Ch 17 Plants Colonization of Land

PLANT EVOLUTION AND DIVERSITY Plants evolved from green algae Molecular, physical, and chemical evidence Indicates that green algae called charophyceans are the closest living relatives of plants LM 444  Figure 17.1A, B Coleochate Chara

Plants have adaptations for life on land Plants are: multicellular photosynthetic eukaryotes

Plants have some specific adaptations That are not found in algae Plant Roots anchor plant; absorb water and minerals from the soil Reproductive structures, as in flowers, contain spores and gametes Cuticle covering leaves and stems reduces water loss; stomata in leaves allow gas exchange Leaf performs photosynthesis Surrounding water supports alga Stem supports plant and may perform photosynthesis Whole alga performs photosynthesis; absorbs water, CO2, and minerals from the water Holdfast anchors alga Alga Figure 17.2A

Obtaining Resources from Two Locations Apical meristems Are the growth-producing regions of a plant Help maximize exposure to the resources in the soil and air

Maintaining Moisture A waxy cuticle covers the stems and leaves of plants And helps retain water Stomata Are tiny pores in leaves that allow for gas exchange

Plants have vascular tissue Which helps distribute nutrients throughout the organism Figure 17.2B Xylem Phloem

Reproducing on Land Many living plants Produce gametes that are encased in protective structures “Gametangia”

Plant diversity reflects the evolutionary history of the plant kingdom Some highlights of plant evolution Origin of vascular plants (about 420 mya) Origin of seed plants (about 360 mya) Origin of land plants (about 475 mya) Seed plants Land plants Bryophytes (nonvascular plants) Vascular plants Seedless vascular plants Liverworts Hornworts Mosses Lycophytes (club mosses and relatives) Pterophytes (ferns and relatives) Angiosperms Gymnosperms Figure 17.3A

Bryophytes lack vascular tissue and include The mosses, hornworts, and liverworts Figure 17.3B

Ferns are seedless vascular plants With flagellated sperm Figure 17.3C

Seedless plants dominated vast “coal forests” Ferns and other seedless plants Once dominated ancient forests Their remains formed coal Figure 17.7

Strip Mining in SE Kansas

Seed plants Have pollen grains that transport sperm Protect their embryos in seeds

Gymnosperms, such as pines Produce seeds in cones Figure 17.3D

The seeds of angiosperms Develop within protective ovaries Figure 17.3E

The structure of a fruit reflects its function in seed dispersal Fruits are adaptations that disperse seeds Figure 17.11A–C

Kopi Luwak $100/llb Kopi Luwak coffee comes from the Indonesian island of Sumatra, an area well-known for its excellent coffee. Also native to the area is a small civit-like animal called a Paradoxurus. That's the scientific name, the locals call them luwaks. These little mammals live in the trees and one of their favorite foods is the red, ripe coffee cherry. They eat the cherries, bean and all. While the bean is in the little guy's stomach, it undergoes chemical treatments and fermentations. The bean finishes its journey through the digestive system, and exits. The still-intact beans are collected from the forest floor, and are cleaned, then roasted and ground just like any other coffee. The resulting coffee is said to be like no other. It has a rich, heavy flavour with hints of caramel or chocolate. Other terms used to describe it are earthy, musty and exotic. The body is almost syrupy and it's very smooth. One must wonder about the circumstances that brought about the first cup of Kopi Luwak coffee. Who would think to (or even want to) collect and roast beans out of animal feces? Perhaps a native figured it was easier to collect the beans from the ground this way, rather than having to work harder and pick them from the trees? We'll likely never know. But because of the strange method of collecting, there isn't much Kopi Luwak produced in the world. The average total annual production is only around 500 pounds of beans. Because of the rarity of this coffee, the price is quite outrageous. If you can find a vendor, the current cost for a pound of Kopi Luwak is around $300 or more