Bio 126 Nature Study & Conservation

Plants & Fungi

Plants: Evolved from green algae Have evolved more terrestrial modes of

reproduction. Are the primary producers on land Determine how many animals can be

supported in an ecosystem Limited by water, sun, nutrients (like

Nitrogen), weather extremes, soil types,etc.

Green Algae at seashore

Green Algae Have aquatic (swimming) gamete = sperm

and egg Lack transport tissues - (like wood)

No Xylem – carries water No Phloem – carries sugar

No true roots or leaves Some can dry out at low tide

Green Algae gave rise to: Mosses and liverworts, which gave rise to: Ferns and related plant groups which gave

rise to: Conifers and related plant groups which

gave rise to: Angiosperms (flowering plants) which

have form two groups: Monocots Dicots

Mosses No hard parts (no xylem , no phloem) Still has sperm and eggs (needs a film of

water to reproduce) Disperse by spores: single plant cells that

can dry out, move in air currents Have no roots or leaves Many can dry out

Ferns and related groups Still have sperm and eggs Still disperse with spores Have Xylem, phloem

Can grow taller, like tree ferns Can pull water from deep in the soil

Gymnosperms - Conifers “naked” seeds – a protected embryo for

dispersal, no spores Pollen – male gamete, dry in air - wind Many have needles Some can tolerate very dry, cold conditions Have male and female cones

“pine cone” is female cone with seeds Cone size may be linked to seed size Protected, no water needed for fertilization

Angiosperms: Flowering plants Coevolved with pollinators

Flowers structure evolved to attract, work with pollinators

Seeds form inside a fruit Fruit coevolved with dispersal agents:

animals, wind

The flower

Sepals Petals Stamens (male)

Anther - pollen Filament

Carpel (female) Stigma Style Ovary - fruit Ovule-eggs- seeds

Figure 30.13 Flower-pollinator relationships

A flower pollinated by honeybees.This honeybee is harvesting pollen and Nectar (a sugary solution secreted by flower glands) from a Scottish broom flower. The flower has a tripping Mechanism that arches the stamens over the bee and dusts it with pollen, some of which will rub off onto the stigma of the next flower the bee visits.

(a) A flower pollinated by nocturnal animals. Some angiosperms, such as this cactus, depend mainly on nocturnal pollinators, including bats. Common adaptations of such plants include large, light-colored, highly fragrant flowers that nighttime pollinators can locate.

(c)A flower pollinated by hummingbirds. The long, thin beak and tongue of this rufous hummingbird enable the animalto probe flowers that secrete nectar deep within floral tubes. Before the hummer leaves, anthers will dust its beak and head feathers with pollen. Many flowers that are pollinated by birds are red or pink, colors to which bird eyes are especially sensitive.

(b)

Butterfly Flower

Butterfly Flower

Butterfly Flower

Hummingbird

Bee flower

Fungi

Fungal Characteristics:

Feed by Absorptive Nutrition Tubular cell shape, called Hyphae

Septate or aseptate hyphae Chitin cell walls Reproduce by making spores

Sexual & Asexual No sperm or egg

Nutrition and Habits Saprobes- decomposers

exoenzymes Parasitic fungi- Mutualistic Fungi-

Molds – rapidly growing, asexually reproducing fungi

Most also have non-mold sexual stages The mycelia of these fungi grow as

saprobes or parasites on a variety of substrates

Often breakdown simple sugars etc.

Yeasts- unicellular fungi growing in liquid substrates Form new cells by budding Some can sexually reproduce, many form asci Some can ferment sugar to alcohol

Mycorrhizae Mutualism of Tree root and

fungus. Gives tree water and minerals

(desert plants) and fungus gets carbohydrates.

Make most of your forest mushrooms

Plant growth withoutmycorrhizae is often stunted

Mycorrhizae

Pathogenic Fungi Attack plants

Rusts -red spores on multiple hosts Smuts –yeast like fungi rot plant Aflatoxins, Ergot –on rye.

Attack People – Mycosis Ringworm, athlete’s foot San Joaquin Valley Fever Yeast, lung infections

Attack insects, fish, etc.

Examples of fungal diseases of plants

(a) Corn smut on corn (b) Tar spot fungus on maple leaves (c) Ergots on rye

Lichens Symbiosis of

Phycobiont, algae / cyanobacteria Mycobiont - fungi.

Not individual organisms Primary colonizers of new land in

succession, and in tundra areas Soredia asexually reproduce lichen

Fungi often reproduce on their own.

Fig. 31.17

Three growth forms:1. Crustose – flat on

stones2. Foliose- leaf-like as

in picture3. Fruticose- upright

growing

Phycobiont in inner layers protected by fungi on top and bottom

(a) A fruticose (shrub-like) lichen

(b) A foliose (leaf-like) lichen (c) Crustose (crust-like) lichens