Chapter 18

By: Cody Crawford

18-1 ProtistWhat is a Protist?

• All protist are eukaryotes-they contain a nucleus & have organelles

• All protists vary in size

• Most protists need O2 (aerobic)- others don’t (anaerobic)

• Some are autotrophs; other are heterotrophs

• Some are sexual; others are asexual

Living Protists

• Autotrophic protists

• Ex)algae are photosynthetic autotrophs

• 30,000 species of algae- fresh/marine

• 30-40% of all photosynthesis on earth is performed by these protists

Single celled algae include

• Euglenophyta

• Pyrophyta

• Chrysophyta

Multicellular algae

• Chlorophyta

• Rhodophyta

• Phaeophyta

Heterotrophic protists

• EX)commonly known as protozoans-can be viewed with a light microscope

Reproduction of protists

• Euglenophyta reproduce asexually

• Gametophytes reproduce sexually

18-2 Fungi

• Fungi- heterotrophic eukaryotes that have cell walls

• Most fungi are multicellular

• The cell walls do not contain cellulose but instead contain chitin

Basic structures of a fungi

• Threadlike filament called a hypha-grows down into whatever the fungus is feeding on- forms a mass called the mycelium (secretes enzymes that breaks down compounds) when the conditions are right, parts of the mycelium may be organized into the fruiting body of what we call a mushroom

Four Phyla of Fungi

1. Zygomycota

2. Ascomycota

3. Basidiomycota

4. Deuteromycota

What They Are

• Zygomycetes-often called bread mold EX)black mold

• Ascomycetes-often called sac fungi 30,000 species of mildews,molds,& yeast this is the largest phylum of the kingdom fungi

• Basidiomycetes-includes the mushrooms EX)puffballs

• Deuteromycetes-sometimes called “imperfect fungi” EX) penicillium is good; athletes foot&jock itch –bad

More of what they are

• Lichens- greenish scalelike patches on tree trunk trunks

• They are a symbiotic partnership between a fungus and a photosynthetic algae

Reproduction of fungi

• Both sexually and asexually

18-3 muticellular plants

• Kingdom plantae

• All plants are multicellular, photosynthetic eukaryotes who cells are enclosed & supported by a cell wall made up of cellulose

• The majority of plants reproduce sexually but not all

Bryophytes

1. Include mosses,liverworts, hornworts, and peat mosses

2. Survive in wet climates

3. Grow not more than a few cm tall

4. Peat mosses grows almost totally under H20

Tracheophytes

1. Contain vascular tissues that transport H20 and nutrients

2. Grow much larger & have a wider range of habitats than the bryophytes

3. Other examples gymnosperms & angiosperm

4. Ferns is a simple tracheophyte

Gymnosperms 1. 1st seed bearing tracheophytes 2. EX)cycads,ginkgoes,& conifers3. They carry their seeds exposed to air in a cone

shaped structure 4. Seeds and reproductive structure that include a

developing plant and a food reserve are enclosed in a resistant outer covering

5. Most common is the conifers which are known for their cones & needle like leaves

-Cones produce & carry seeds -Often called evergreens

Angiosperms

1. These are food sources for humans & other animals

2. Reproduce & mature quicker than gymnosperms3. Divided into two groups- monocots & dicots4. Cotyledons-structure in seeds that contain food for

the developing plant5. Monocots-rice,wheat,corn,lilies,orchids,tulips,&

palms- containe one cotyledon6. Dicots- tomatoes,roses,maples,sunflowers-contain

two cotyledons

Structures of the Plant • Roots-anchor plants in soil; absorb H20 &

nutrients • Leaves-provide the surface area over which the

plant can capture sunlight for photosynthesis-Broader & flatter the leaf- the more

sunlight it captures

-this also allows for more H20 lost to evaporation

-to resolve this issue, plants have a waxy H20 proof covering on their leaves called a cuticle

• Cuticles are dotted with tiny openings called stomata (which allow for gas exchange)

Vascular tissues

• Xylem-carries H20 & dissolved in organic nutrients from the roots to the branches & leaves; cell walls are thick with cellulose; major sources of strength in woody plants

• Phloem- carries the products of photosynthesis from one part of a plant to another; the transport of these materials may be upward or downward

Stems

• Stems- hold leaves up to the sun and position leaf surfaces to capture as much light as possible

• Also conduct H20, nutrients, products of photosynthesis, & other materials through the plant by means of their vascular tissues

How do Plants Reproduce?

• All plant life cycles involve alternation of generations between sporophyte and gametophyte

• In mosses, the gametophyte is the longest part of the cycle

• In flowering plants, the sporophyte part of the cycle is much longer

Mosses

• Mosses- gametophyte generation consists of male and female structure called sperm and eggs

• The sperm must fertilize the egg to produce a zygote

• This zygote grows into the sporophyte -a slender stalk with a spore capsule on the end

-inside this capsule, meiosis produces spores -the spores are dispersed & produces

gametophyte plants

Pollen&Seeds

• Seed plants are members of the dominant sporopyte generation

• The gametophytes have been reduced to small clusters of a few cells that grow inside structures called: cones in gymnosperms and flowers in angiosperm

Pollen&Seeds (con’t)• The entire male gametophyte is contained in a tiny

structure called pollen • A pollen grain produces sperm & is carried by the

wind to eggs• Insects, beetles,birds,& bats also carry pollen to

eggs • Once pollen lands on the female egg part, a long

tube containing the sperm begins to grow down inside the flower until it reaches the eggs

• After fertilization, the egg grows into an embryo • The embryo becomes dormant inside a seed • A seed provides protection and food; waits for

germination