The Classification of Plants Plant Diversity The Classification of Plants

PLANT CHARACTERISTICS Slide # 3 PLANT CHARACTERISTICS Multicellular eukaryotes Photosynthetic autotrophs containing chloroplasts. Non-mobile (fixed to one spot) Cell walls made of cellulose Responds to environment and grows through the use of hormones

Plants Make the The Move to Land Slide # 4 Plants Make the The Move to Land The ancestors of plants were multicellular green algae. They were completely immersed in water & dissolved minerals. To move onto land, plants had to solve these problems: How to get chemical resources (water, minerals, oxygen, and carbon dioxide) separated into air and soil How to transport resources within the plant. How to prevent from drying out How to reproduce without water

Some Adaptations (solutions)- Slide # 5 Some Adaptations (solutions)- Have body parts extending into both air and soil Develop a vascular system to transport resources in plant (xylem & phloem) Have a protective layer – cuticle (waxy outer layer) to keep from drying out Specialized structures for reproduction including spores & seeds that do not dry out

Plants are classified based on whether or not they have Slide # 6 Plants are classified based on whether or not they have Vascular System (transport) Seeds Flowers (enclosed seeds)

Plants Has NO Vascular Tissue Has Vascular Tissue Bryophytes Slide # 7 Concept Map: Plants are divided 1st by whether or not they have a vascular system. Plants Has NO Vascular Tissue Has Vascular Tissue Bryophytes Tracheophytes

Bryophytes -NONVASCULAR Slide # 8 Most primitive plants Found in moist, shady areas b/c no true roots NO vascular (transport) system Reproduces using spores 5. example: Mosses

Typical Moss Plant (most common bryophyte) Slide # 9 Spores form inside the capsule. Notice the problem of nutrient separation into air and soil is solved with underground and above ground parts. (Although NO TRUE roots, stems or leaves are present)

Tracheophytes -Vascular Plants- Slide # 10 Contains two types of specialized vascular tissues for transport within the plant: Xylem- transports H20 up from roots. Phloem- transports food made during photosynthesis and nutrients to where they are needed in the plant. Presence of a vascular system allowed plants to become tall. Has specialized organs: roots, stems, and leaves.

Tracheophytes Seeded Seedless Ferns use spores Slide # 11 Tracheophytes are divided into two groups by whether or not they reproduce with seeds. Tracheophytes Seeded Seedless Ferns use spores

There are 11,000 species of ferns. Slide # 12 The Fern - a seedless vascular plant There are 11,000 species of ferns. Contain a vascular system. Reproduce using spores, Not seeds. Sori

Seed-Bearing Tracheophytes Slide # 13 ADVANTAGE: Developed reproductive strategies that do not need water: Seed contains A fully developed embryo Food supply for embryo A water-proof seed coat to keep from drying out Sperm transferred in water-proof pollen through pollination by wind or animals. Developed seed-bearing structures: Cones and Flowers

Tracheophytes Seeded Seedless The two Seeded Tracheophyte groups are divided by whether or not they have enclosed seeds -protected inside a fruit or if seeds are exposed to the environment. Tracheophytes Seeded Seedless Ferns use spores Gymnosperms Angiosperms “naked” or exposed seeds Flowers produce fruit w/ enclosed seeds

Gymnosperms- “naked seed” Slide # 15 Ginkgo, Conifer (pine, spruce, firs, cedars, sequoias, redwoods, junipers, yews, & cypress trees) Sago Palm Ginkgo Ginkgo

Gymnosperms-Conifers Sequoia Slide # 16 Gymnosperms-Conifers Most common gymnosperms are Conifers Conifers have leaves called needles or scales (have a reduced surface area and thick waxy coat on the needle to reduce water loss and prevents freezing.) Juniper Pine

Angiosperms- “enclosed seeds” Slide # 18 These are flowering plants the encourage direct and efficient pollen transfer (smell, color and offering nectar) Flowers contain ovaries, which is where eggs/seeds are produced. A fruit is the pollinated ovary containing mature seeds.

Fruit can aid in dispersal of seed to reduce competition with parent plant. Slide # 19 Winged fruit – glides to new location (maple fruit) Floating fruit – can float to new locations (coconut) Fleshy fruit - sweet bright colored fruit have seeds that survive the digestive system of animals that eat the fruit (apple) Spiny fruit- Velcro like projections attach to the fur of animals (cockleburs) Maple seeds: Winged fruit Burdock: Spiny fruit

Flower Anatomy http://vimeo.com/1594037?pg=embed&sec=1594037 Flower Structure Pollination Fertilisation Seed Dispersal Germination Test

Fill in Your Flower! stigma anther style stamen carpel filament ovary ovule petal sepal receptacle peduncle Flower Structure Pollination Fertilisation Seed Dispersal Germination Test

Pollination is the transfer of pollen from the anther to the stigma This is an example of cross-pollination as the pollen travels from one flower to a different flower. This is desirable in plants as it promotes variation. Flower Structure Pollination Fertilisation Seed Dispersal Germination Test

Self-pollination occurs when pollen falls from the anther onto the stigma of the same flower Self-pollination is not desirable as it reduces variation Flower Structure Pollination Fertilisation Seed Dispersal Germination Test

Flowers will prevent self-pollination by either having stigma above stamen or… Flower Structure Pollination Fertilisation Seed Dispersal Germination Test

…by having stamen and stigma mature at different times. Flower Structure Pollination Fertilisation Seed Dispersal Germination Test

Once pollination occurs a tube grows from the pollen grain down through the style to the ovule stigma style carpel Note: Petals not shown in order to simplify diagram ovary ovule Flower Structure Pollination Fruit Development Seed Dispersal Germination Test

Fertilisation occurs when the male gamete fuses with the ovule (the female gamete) Flower Structure Pollination Fruit Development Seed Dispersal Germination Test

Angiosperms can be categorized as monocots and dicots.

After fertilisation the petals, stamen and sepals fall off. The ovule turns into a seed, the fertilised egg inside develops into an embryo plant. Cotyledon: Food store Testa: tough seed coat Plumule: Embryo shoot Micropyle: Hole made by pollen tube Embryo plant Radicle: Embryo root Flower Structure Pollination Fruit Development Seed Dispersal Germination Test

Water leaves the seed, it dehydrates and becomes dormant because metabolic reactions stop. The ovary develops to become a fruit. Fleshy wall of the ovary (yes, you are eating an adapted ovary when you crunch into an apple! seed Flower Structure Pollination Fruit Development Seed Dispersal Germination Test

Quiz Time What did plants have to overcome to live on land? What is the most primitive division of plants because they have no vascular system? What is the most common example in this division and how do they reproduce? Why are mosses so small? What is the division of plants that contain a vascular system? What did a vascular system do for plants size-wise? How are mosses and ferns different? How are mosses and ferns alike?

Quiz Time How are Tracheophytes different from bryophytes? How are tracheophytes divided? What are the advantages of seeds over spores? What other advantages did seed-bearing plants have over spore-bearing plants? What are the two divisions of the seed-bearing tracheophytes?

Quiz Time What does the term Gymnosperm mean? What are the most common of the Gymnosperms? What is the evolutionary importance of needles? What structures do conifers use to reproduce? Were are seeds located in the cone? Even though wind-dispersal of pollen is inefficient, what did it allow plants to overcome?