Presentation on theme: "PLANT BIOLOGY: INTRO Unit 5 – Plant Anatomy, Growth & Function."— Presentation transcript:
PLANT BIOLOGY: INTRO Unit 5 – Plant Anatomy, Growth & Function
PLANTS IN OUR SOCIETY In small groups, brainstorm uses for plants in OUR society.
USES FOR PLANTS IN OUR SOCIETY Fuel (ethanol from corn) Medicine (aloe vera, med. marijuana) Tools (wood, toxins in wood to kill fish, weapons) Food Construction Alcohol (potato vodka; grapes wine) To breathe! Shade Fragrances Composting Narcotics Clothing (ex. Hemp, cotton) Dyes, tattoos, henna Paper Soaps Flour, mint, herbs, tea, spices Make-up, cosmetics, beauty and skin care, jewellery
Important Crops in Canada (thousands of tonnes) Wheat 28, 611 Canola 12, 642 Barley 11, 781 Grain corn 10, 592
Monoculture One type of plant is grown in place of the natural ecosystem What are some pros and cons of this approach?
Learning Check Pg 539, Q 1-6
Medicinal Uses 25% of prescription medicines contain plant extracts Rosy periwinkle (vincristine andvinblastine) – childhood leukemia and Hodgkins. Survival rates have gone from 20% to 90% with these 2 compounds Goldenseal – colds and sore gums Ginseng – immune system function
Biofuels Most biofuels come from corn (ethanol). What are some pros and cons of this method? Research is being done to get fuel from cellulose and oil from algae Read Quirks and Quarks on page 542
Erosion Control The paradox of farming: farmers need good soil to farm, yet farming destroys good soil. 2.5 million acres each year are lost to urbanization and soil erosion. About 1/3 of the country's topsoil has been lost due to urbanization and soil erosion.
Medicinal Plants Assignment Pg 573
KINGDOM PLANTAE Plants evolved about 500 million years ago from simple green algae that lived in the ocean. All plants are autotrophic and some, like the famous Venus fly-trap, can also be heterotrophic. All plants are eukaryotic and multicellular.
PLANT CELLS Like animal cells, plant cells contain a nucleus and organelles, but they have two distinguishing features: –Cell wall (made of cellulose, a complex carbohydrate, provides rigid structural support; difficult to digest) –Chloroplast (organelle that conducts photosynthesis) Animal cells have lysosomes that release the cellular equivalent of digestive enzymes. Why dont plants need these?
PLEASE... CONSIDER THE FOLLOWING: How can plants stand up straight without a skeleton?
PLANT DIVERSITY Currently over species of plants, including: –Mosses –Ferns –Conifers –Flowering plants Most plants live on land and can withstand a wide variety of climates. Cacti live in arid, dry areas whereas mosses need to be in moist environments to survive.
CLASSIFYING PLANTS Plants are classified based on the presence or absence of vascular tissue Vascular tissue can be compared to arteries and veins: a network of specialized cells that allows plants to transport water, minerals and sugar throughout the plant What would you expect a non- vascular plant, without vessels to transport nutrients and water, to look like?
Plants Non-vascular (ex. moss) Cannot transport foot or water between plant parts Transport of fluid is through simple absorption or osmosis Must live in moist environments; need water for reproduction Vascular (ex. tree, sunflower) Contain a vascular system allowing for transportation of nutrients / water throughout the plant
WHAT MIGHT VASCULAR PLANTS LOOK LIKE?
FUNCTION OF STEMS 1.Support system for plant body 2.Transport system carries water & nutrients (through vascular tissue!) 3.Holds leaves & branches upright Looking at the picture below: What years had the most rain? What years experienced the worst drought?
FUNCTION OF LEAVES 1.Main photosynthetic organ 2.Broad, flat surface increases surface area for light absorption 3.Have systems to prevent water loss Stomata open in day but close at night or when hot to conserve water Waxy cuticle on surface 4.System of gas exchange Allow CO 2 in and O 2 out of leaf Elephant Ear Plant
LEAF STRUCTURES 1.Cuticle: waxy layer; covers upper surface –Protects leaf against water loss 2.Veins: transports water, nutrients and food –Made of xylem and phloem vascular tissue 3.Mesophyll: contains cells that perform photosynthesis b/c they contain chloroplasts. 2 Guard Cells Surround each Stoma M e s o p h y l l (Opening) Leaf Cross-Section Stoma Veins Cuticle
LEAF STRUCTURES 4.Guard cells: Cells that open and close the stoma Conserve water by preventing excess water transpiration 5.Stomata: openings in leafs surface; when open: GAS EXCHANGE: Allows CO 2 in & O 2 out of leaf TRANSPIRATION: Allows excess H 2 O out of leaf Guard Cells Stoma
FUNCTION OF ROOTS 1.Anchor & support plant in the ground 2.Absorb water & minerals 3.Hold soil in place Fibrous Roots Root Hairs
STRUCTURE OF ROOTS 1.Root Hairs: increase surface area for water & mineral absorption 2.Meristem: region where new cells are produced 3.Root Cap: protects tip of growing root Root Hairs Meristem Root Cap
QUIZ TIME! BEFORE WE CONTINUE… VASCULAR OR NON-VASCULAR?
VASCULAR PLANTS Gymnosperms Naked seeds are not enclosed in an ovule (like a pine cone). Plants are usually evergreens. Ex. pines, cedars, spruces and firs. Angiosperms Mature seed is surrounded by the ovule (think of an apple). Angiosperms are trees/plants that shed leaves every autumn. Ex. Oaks, maples and dogwoods are examples of deciduous trees. Contain a vascular system allowing for transportation of nutrients / water throughout the plant
QUIZ TIME! BEFORE WE CONTINUE… GYMNOSPERM OR ANGIOSPERM ?