SDSU Bio 204 Exam 2 (Ekdale)

Unikonta

Supergroup that includes fungi, animals and some protists (Two Clades: Amoebozoa and Opisthokonta)

Amoebozoa

Clade, consists of true amobas

Opisthokonta

Clade that includes fungi, animals, and related protists

Fungi Synapomorphies

- Feed through absorptive nutrition (decomposers)

- Cell walls with chitin

- Mostly multicellular, some unicellular (yeast)

- Most are saprobes

Absorptive Nutrition in Fungi

They secrete digestive enzymes to break down food, then absorb digested food into their cells

Saprobes

Organisms that live off dead or decaying organic material (Ex: Fungi)

Ecological Importance of Fungi

- Decomposers

- Mutualistic Symbionts (microrrhizae)

- Parasites/pathogens

- Various economic uses

Mycorrhizae

Fungus that grows in association with the roots of a plant, provide water and nutrient absorption (symbiotic)

Endophytes

Harmless fungi inside plant parts, they create toxins to deter herbivores and defend against pathogens

Haustoria

The appendages of parasitic fungi

Hyphae

Filamentous structures that compose a fungus

Mycellium

Mass of hyphae that form the body of the fungus

Septate Hyphae

Hyphae that are divided

Coenoncyte Hyphae

Hyphae that are undivided

Asexual Reproduction in Fungi

Mycelium produces spores that are released, germinate, and form new mycelia

Sexual Reproduction in Fungi

1. Plasmogamy

2. Heterokaryotic

3. Karyogamy

Plasmogamy

fusion of cytoplasm between two mycelia

Heterokaryotic

stage containing two or more haploid nuclei following plasmogamy

Karyogamy

fusion of nuclei to form diploid zygote

5 Clades of Fungi

1. Chytridomycota

2. Zygomycota

3. Glomeromycota

4. Ascomycota

5. Basidomycota

Chytridomycota

Possess flagellated spores, mostly aquatic saprobes or parasites

Zygomycota

- Sporangia in asexual fungi

-Zygosporangia in sexual fungi

-Coenocytic hyphae

- Some form mycorrhizae

Glameromycota

- Mostly endophytes

- Arbuscular mycorrhizae that penetrate root cells

Ascomycota

- Sac fungi and yeast

- Ascus (sac that contains ascospores)

- Ascocarp

- Conidia

Ascocarp

Fruiting body that creates and releases ascospores during the sexual stage of ascomycota

Lichens

- Fungi with a photosynthetic symbiont

- Green algae or cyanobacteria

- Sensitive to air pollution

- Most are ascomycetes

Basidomycota

- Includes mushrooms, shelf fungi, puffballs, jelly fungi

- Basidium (sexual structures)

- Decomposers, pathogens, mycorrhizae and mushrooms

Basidium

- Site of meiosis in basidomycota

- Basidiospores extruded to the outside from the basidiocarp

Archaeplastida

Includes red algae (protists), green algae (chlorophytes, charophyceans), and land plants (embryophytes)

Green Algae

- Chlorophytes & charophytes

- contribute to biofuels

- Both unicellular and multicellular

Chloroplasts

- Stacks (grana) of thylakoids contain chlorophyll a & b

- Store starch

Chlorophyll a & b

Pigments that absorb light for photosynthesis

Terrestrial Adaptations of Plants

- Apical meristems

- Cuticle

- Thick spore walls

- Gametangia

- Dependent embryos

Apical Meristems

Localized regions of plant growth (shoot & stem & root)

Cuticle

Waxy covering to prevent desiccation (drying out)

Thick Spore Walls

Prevent desiccation

Gametangia

Cases that enclose gametes and prevent desiccation

Antheridium

- male reproductive organ of a gametophyte

- produces sperm (haploid = 1n)

- Protects against water loss

Archegonium

- Female reproductive organ of gametophyte

- Produces egg (haploid = 1n)

- protects against water loss

Dependent embryos

Young sporophytes contained within a protective structure

Bryophytes

- Liverworts, mosses and hornworts

- Gametophyte dominant

- Motile (flagellated) Sperm

- No vascular tissue

Hornworts

- Sister taxi of land plants

- Both share stomata

Stomata

Function in gas exchange (CO2 in, O2 out)

Vascular tissue

Duct system for conducting fluids and nutrients; allows for increased height

Tracheophyta

- Sporophyte dominant

- Lignified vascular tissue (xylem & phloem)

- organ systems

Xylem

Conducts most of water and minerals; includes tube-shaped cells called tacheids

Phloem

Cells arranged into tubes to distribute sugars, amino acids and other products of photosynthesis

