Download Plants & Fungi

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



Sepals
Petals
Stamens (male)



Anther - pollen
Filament
Carpel (female)




Stigma
Style
Ovary - fruit
Ovule-eggs- seeds
The flower
Figure 30.13 Flower-pollinator
relationships
(a) A flower pollinated by honeybees.
(b) A flower pollinated by hummingbirds.
This honeybee is harvesting pollen
The long, thin beak and tongue of this
and Nectar (a sugary solution secreted
rufous hummingbird enable the animal
by flower glands) from a Scottish
to probe flowers that secrete nectar
broom flower. The flower has a tripping
deep within floral tubes. Before the
Mechanism that arches the stamens
hummer leaves, anthers will dust its
over the bee and dusts it with pollen,
beak and head feathers with pollen.
some of which will rub off onto the
Many flowers that are pollinated by
stigma of the next flower the bee visits.
birds are red or pink, colors to which
bird eyes are especially sensitive.
(c) 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.
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 fungiMutualistic 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 without
mycorrhizae is
often stunted
Mycorrhizae
Pathogenic Fungi

Attack plants




Attack People – Mycosis




Rusts -red spores on multiple hosts
Smuts –yeast like fungi rot plant
Aflatoxins, Ergot –on rye.
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
stones
2. Foliose- leaf-like as
in picture
3. 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