Fungi and Plant Diversity: Chapters 24–26

What is the common ancestor of all fungi?

Multicellular organisms

When did fungi first appear?

Approximately 470 million years ago

What nutritional mode do fungi use?

Absorptive heterotrophy

What do fungi secrete to digest complex organic polymers?

Hydrolytic enzymes (hydrolases)

What is the composition of fungal cell walls?

Chitin, a nitrogen-containing polysaccharide

What are the fundamental structural units of fungi?

Hyphae

What is mycelium?

An interwoven mass of hyphae forming a feeding network

What are aerial hyphae?

Specialized multicellular reproductive structures elevated for spore dispersal

What is the role of haustoria in fungi?

They penetrate host tissues to absorb nutrients

What are mycorrhizae?

Specialized hyphal connections formed with plant roots

What are the two main cellular forms of fungi?

Multicellular (mushrooms and molds) and unicellular (yeasts)

How do fungi primarily reproduce?

Asexually via spores or sexually via fruiting bodies

What is the ecological role of fungi as decomposers?

They break down complex organic matter and recycle nutrients

What is a mutualistic relationship involving fungi?

Mycorrhizae, where fungi supply minerals to plants and receive nutrients in return

What are endophytes?

Fungi living inside plant tissues that synthesize compounds to deter herbivores

What is a lichen?

A symbiotic association between a fungus and a photosynthetic partner

What are some examples of plant pathogens caused by fungi?

Chestnut blight, wheat rust, and corn smut

What are mycoses?

Fungal infections in animals, including superficial and systemic infections

How are fungi used in food production?

Direct consumption of mushrooms and fermentation processes

What role do yeasts play in fermentation?

They ferment sugars into alcohol and CO2 for baking and brewing

What is a key model organism for eukaryotic cell biology?

Saccharomyces cerevisiae (baker's yeast)

What important pharmaceutical is derived from fungi?

Penicillin, an antibiotic

What are decomposers?

Organisms that break down organic material, recycling inorganic nutrients.

What is the role of mutualists in ecosystems?

They absorb nutrients from a host while providing benefits to the host.

What defines parasites in relation to their hosts?

Parasites absorb nutrients from the host but do not provide any benefits.

What is the effect of decomposers on soil?

They enhance soil fertility and plant growth while preventing waste buildup.

What is a positive effect of mutualism?

Both parties benefit, enhancing survival, growth, and reproduction.

What is a negative effect of parasitism?

Parasites can harm their hosts but help regulate population sizes in ecosystems.

Give an example of a decomposer.

Mushrooms, molds, and yeasts.

What is an example of a parasite?

Ringworm (fungal skin infection) or Zombie Brain Fungus (Cordyceps).

What is the first step in the fungal life cycle?

Spores germinate into a new mycelium upon landing in a moist, nutrient-rich location.

What is plasmogamy in fungal reproduction?

The fusion of cytoplasm from two compatible hyphae without immediate nuclear fusion.

What occurs during the heterokaryon stage?

The mycelium contains distinct, unfused haploid nuclei from both parents.

What is karyogamy?

The fusion of haploid nuclei to form a temporary diploid zygote.

What is the result of meiosis in the fungal life cycle?

It generates genetically unique haploid spores.

How do filamentous fungi reproduce asexually?

They produce haploid spores via mitosis.

What is the role of pheromone signaling in fungi?

It directs compatible haploid mycelia to grow toward each other for reproduction.

What is the significance of the heterokaryotic stage?

It allows for genetic diversity as distinct haploid nuclei from both parents coexist.

What are the steps of asexual reproduction in fungi?

Haploid mycelium grows, spore-producing structures develop, and spores disperse.

What is the role of Chytrids?

Primarily aquatic fungi with unique flagellated spores for motility.

What is an example of a Zygomycete?

Rhizopus stolonifer (black bread mold).

What do Glomeromycetes do?

They form mycorrhizae, helping plants access nutrients.

What is a significant role of Ascomycetes?

They are decomposers and are used medically, such as in the production of antibiotics.

What are Basidiomycetes known for?

They are decomposers and forest recyclers, including edible mushrooms.

What is the key derived trait that defines the supergroup Archaeplastida?

Chloroplasts from Primary Endosymbiosis

What are the main groups included in the supergroup Archaeplastida?

Red Algae, Chlorophytes, Charophytes, and Land Plants

What are the derived traits of Verdiplante (green plants)?

Cellulose cell walls providing structural support

What are the two main groups of Streptophytes?

Charophytes and Land Plants

What derived trait did Charophytes develop for survival in shallow ponds?