Lignin

Provide structural support for xylem

Leaves

Organs that increase the surface area of vascular plants and capture more solar energy

Microphylls

Leaves with a single vein

Megaphylls

Leaves with a highly branched vascular system

Sporophylls

Modified leaves with sporangia

Sori

Clusters of sporangia on undersides of sporophylls

Strobli

Cone-like structures formed from groups of sporophylls

Roots

- Organs that anchor vascular plants

- Enable plants to absorb water and nutrients from the soil

- Evolved from subterranean stems

Seedless Vascular Plants

- Formed the first forests

-contributed to global cooling

- Eventually became coal

Seed Plants (Spermatophyta)

- Seeds

- Highly reduced gametophyte

- Heterospory

- Pollen & ovules

Seeds

- Embryo and nutrients surrounded by a protective coat

- Protection, nutrition, dispersion and dormancy

Heterosporty

Evolution of two types of spores (microspores and megaspores)

Microspores

Male spores

Megaspores

Female spores

Pollen

Sperm, derived from microspores

Ovule

Consists of a megasporangium, megaspore, and one or more integuments

Angiosperms

- Flowering plants

- Largest group of land plants

- Flowers, fruits, carpel and double fertilization

Floral Organs

- Sepals

- Petals

- Stamens

- Carpels

Sepals (flowers)

Enclose the flower

Petals (flowers)

Attract pollinators

Stamens (flowers)

Produce pollen (male)

Carpels (flowers)

- Produce ovules (female)

- Ovary at the base and a style leading to a stigma where pollen is received

Filament (flowers)

A stamen with a sac called anther where pollen is produced

Angiosperm Life Cycle

1. Pollen grain germinates in a pollen tube, sperm enters through the micropyle

2. Double fertilization, two sperm enter female gametophyte

3. Fertilization, second sperm develops food storing endosperm

4. Tripoli endosperm nourishes the embryo

5. Double fertilization creates seeds, ovary develops into fruit

4 Fruit Types

- Simple

- Aggregate

- Multiple

-Accessory

Simple Fruit

Develop from a single or several fused carpels (peas, grapes, etc.)

Fruits

Mature ovaries

Aggregate Fruit

Result from a single flower with multiple separate carpels (strawberries, raspberries, etc.)

Multiple Fruit

Develop from a group of flowers (figs, pineapples)

Accessory Fruit

Contain other floral parts in addition to ovaries (pears, apples)

Two Groups of Angiosperms

- Monocots

-Eudicots

Monocots

- Palms, orchids, grasses

- One Cotyledon

- Parallel leaves

- Scattered vascular tissue

- Fibrous root systems

-Pollen grain with one opening

-Floral organs in 3s

Eudicots

- Most angiosperms (roses, daisies, oaks)

- two cotyledons

- netlike veins

- Vascular tissue in rings

- Taproot (main root)

- Pollen grain with 3 openings

- Floral organs in 4s and 5s

3 Organs of Plants

1. Roots

2. Stems

3. Leaves

Root System

- Anchors plant

- Absorbs/stores nutrients

Root Hairs

Where absorption of water and minerals occur; increased surface area

Stem

Organ consisting of alternating systems of nodes (where leaves are attached)

Leaf

- Main photosynthetic organ of most vascular plants

- Flattened blade and petiole (stalk)

Meristems

Perpetually embryonic tissue that allow for indeterminate growth

Apical Meristems

- Elongated shoots and roots through primary growth

- Located near tips of roots and shoots

Later Meristems

In woody plants, increase thickness through secondary growth

Primary Growth

- Produces primary plant body (root and shot system/apical meristems)

Root Cap

Covers root tip and protects apical meristem

Shoot Apical Meristem

Dome-shaped mass of dividing cells at the shoot tip

Leaf Primordial

Where leaves develop along the side of the apical meristem

Auxiliary Buds

Develop from meristematic cells at the bases of the leaf primordia

Vascular Cambrium

- Adds layer of vascular tissue called secondary xylem (wood) and secondary phloem

- one cell layer thick

Pathogen-associated Molecular Patterns (PAMPs)

Molecular sequences that are specific to certain pathogens

Cork Cambrium

replaces the epidermis with periderm (thicker & tougher)

Epidermis

Plant's first line of defense against infection

Effectors

Pathogen-encoded proteins that cripple a plant's immune system

Hypersensitive Response

- Causes cell and tissue death near the infection site

- Induces production of enzymes that attack the pathogen

- Stimulates changes in the cell wall that confine the pathogen

Systematic Acquired Resistance

- Long term response

- systematic expression of defense genes

- Production of salicylic acid triggers defense system to respond quickly