- An Overview of Plants Characteristics: Range in size Have roots Microscopic water ferns to giant sequoia trees Have roots Have cell walls All plants need water Some plants cannot live unless they are submerged in freshwater or saltwater. Not all plants live only on land All plants are many-celled, and most contain green pigment called chlorophyll.

You notice green scum floating on the surface of a pond You notice green scum floating on the surface of a pond. How can you tell whether these organisms are plants? Answer? Examine them under the microscope. If they are many-celled and have chloroplasts, cell walls, and nuclei, they are plants!

Scientists think that plants evolved directly from green algae. 1st plants on land could only survive in damp areas. Oldest fossil plants are about 420 million yrs old. Pine trees existed 350 million yrs ago Flowering plants did not exist until 120 million yrs ago. Their exact origin is unknown

Adaptations to Land Plants that live on land need adaptations to help them conserve water. Cuticle- waxy, protective layer on leaves of plants Slows the loss of water Cellulose- an organic compound found in plant cell walls Found in cell walls to provide structure and support Chemical compound that forms tangled fibers in the cell walls of plants.

Classification of Plants Vascular or Nonvascular?? Vascular Plants Plants that have tube-like structures for transporting substances. Have vessels to transport water and nutrients Why would vascular tissue be an advantage to plants adapting to life on land? Answer: Vascular tissue carries water, minerals, and nutrients throughout the plant so it can exist away from water Nonvascular Plants Do not have these tube-like structures and use other ways to move water and substances. Contain spores, rhizoids, and cell walls.

Each cell absorbs water and nutrients on its own. Examples of Vascular Plants Fern Horsetail Pine Tree Examples of Nonvascular Plants Mosses Liverworts Hornworts Algae How do the cells of nonvascular plants get water and nutrients if they do not have vessels? Answer: Each cell absorbs water and nutrients on its own.

Seedless Nonvascular Plants Mosses- a seedless, rootless plant with leaf-like growths. Grow on tree trunks and rocks or the ground Found in damp areas, some live in deserts Liverworts- means “herb for liver” 9th century thought to be useful in treating liver diseases. Rootless with flattened bodies Hornworts- flattened body Spore-producing structure looks like horns of cattle

Nonvascular Plants + Environment Mosses and liverworts can grow in soils where other plants can not grow. Spores of mosses and liverworts are carried by the wind. Pioneer species The first to grow in a new or disturbed areas. Mosses and liverworts that are among the first plants to inhabit a new environment are called pioneer species. Liverworts and mosses are the first plants to grow in new environments.

Seedless Vascular Plants Ferns, ground pines, spike mosses, and horsetails. Ferns are the most abundant of the seedless vascular plants. Have vascular tissue Have stems, leaves, and roots Produce spores Club Mosses Needle-like leaves Horsetails Stem is jointed and has a hollow center surrounded by a ring of vascular tissue

Importance of Seedless Plants As plant materials die and build up they are compacted and compressed and eventually turn into coal. Ancient seedless plants compacted and eventually turned into the coal we use today. Similar process today, takes place in bogs Bogs- poorly drained areas with spongy, wet ground that is comprised mainly of dead and decaying plants Peat- remains of sphagnum moss Peat is actually the earliest stage of coal.

Seed Plants Have leaves, stems, roots and vascular tissue 2 major classifications of seed plants Gymnosperms and angiosperms Leaves Upper and lower surface is epidermis Organs of the plant where the food-making process occurs (photosynthesis) Major function- make food Stomata- small pores on leaf surface allowing carbon dioxide in Each stoma is surrounded by two guard cells that open and close it

Stems Roots Palisade layer Just below the upper epidermis Closely packed cells under the epidermis of leaves contains chloroplasts. Spongy layer- loosely arranged cell layer in the leaf Stems Moving materials between leaves and roots Stores food and water Supporting the plant Roots Anchor the plant Absorb water Store food

Vascular tissue Xylem- vessels that transport substances from the roots to other parts of the plant Phloem- vessels that move food from leaves to other plant parts Cambium- tissue that produces new xylem and phloem cells

Gymnosperms Vascular plants that produce seeds that are not protected by fruit “naked seed” DO NOT have flowers Ex. Ginkgoes, conifers, cycads All conifers produce male and female cones Reproductive structure The oldest trees alive are gymnosperms

Angiosperm Vascular plant that flowers and produces fruits with one or more seeds. Have a wide variety of flowers and fruits The most common type of plants on Earth

Monocots “mono” – “one” Have one cotyledon inside their seeds Ex. Corn, rice, wheat, and barley Have flower parts in multiples of three Leaves more narrow than long Vascular bundles are parallel veins in leaves

Dicots Di means “two” Has two cotyledons inside their seeds Flower parts in multiples of four or five Ex. Peanuts, green beans, apples, and oranges. Vascular bundles are the network of veins in leaves http://glencoe.mcgraw-hill.com/sites/dl/free/0078617022/164213/00044690.html

Quiz Label the following plants as dicot or monocot 3. 1. 4. 2.

Quiz Label each plant as vascular or nonvascular. 1. 3. 2. 4.