Plants, Fungi, and the Move onto Land Ch. 16

Kingdoms There are 6 Kingdoms of Life: 1) Kingdom Archaea: Prokaryotic extremophiles 2) Kingdom Monera: All other prokaryotes 3) Kingdom Protista: single celled Eukaryotic organisms 4) Kingdom Fungi: fungus (absorptive) 5) Kingdom Plantae: plants (photosynthetic autotrophs) 6) Kingdom Animalia: animals (heterotrophs)

Kingdom Plantae and Kingdom Fungi We will deal with two “Kingdoms” in this chapter: Plantae and Fungi We’ll deal with the evolution and diversity of plants; and also the diversity of fungi

Kingdom Plantae

Overview of land plant evolution      There are our main groups of land plants Bryophytes Pteridophytes Gymnosperms Angiosperms                        

Four main groups of land plants 1.  Bryophytes – liverworts, hornworts, mosses                                     - Bryophytes have no vascular tissues.   -Bryophytes live in damp/moist environments and are small so they don’t need vascular tissue. They are sometimes called “non-vascular plants”.

Four main groups of land plants The rest three groups are all vascular plants.  Vascular plants have cells that are joined to produce tubes that transport water and nutrients throughout the plant.  

Except for bryophytes, land plants have vascular tissue in roots, stems, and leaves.                                                 - Xylem consists of dead cells that carry water and nutrients from roots to the rest of the plant. - Phloem consists of living cells that distribute sugars and amino acids throughout the plant.

The vascular plants are, in order of their evolution:

Four main groups of land plants 2.  Pteridophytes – ferns, horsetails, lycophytes     a.  seedless plants, have a vascular system

Four main groups of land plants 3.  Gymnosperms – conifers, ginkgo, cycads, gnetopsida      a.  early seed plants      b.  produce “naked seeds”

Four main groups of land plants 4.  Angiosperms – flowering plants       a.  seeds protected by growing in ovaries       b.  majority of modern plants are in this group

BRYOPHYTES 1. Bryophytes – liverworts, hornworts, mosses                                     - Bryophytes have no vascular tissues.   -Bryophytes live in damp/moist environments and are small so they don’t need vascular tissue. They are sometimes called “non-vascular plants”.

Bryophytes

  Ecological and economic benefits of bryophytes                         1.  Bryophytes were the world’s only plants for 100 million years.   2.  Peat bogs are made mostly of moss called sphagnum.  They contain 400 billion tons of carbon and cut down the amount of greenhouse gases. Peat is harvested, dried, and used as a fuel. 3.  Sphagnum is harvested for use as a soil conditioner and plant packing material.

Sphagnum, or peat moss

PTERIDOPHYTES Pteridophytes – ferns, horsetails, lycophytes     a.  seedless plants, have a vascular system

Figure 29.24b Fern sporophyll, a leaf specialized for spore production

Importance of Pteridophytes                         1.  Dominant plants in Carboniferous period   2.  Extensive beds of coal from these plants

Artist’s conception of a Carboniferous forest based on fossil evidence

The Evolution of Seed Plants: Gymnosperms and Angiosperms

SEEDS Seeds became an important means of dispersal.                         Seeds are resistant to environmental stress, and are multi-cellular complex structures that consist of a sporophyte embryo, a food supply, and a protective coat.   The embryo develops from the fertilized egg (derived from a spore) retained within the sporangium. The sperm (derived from a spore) is carried (produced by) a pollen grain released from a sporangium.

Pollen (with sperm cells) eliminated the liquid-water requirement for fertilization.                         Pollen travels by air or on animals.  It eliminates the need for water to be present during fertilization.

GYMNOSPERMS

Gymnosperms Gymnosperms are vascular plants that bear naked seeds – seeds not enclosed in specialized chambers.  Mesozoic era was the age of gymnosperms Gymnosperms were the most common plants during the Mesozoic era (the age of dinosaurs).   Four phyla of extant gymnosperms – Phylum Ginkgophyta: e.g., Ginkgo biloba. – Phylum Cycadophyta: e.g., cycads. – Phylum Gnetophyta: e.g., ephedra – Phylum Coniferophyta: e.g., pines, firs, spruces

Winged seed of a White Pine (Pinus strobus)

ANGIOSPERMS

Angiosperms are flowering plants that form seeds inside a protective chamber called an ovary. Examples:  Monocots: Orchids, lilies, grasses, palms, bamboo (Eu)dicots: Daisies, maples, snapdragon, pea, oaks

Angiosperms (Flowering Plants) Systematists are identifying angiosperm clades. Originally, only:                         Monocots are angiosperms that possess one embryonic seed leaf (cotyledon).   Dicots are angiosperms that possess two embryonic seed leaves (cotyledons). However, angiosperms have recently been divided into new taxonomic groups.

A comparison of monocots and dicots

FLOWERS The flower is the defining reproductive adaptation of angiosperms                         Flowers are made up of four types of modified leaves à sepals, petals, stamens, and carpels.                                     a.  Stamens are the male reproductive organs that produce microspores.   b.  Carpels are female reproductive organs that produce megaspores.

The structure of a flower.

A fruit is a mature ovary                                     Protect dormant seeds.   Fruit aids in seed dispersal.                      - Wind dispersal                      - Attachment and transportation                      - Consumption – berries contain seeds to be passed in feces

Fruit adaptations that enhance seed dispersal

Plants and Human Welfare Agriculture is almost totally dependent on angiosperms.   Plant diversity is a non-renewable resource.                         Many medicines are obtained from plant materials.

A sampling of medicines derived from plants

KINGDOM FUNGI

Kingdom Fungi Fungi, like plants and animals, are all around us!

Fungi are eukaryotic, mostly multicellular, decomposers deriving their nutrition from the absorption of nonliving, decaying organisms Some pathogenic and parasitic fungi acquire nutrition from living hosts

Fungal structures The bodies of most fungi are constructed as hyphae=minute threads composed of tubular walls surrounding plasma membranes and cytoplasm These hyphae form a mat of mycelium, the feeding network of fungi 10 cubic centimeters (4 cubic inches) of soil may contain as much as a kilometer (3/4 mile) hyphae

Fungal reproduction Fungi reproduce either sexually or asexually by releasing spores carried by water or wind These spores are numerous! When they land on a moist surface with food availability, they then grow

Division Basidiomycota: Reproduce via spores called basidia in a club-like structure called a basidium

Division Ascomycota: Known as sac fungi Produce spores in a sac called an ascus 75% of all described fungi

Lichen: this is a symbiotic relationship between algae and fungus