspores larger, produce female gametophytes with eggs

Fern allies

Historically recognized grouping: Lycopods, Quillworts, Spikemosses, Horsetails, Whisk ferns Fern-like but not "true ferns"

Gymnosperms ---> Angiosperms

Hypothesis A: - gnetohpyes are closest relatives to angiosperms Hypothesis B: - all gymnosperms are closest relative to angiosperms

Angiosperms

Most dominant plant group on Earth Prettiest plant group on Earth Most economically important plant group on Earth 89% of terrestrial plants are Flowering Plants

Mariculture

Nori farming/cultivation very complex life cycle Kathleen Drew Baker + Japanese farmers figure out life cycle and create an industry from it (global collaboration)

Cool Moss Sphagnum

Peat moss (wetland moss) decay resistant form peat bogs/peatlands covers 3% of the earth's surface more than 10,000 years old Tollund man found in 1950 is 2,000+ years old and is completely preserved by the peat moss explosive spore liberation

5 Types of Conifers

Pinaceae: temperate Araucariaceae: dinosaur looking, old tree Podocarpaceae: tropical Taxaceae: Arils (seed with outside fleshy coating) and Taxol: used in chemotherapy Cupressaceae: very long lived and large trees (sequoias)

Ecological Importance of Algae

Primary Producers (photosynthesis) starting point of food chain Global Cycling of Nutrients (C, N, O2) Basis of complex communities

Advantage of Heterospory

Retention and protection of gametophytes Sperm no longer sent out on their own to "swim for their life" No water needed Eggs protected, megagametophyte supported Allowed the evolution of the seed and pollen grain

Advantages of seeds

Seeds are "better" than spores for dispersal - Seeds can remain dormant. - "Wait" for better conditions.(Spores are short-lived) Seeds have seed coat (integument). Resist mechanical damage and pathogen attack. (Spore walls tough, but thinner) Seed coats can be modified for dispersal.Shaped like wings or fleshy.

Gymnosperm Reproduction

Seeds develop from ovules after egg cells within ovules are fertilized

Gymnosperm Seeds

Seeds exposed on surfaces of leaflike structures (sporophylls) aggregated into cones no ovaries so no fruits

Cool Fern Tree Fern

Spherical sori - Eusporangiate

Leptosporangiate ferns

Sporangia delicate - walls only one or a few cell layers thick, and areas where sporangial cells are modified for dehiscence

Eusporangiate ferns

Sporangia thick-walled, lack specialized zones of dehiscence Primitive like early vascular plants and Lycophytes

Cool Plant Liquidambar styraciflua

Sweetgum - spikey ball of seeds - resin can be chewed - star shaped leaves - bright red fall color

Algae Habitats

Ubiquitous (can live anywhere) Aquatic, terrestrial, snow can often from symbiotic relationships

Chlorophyta Growth Forms

Unicells filaments colonies thalli

Fern Life Cycle

Unit of dispersal = spores Produced by sporangia Sporangia clustered in sori singular = sorus) Usually small button-like dots on backs of fronds

three types of Gnetophytes

Welwitchia: monotypic Epherda Gnetum

Mosses

Widely distributed, esp. alpine, boreal, temperate, and tropical forests Able to live in very dry or very cold habitats Many can dry out entirely, then rehydrate

Pollination

Wind-blown pollen grains land on drops of fluid produced by the ovules on the ovulate scales (pollination droplet) when the water evaporates back into the micropyle (opening in ovule), the pollen grains go with it *follows movement of water* pollen grain germinates and produces a pollen tube for the sperm (mature gametophyte) to travel through ovule will develop into a seed integument (outer coating) will become the seed coat

Cool Plant Wollemia nobilis

Wollemi pines - found in a gorge in Australia in 1994 - previously only known from fossil record (rediscovered) - fewer than 100 in the wild - drops branches instead of leaves like other trees. branches are loosely connected to trunk which allows it to sustain drought and harsh conditions. - poorly adapted to Australia's dry climate

strobilus

a structure present on many land plant species consisting of sporangia-bearing structures densely aggregated along a stem. Strobili are often called cones, but many botanists restrict the use of the term cone to the woody seed strobili of conifers

Chlorophyta Cell Walls

absent cellulose or modifications

Cool Plant Heterosigma

actually moves around to avoid the plankton that eats it

Red Algae Habitats

attached to surfaces many are reef building calcium cell covering leads to habitat builders

Phaeophyceae Cell Walls

cellulose alginates

Red Algae Cell Walls

cellulose some with calcium carbonate

Red Algae Pigments

chlorophyll a phycobilins carotenoids (efficent light harvesting)

Chlorophyta Pigments

chlorophyll a & b carotenoids Food reserve: starch

Phaeophyceae (Brown Algae) Pigments

chlorophyll a and c fucoxanthins

sori

collection of sporangia (where spores are made) little spots on the backs of fern leaves

Fall color change in the USA vs Europe

color displays a tree's natural endurance in America and Asia, mountain ranges run north to south, allowing for easy migration of tree species when the ice sheets came from the poles. However, in Europe, the mountain ranges run east to west, forcing species to migrate OVER the ranges, which is much more difficult, resulting in lost species.

