LESSON 9: D9 - Introduction to Plants Flashcards
Why do some have allergies?
- Some peoples immune systems see allergens such as Pollen as threaths and fight it off
- White blood cells attach to pollen, releasing inflammatory chemicals
-This sitmulates nerve cells and causes mucous membrans to leave fluid
Who atre plants thought to orginate from?
Charophytes
-A group of protists green algae
Characetristics of a plant?
-Multi-cellular
-Eukaryotic
-photosyntheic
-Cell wall of celluose
-Immobile (sessile)
- Reproduce by alteration of generations
How dpes alertnation of genes work for plants?
- They alternate between a diploid sprophyte generation and a haploid gametophyite generation
Sporophyte
Asexual phase
Gametophyte
Sexual phase
Types of Plants: Bryophytes
- Mosses are the most familiar group
- Evolved many features which make other terrestrial plants successful
- no vascular system
- Instead they depend on simple diffusion, osmosis and active transport to survive
-Also have rhizoids- not true roots
This also accounts for their limited capacity for absorption and lack of anchorage
Mosses: Pioneer Plants
are often the first to establish themselves on previously uninhabited area
-As they die and decompose, they enhance the environment
i.e. provide organic matter that enhances the soil and facilitates other plant growth
Just because soemthing is called a moss or a fern does it mean it classifies as so?
No
Peat Moss
Pioneers in Ecosystems
Used in gardening
Used as a fuel in Europe and Asia
Can be chemically altered to form coal
Can be used as antiseptic
Used to mop up oil spills
Absorbent - so was used as surgical dressings in WWI, diapers for babies and in feminine hygiene products
Types of Plants: Tracheophytes
Ferns are tracheophytes- plants that have a vascular system
Earliest vascular plants to evolve
Ferns are the most well known example
How do ferns help our ecosystems?
Play an important role in ecological succession (i.e process of change in the species that make up an ecological community over time)
-Pioneer plants
Fiddlehead Ferns
-young curled fronds of young ferns that are harvested as a vegetable
-Good for you
Types of Plants: Spermatophytes
Seed plants are called spermatophytes
-They have roots, stems, and leaves
-Most recently evolved
-Reproduction NOT dependant on water
-They have a seed which contains a plant embryo
What are subdivisons of tracheophytes
Vascular plants
Types of Spermatophytes: Gymnosperms
pines, junipers, spruces, cedars and other cone-bearing plants
-thin- needle like leaves
Help plant survive harsh dry, hot and cold weather
-Needles covered in a hard waxy cuticle
-Deep penetrating roots
Yew
Paclitaxel (a well known natural source cancer drug) can be isolated from the tree bark
Types of Spermatophytes: Angiosperms
- flowering plants
-All are tracheophytes
-Because they have vascular tissue
-All will have flowers and fruit for reproduction