Bell Ringer

How are plant and animal cells different? How are they alike? Give at least three examples of each.

Chapter 12Classifying PlantsMr. Perez

An Overview of Plants

Plant characteristics Range in size from

microscopic water ferns to tall sequoias (100 meters tall)

Most have roots that hold them in place

Plants are adapted to nearly every environment on Earth Frigid cold areas Hot, dry deserts

All plants need water

An Overview of Plants

Plant cells include: Cell membrane Nucleus Other cell structures

In plant cells, but not animal cells: Cell wall (protection and structure) Chlorophyll & chloroplast (green pigment that

traps sunlight and turns it into food) Central vacuole (store water)

Plant vs. Animal Cell

An Overview of Plants

Origin and Evolution of Plants The first plants that lived on land could only live

in damp areas Ancestors were probably green algae that lived in

the sea Green algae contains chlorophyll that carries out

photosynthesis Today, plants and green algae have the same

types of chlorophyll and carotenoids Carotenoids are red, yellow or orange pigments

also used in photosynthesis

An Overview of Plants

The fossil record of plants is not as complete as that of animals The oldest plant fossils are 420

million years old (Cooksonia)

Scientists believe that some of the early plants evolved from green algae

Cone-bearing plants show up in the fossil record 300-350 mya

Flowering plants show up in the fossil record 120 mya

An Overview of Plants

Advantages of life on land More sunlight

and carbon dioxide (CO2) which is needed for photosynthesis

An Overview of Plants

Protection and support on land Cuticle: waxy, protective layer secreted by cells

onto the surface of the plant. Prevents massive water loss.

Cell wall containing cellulose, a chemical compound that can be used by plants to make sugar. Long chains of cellulose provide support and structure

Structures that allow movement of water, nutrients and food throughout the plant

Reproduction Water resistant spores Water resistant seeds in cones or flowers

An Overview of Plants

An Overview of Plants

http://studyjams.scholastic.com/studyjams/jams/science/plants/plant-adaptations.htm

An Overview of Plants

Vascular

Contain tube-like structures that carry water and

nutrients throughout the

plants

Nonvascular

Do not contain tube-like

structures and move water and

nutrients throughout the

plant other ways

Seedless Plants

Seedless nonvascular plants Do not grow from seeds Contain only a few cells Only 2 – 5 cm tall Instead of roots, they contain rhizoids Grow in damp places No flowers or cones Reproduce using spores

Mosses, liverworts and hornworts are examples

Seedless Plants

Seedless Plants

Nonvascular plants and the environment Important in the ecology of many areas Can withstand long, dry periods Can grow in thin soils Spores are carried by the wind Mosses are usually the first to grow in new or

disturbed areas, this makes them a pioneer species

Seedless Plants

Seedless vascular plants Contain vascular tissue (tubes used to carry

water and nutrients) Can grow bigger than seedless nonvascular

plants

Examples include ferns, pines, spike mosses and horsetails

Seedless Plants

Importance of seedless plants Formation of coal Formation of peat (soil condition and fuel) Houseplants Landscape Gardening Food Folk medicines

Seed Plants

Most seed plants have: Leaves (where photosynthesis

occurs) Stems (support plants and move

materials through vascular tissue from root to the rest of the plant)

Roots (collect water and nutrients, anchor plant to ground and store food)

Vascular tissue (tube-like) Seed

Seed plants are split into two groups Gymnosperms Angiosperms

Seed Plants

Open and close stoma

Seed Plants

Seed Plants

Gymnosperms- vascular plants that produce seeds that are not protected by fruit Means “naked seed” in the Greek language Contain needle-like leaves Many are called evergreens Four divisions:

1. Conifers- pines, firs, spruces, redwoods, junipers

2. Cycads

3. Ginkgoes

4. Gnetophytes

Seed Plants

Seed Plants

Angiosperms- vascular plant that flowers and produces fruits with one or more seeds Flowers vary in size, shape and color

Some develop into fruit, which carry seeds Divided into two groups (see next slide)

Monocots- have one cotyledon Dicots- have two cotyledons

Seed Plants

Seed Plants

Importance of seed plants Provide wood Provide resin Food Fibers for clothing

Classwork

P. 353 # 1-3, 5-6

Resources

Florida Science Grade 8

Glencoe Science & McGraw Hill Publishing

Google Images