Four extant groups of Gymnosperms

conifers, cycads, gnetophytes, and ginkgo

Phaeophyceae Economic uses

directly consumed and used to dress wounds and treat burns Alginate is used in toothpaste, soaps, water/fire proofing, and treats acid reflux

Red Algae Economic Uses

directly consumed, agar agarose (dental impressions), carrageenan (thickening agent in foods), found to block transmittence of HIV and Herpes when used as lubricants

Bryophyte Gametophytes

dominant generation flattened (THALLOID) grow close upon the ground - absorption directly into photosynthetic tissue stemlike structures with thin, leaflike appendages usually only one cell thick close to the ground, anchored by rhizoids, long, tubular single cells (no tissues)

Vascular Plants

everything after Bryophytes Lycophytes, Monilophytes, Gymnosperms, Angiosperms

Land Plants

everything after Green Algae Bryophtyes, Lycophytes, Monilophytes, Gymnosperms, Angiosperms

Seed Plants

everything after Monilophytes Gymnosperms and Angiosperms

Lycopods

fern Two forms of reproduction: Sporophylls - normal Gemma - clones

dimorphic fronds

fertile and sterile stems bryophytes also do this

Chlorophyta (Green Algae)

fossil record: 1.5-2 BYA about 8,000 species marine, freshwater, and terrestrial attached to surfaces or planktonic

Seed Plants / Gymnosperms

heterospory produce seeds but not flowers or fruits pollen grains: male reproduction seeds exposed on surfaces of leaflike structures (sporophylls)

Photosynthetic Protist

historical term applied to organisms that contain chloroplasts and photosynthesize but are NOT plants

Fern life cycle

homospory then later heterospory

Bryophytes

hornworts, mosses, liverworts 500-400 million years ago Sporophyte dependent *Gametophyte dominant* no true leaves, direct absorption of water and minerals, and no lignified vascular tissue

Megasporangium

inside the ovule Megasporangium (2n, nucellus) produces megaspore (n). Megaspore grows into megagametophyte (n). Megagametophyte produces eggs all happens in one place and eggs are retained

Cool Plant Kelp

kelp forests are dominated by large photosynthetic protists their holdfasts are called "attachment structures" and are like roots, but DO NOT take up nutrients Bladders hold blades up in the water column

Lycophytes

lycopods, quillworts, and spikemosses fern allies

Conifer Reproduction

male gametophyte contained in pollen grain and female gametophyte are retained in leave where they are made

Chlorophyta Relationships

many form symbiotic relationships with other organisms (sea anemones, slugs, fungi, etc.)

Algae Growth Forms

micro and macroscopic single cells colonies of single cells filaments (cells lined up) multicellular blade

Lycophyets are the only land plants with

microphylls

Algae are very simple

no tissues, no complex structures, no vascular system

Cool Fern Iridescent fern

optical illusion: cells with very thin walls stacked to block intense sunlight photoprotection from sunlight

Cool Plant Fiddleheads

ostrich fern is the best direct consumption avoid bracken fern as it is carcinogenic

Cool Plant: Ginkgo

plant went extinct in the wild but was rediscovered in China at a Buddhist temple, where it was preserved for its medicinal purposes. Monotypic: one representative of the whole species Dioecy: male or female plant (not both) Anachronistic fruits entire lineage went extinct, but it is a very temperate plant

Microsporangium

pollen grain Microsporangium (2n) produces microspore (n). Microspore grows into microgametophyte (n). Microgametophyte produces sperm

Cool Plant Nori (Porphyra)

red algae cold water seaweed

Synapomorphy

shared derived characteristic

Chlorophyta Economic Uses

some direct consumption BIOFUELS

Sporangium

the place where spores are made

Red Algae Growth

unicellular, simple filaments, and complex filamentous aggregations

Ovule

where female gametophyte lives will contain the next generation (egg) after fertilization, the ovule becomes the seed with the 2n sporophyte (embryo) inside

Gnetophytes Hypothesis

widespread group in the Mesozoic period (250-65 mya) and are now mostly extinct long thought the sister group to the Angiosperms Hooker, 1863 "Gnetales are intermediate step between Gymnosperms and Angiosperms"