Plants Common Characteristics

Characteristics Multicellular Multicellular More than one cell More than one cell Cell Wall Cell Wall Made of cellulose Made of cellulose Eukaryote Eukaryote The cells of these organisms have a nucleus The cells of these organisms have a nucleus

Plant History First plants are thought to have begun appearing around 500 million years ago (probably looked like moss) First plants are thought to have begun appearing around 500 million years ago (probably looked like moss)moss First plant fossils are those called psilophytes (some still exist today) First plant fossils are those called psilophytes (some still exist today) Scientists used DNA evidence and the presence of chlorophyll to compare ancient plants with modern plants Scientists used DNA evidence and the presence of chlorophyll to compare ancient plants with modern plants

NOT this Moss

Ancient Examples

Adaptations to Living on Land Roots Roots Absorbs water and minerals from the soil Absorbs water and minerals from the soil Stores food (Ex: carrot) Stores food (Ex: carrot) Anchors a plant to the ground Anchors a plant to the ground Reproduction (Ex: Aspen trees) Reproduction (Ex: Aspen trees)

Roots con’t. Tap Roots – one long, thick main root with many smaller roots branching off main root Tap Roots – one long, thick main root with many smaller roots branching off main root Fibrous Roots – many similarly sized roots that form a dense tangled mass Fibrous Roots – many similarly sized roots that form a dense tangled mass

Quaking Aspen – the largest organism on the planet

Adaptations con’t. Stem Stem Provides structure and support for upright growth Contains vascular tissue to transport materials Woody or Herbaceous Woody or Herbaceous Cambium – A layer of cells in a plant that produces new phloem and xylem cells

Adaptations con’t. Leaves – organ that absorbs sunlight and is responsible for photosynthesis Leaves – organ that absorbs sunlight and is responsible for photosynthesis Cuticle – waxy outer layer that prevents water loss (also on stems and fruits) Cuticle – waxy outer layer that prevents water loss (also on stems and fruits) Stomata – opening in the leaf that allows for carbon dioxide to enter and oxygen to exit Stomata – opening in the leaf that allows for carbon dioxide to enter and oxygen to exit Guard cells – surround the stomata to keep it open during the day and closed at night Guard cells – surround the stomata to keep it open during the day and closed at night

Stomata/Guard Cells

Photosynthesis Revisited The process in which the sun’s energy is converted by a plant, in the chloroplast, to make food The process in which the sun’s energy is converted by a plant, in the chloroplast, to make food Formula: Formula:

Photosynthesis Revisited

Leaves con’t.

Types of Plants Nonvascular – do not have vascular tissue, usually no more than a few cells thick, live close to water Nonvascular – do not have vascular tissue, usually no more than a few cells thick, live close to water Vascular – contain vascular tissue, specially adapted to transport materials, enables taller growth Vascular – contain vascular tissue, specially adapted to transport materials, enables taller growth

Nonvascular Plants Primary methods of transporting materials are: Primary methods of transporting materials are: Osmosis – diffusion of water through a selectively permeable membrane Osmosis – diffusion of water through a selectively permeable membrane Diffusion – movement of particles from an area of high concentration to an area of low concentration Diffusion – movement of particles from an area of high concentration to an area of low concentration

Nonvascular Plants Examples

Vascular Plants Contain Vascular Tissues Contain Vascular Tissues Xylem – transports water and nutrients up the plant Xylem – transports water and nutrients up the plant Phloem – transports food down the plant Phloem – transports food down the plant

Vascular Plants Examples

Other adaptations Phototropism – when plant growth is determined by light (arctic poppy) Phototropism – when plant growth is determined by light (arctic poppy) Thigmotropism – when plant growth is determined by touch (ivy, pole beans) Thigmotropism – when plant growth is determined by touch (ivy, pole beans)

Other adaptations Gravitropism – when plant growth is determined by gravity (most plants) Gravitropism – when plant growth is determined by gravity (most plants) Carnivorous plants Carnivorous plants Uniquely adapted to survive in areas with poor soil (Bladderwort, Venus Fly Trap) Uniquely adapted to survive in areas with poor soil (Bladderwort, Venus Fly Trap)

Uses/Benefits of Plants Aesthetics – look and smell nice, increase the value of a home Aesthetics – look and smell nice, increase the value of a home Lumber – building, firewood Lumber – building, firewood Shade – energy efficient Shade – energy efficient Paper Paper Food – fruits and vegetables Food – fruits and vegetables Health Health Medicines ( Medicines ( Air Quality (Ginkgo biloba) Air Quality (Ginkgo biloba)