Chapter 19 - Biodiversity of Plants Flashcards
What are some important uses of plants?
Food, clothing (cotton, linen), medicines (aspirin), fuel and heat and building materials (wood), fossil fuels (ancient plants).
Are algae and kelp plants?
No, they’re protists, but algae are the ancestors of plants.
What is biodiversity?
Biological diversity. The variety and variability among living organisms and the ecological complexes in which they occur.
How much are medicines from plants worth worldwide and who depends on these the most?
$40 billion/year and 80% of people in developing countries depend on traditional medicines.
What percentage of all medicines available today are derived from tropical plants?
More than 25%
How many species of vascular plants are there? What percentage of those flower?
About 391,000 of which 94% are flowering plants.
How many new plant species are discovered/described each year?
About 2000
What percentage of plants are threatened by extinction? Why?
Nearly 21% (1 in 5), the largest threats are large-scale habitat destruction.
When do we see the first plant fossils in the geologic record?
475 mya
What adaptations were necessary for plants to move from water onto land (5)?
- Vascular tissue for support (lignin)
- A waxy covering (cuticle) to prevent water loss and stomata (holes) for gas exchange.
- Specialized roots, stems and leaves.
- Pollen and seeds to reproduce.
- Ways to spread seeds (wind, water, animals)
What is vascular tissue? What are the two types?
Specialized tissues for moving water and minerals throughout the plant.
Xylem – dead cells that form pipes for water and minerals.
Phloem – living cells that distribute sugars throughout the plant.
What types of plants have vascular tissue?
Most land plants except mosses which are more primitive.
What differentiates higher plants from mosses and ferns in terms of reproduction?
Pines and flowering plants produce seeds (instead of spores) and use pollen instead of flagellated sperm (so they don’t need water to move male gametes).
What is the general way that plant life cycles work?
Plants have alternating of generations of haploid (1n gametophyte) and diploid plants (2n sporophyte).
What is a gametophyte
generation?
The haploid (1n) generation of a plant that produces sperm and eggs (gametes, as the name suggests).
What is a sporophyte generation?
The diploid (2n) generation of a plant that produces spores (as the name suggests).
What’s a difference between the alternating generations of primitive and more evolved plants?
Primitive plants have a more prominent haploid gametophyte stage. More evolved plants have a dominant diploid sporophyte stage.
What are bryophytes and their characteristics?
Small non-vascular land plants: mosses, liverworts, hornworts. With dominant gametophyte, very small sporophyte, spores not seeds, flagellated sperm that needs water.
What are pteridophytes and their characteristics?
Vascular plants with spores. Ferns, etc. Dominant sporophyte, reduced gametophyte, flagellated sperm that needs water, roots.
What are spermatophytes?
Seed producing plants including the gymnosperms (evergreens) and angiosperms (flowering plants).
What are gymnosperms and angiosperms? What are their characteristics?
Mostly evergreen trees and all flowering plants/deciduous trees respectively. Dominant sporophyte, only gametes are haploid, vascular tissues, pollen, seeds (in cones or flowers/fruit respectively), roots.
Which type of plant is most successful? What percentage of living plants are this type?
Angiosperms- flowering plants.
An estimated 369,000 out of 391,000 species or 94%.
What type of plants are the earliest land plants? When did they appear?
Bryophytes, 475mya.
When did the first vascular plants appear?
425 mya pteridophytes appear.
