Post on 26-Dec-2015
Section 1
List some plants you know in general◦ Trees◦ Flowers◦ Vegetables◦ Fruits◦ Field crops
Wheat Rice Corn
There are between 260,000 and 300,000 plant species that have been identified
Plants range in size◦ Microscopic to giant trees
Have roots or root-like structures◦ Hold them into the ground
Adapt to different environments
Plants are made of cells◦ Cell membrane, nucleus, and other cellular
structures ◦ Have a cell wall that provides structure and support
Animal cells DO NOT have a cell wall
Plants cells contain the green pigment chlorophyll◦ Makes them green◦ Needed for photosynthesis◦ Found in the cellular structure chloroplasts
Most plant cells have a central vacuole◦ Regulates water content inside of a cell◦ Stores pigments that make some flowers red, blue,
or purple.
The first plants probably could only survive in damp areas
Their ancestors were probably green algae that lived in the sea◦ Today plants and green algae have the same types of
chlorophyll and carotenoids in their cells◦ Carotenoids are red, yellow, or orange pigments that
are also used for photosynthesis
Plants and green algae have a common ancestor
Plants usually decay before they become a fossil this makes tracing the plant history difficult
The oldest plant fossils are 420 myo
Some of the early plants evolved into the plants that exist today
Cone-bearing plants (pine trees) probably evolved from a group of plants 350 million years ago
Flowering plants did not exist until 120 million years ago
Advantages to life on land for plants◦ More sunlight and carbon dioxide – need for
photosynthesis
Cuticle: Waxy, protective layer secreted by cells onto the surface of a plant◦ Slows water loss
Cellulose: Provide structure and support for the plant
Vessels: Distribute materials throughout the plant
Cells of some plants secrete other substances into the cellulose to make the cell wall stronger◦ Oaks and pines could not grow without this
substance
For plants on land:◦ Structures distribute water, nutrients, and food to
all plant cells
To reproduce on land some plants developed water-resistant spores
Other plants produce water-resistant seeds in cones or in flowers which develop into fruit
The two main plant groups:◦ Vascular: Have tube-like structures to transport
water, nutrients, and other substances throughout the plant
◦ Nonvascular: Do not have tube-like structures for transport. These plants use other methods to transport water, nutrients, and other substances.
Plants are named using the two part naming system binomial nomenclature