Sporopollenin, a durable waterproof coating for zygotes/spores

What is the significance of multicellular gametangia in non-vascular plants?

They are specialized reproductive organs for producing eggs and sperm.

What are the two phases of the alternation of generations in plants?

Haploid gametophyte phase and diploid sporophyte phase

What adaptations did non-vascular plants develop for life on land?

Multicellular gametangia, apical meristems, cuticle, and stomata

What is the role of stomata in plants?

They manage gas exchange and water loss

What defines non-vascular plants?

They lack internal plumbing (vascular tissue) and rely on diffusion and osmosis.

What is the life cycle preference of mosses?

They prefer the haploid gametophyte stage as their main, visible life phase.

What are the derived traits of ferns?

Vascular tissue reinforced with lignin, roots, leaves, and sporophylls

What is the significance of lignin in seedless vascular plants?

It enables tall growth by reinforcing water-conducting cells.

What are the two major groups of seed plants?

Gymnosperms and Angiosperms

What is a key derived trait of gymnosperms?

They have 'naked seeds' that are not enclosed in a chamber.

How do seed plants cut ties with standing water?

By inventing pollen and seeds, which are airborne sperm carriers and embryos with a food supply.

What is the main characteristic of angiosperms?

They have 'container seeds' enclosed in fruits.

What is the role of roots in vascular plants?

They absorb water and nutrients from the soil and anchor the plants.

What are sporophylls in ferns?

Modified leaves that contain sporangia, the spore-producing organs.

What is the significance of apical meristems in plants?

They allow the tips of the plant to grow towards sunlight and soil nutrients.

What is the importance of mosses in ecosystems?

They can colonize bare soil and help retain nitrogen.

What is the evolutionary significance of the transition from water to land for plants?

It led to the development of key adaptations for survival outside of aquatic environments.

What type of environment do non-vascular plants require for reproduction?

A moist environment, as their sperm need a film of water to swim to the egg.

What are the two phases in the alternation of generations?

Sporophyte phase (2n) and gametophyte phase (n)

What is the role of cuticle in land plants?

It prevents water loss and shields against microbes.

What type of plants are enclosed in fruit?

Flowering plants (angiosperms)

What evolutionary strategy do flowering plants use to recruit pollinators?

They added flowers to attract pollinators like insects.

Why are flowering plants considered the most dominant type of plant?

Their evolutionary strategy of enclosing seeds in fruits and recruiting pollinators has made them widespread and successful.

What is the significance of flowers in flowering plants?

Flowers are used to recruit pollinators for reproduction.

What is the lifestyle adaptation of flowering plants?

They have evolved to enclose seeds within fruits.

What is the first stage in the sequence of plant evolution?

Red algae

What type of plants are considered non-vascular?

Bryophytes

Which group of plants are known for having naked seeds?

Gymnosperms

What are angiosperms known for?

Flowering plants

What is the primary endosymbiosis of cyanobacteria associated with?

Red algae

What derived trait is unique to charophytes?

Flagellated sperm

What adaptations do non-vascular plants have for land?

Apical meristems, stomata, cuticle

What is the dominant generation in ferns?

Sporophyte

What is the process of alternation of generations?

Sporophyte (2n) → Meiosis → Spores (n) → Mitosis → Gametophyte (n) → Mitosis → Gametes (n) → Fertilization → Zygote (2n) → Mitosis → Sporophyte (2n)

What is the sequence of water transport in plants?

Roots → Stem → Leaves

What is the process of sugar transport in plants?

Multidirectional bulk flow from source cells (leaves) to sink cells (roots, fruits, growth tips)

What are the components of a seed?

Embryo, nutrients, protective coat

What is heterospory?

The production of two distinct spore types: megaspore and microspore

What is the significance of pollen in seed plants?

Facilitates sperm dispersal and reproduction in dry habitats

What are the derived traits of angiosperms?

Flowers, fruits, double fertilization

What role do flowers play in angiosperms?

Specialized structures for sexual reproduction

What is double fertilization in angiosperms?

One sperm fertilizes the egg, and another sperm fuses with two nuclei in the central cell to form a triploid endosperm

What is the function of the endosperm in angiosperms?

Nourishes the developing embryo

What are the four concentric layers of a flower?

Petals, stamens, carpels, sepals

How do angiosperms primarily disperse their seeds?

Via wind, water, and animals

What is the significance of the triploid (3n) cell in angiosperms?

It develops into the endosperm, which nourishes the embryo

What adaptations do gymnosperms have for reproduction?

Naked seeds

What are the main characteristics of seed plants?

Seeds, gametophyte, heterospory, pollen