Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
30 Cards in this Set
- Front
- Back
|
Lichens are composite organs made up of...
|
a mycobiont (fungus) and a phyco/photobiont (alga)
|
|
|
What does the mycobiont determine?
|
Lichen morphology
|
|
|
Out of the myco and phycobionts which can exist independantly?
|
Phycobionts
|
|
|
What is the body of lichens called?
|
The thallus
|
|
|
What are the 3 main types of lichen thallus?
|
Crustose (small, adheres to substratum)
Foliose (leaf like, loosely adheres to substratum) Fruticose (erect/pendulous, often shrubby) |
|
|
What are the lichens niche uses in the environment?
|
food, shelter, bird nesting material, preventing erosion
|
|
|
What is the latin name for blue green algae?
|
Cyanobacterium (its nitrogen fixing)
|
|
|
What is an indicator species?
|
an organsim that describes the state of the environment at any given time. May also be a biomonitor.
|
|
|
Are lichens biomonitors?
|
Yes... can indicate
-arid regions prone to desertification -overgrazing -forest dieback -wilderness designation (hihg abundance) |
|
|
Why are lichens good biomonitors for air pollution?
|
Because they absorb atmospheric moisture including water soluble pollutants such as SO2.
|
|
|
Human uses for lichens include...
|
-antiobiotic properties of secondary compounds
-sunblocks - high UV absorbtion -som lichen polysaccharides are anti tumor/viral/inflammatory -insecticides |
|
|
Lichens are morphologically/chemically plastic which means...
|
they have different
sizes thickness no. of reproductive structures colour secondary compounds |
|
|
How do lichens reproduce?
|
With complexity... the fungus and the alga both reproduce asexually
|
|
|
Why are very few lichens endemic?
|
Small reproductive bodies are easily transported in the atmosphere leading to worldwide distribution.
|
|
|
What are the three bryophyte groups?
|
Bryophyta - Mosses
Hepatophyta - Liverworts Anthocerophyta - hornworts |
|
|
What do the byrophytes lack that most other plants have?
|
Xylem and phloem
|
|
|
What are the two main stages/parts of bryophytes? Are they annual or perennial?
|
Sporophyte - annual
gametophyte - perennial (domminant) |
|
|
What are hydroids?
|
elongated cells that exist in sporophyte stalks similar to xylem
|
|
|
What are leptoids?
|
Cells similar to phloem that occurs in some mosses
|
|
|
What attaches moss to the substrata?
|
Rhizoids
|
|
|
Why does moss require lots of water for reproduction?
|
So the biflagellated sperm can swim to the egg
|
|
|
What are moss eggs contained in and what is it's components?
|
The archegonia consists of a stalk, egg containing venter, neck and neck canal.
|
|
|
What do moss sperm develop in?
|
The antheridia
|
|
|
What do sperm attach to a moss egg with?
|
A pheremone
|
|
|
What are splash cups?
|
Little cups full of clusters of antheridia. Water droplets splash sperm out.
|
|
|
Where do zygotes in byrophytes often develop?
|
In the venter of the archegonia until it develops into a sporophyte (where it has one foot embedded in the archegonium).
|
|
|
What are the three types of spore discharge for the Hepatophyta (liverworts)?
|
1- Capsule dries, splits open, elaters dry, coil and then explode!
2 - Capsule splits open, elaters dry and twist. 3 - Sporangium dries, splits into 4, elaters dry and one side becomes suddenly detached from the inside of the capsule. |
|
|
What are the 3 main types of reproduction in mosses?
|
Fragmentation
Deciduous tips specialised propagules called gemmae |
|
|
What can abnormal growth in lichens indicate?
|
-forest dieback, they are used to indicate forest health
|
|
|
What attaches a moss to the substratum?
|
Rhizoids
|
