MODULE ONE Flashcards
Which organism is the first ancestor to plants?
Green Algae
Which classes make up Bryophytes?
Liverworts
Mosses (1&2)
Hornworts
Which is the oldest evolutionary group that make up Bryophytes?
Liverworts
Which class is most closely related to Green Algae?
Liverworts
List the classes that make up Bryophytes from least to most diverse.
- Hornworts
- Liverworts
- Mosses
Describe the physical characteristics of Liverworts.
Plant bodies are often flattened
Describe the physical characteristics of Mosses.
Mosses are the most diverse class under bryophytes and come in different shapes, colours, and sizes
Describe the physical characteristics of Hornworts.
Plant bodies are often flattened, also grow ‘horns’ to reproduce
How to Bryophytes differ from Vascular Plants?
- Small in size
- Lack vascular tissue
- Lack true roots, only rhizoids (tiny filamentous ‘roots’)
- No or very limited cuticle
What does vascular tissue consist of?
Xylem & Phloem
What is the function of the Xylem?
Transports water through the tissue upwards
What is the function of the Phloem?
Photosynthetic tissues move down to where the plant is growing
Describe the characteristics of the Xylem and the consequences of such.
Xylem cells are very strong and acts as a backbone for the plants resulting in non-woody(herbaceous) plants to grow relatively tall
Describe water transport in Bryophytes.
Water permeates from cell-to-cell passively. Results in less fast transportation and restricts the maximum size of the plant.
Why are Bryophytes typically small?
They do not have xylem (vascular tissue), their cells are less strong and lack a back bone. The way they transport water (cell-to-cell) is slow and less efficient which is another factor that contributes to this characteristic. They lack enforced cells or tissue to keep them upright beyond a small maximum size
Do Bryophytes have true roots? Explain:
They lack true roots, but have rhizoids (tiny filamentous ‘roots’)
- it is good enough for anchoring
- not great for uptake of resources
- unlike vascular plants, rhizoids are not made up of vascular tissue
Since Bryophytes either have no or very limited cuticle, what are the consequences of such adaptation?
Quick loss & quick uptake of water along whole surface
Bryophytes prefer wet/moist ecosystems
List the steps in the life cycle (generalized alternation of generations) of Bryophytes in order.
- Gametes (egg &sperm)
- Fertilization
- Zygote
- mitosis
4.Embryo
-mitosis - Sporophyte
- Meiosis
7.Spores
-mitosis - Gametophyte
-mitosis - Gametes (repeat)
What is the male reproductive organ in Bryophytes called?
Antheridia/Antheridium
What is the female reproductive organ in Bryophytes called?
Archegonia/Archegonium
How many eggs does each archegonium hold?
One
How do Bryophytes take up water?
Shoots
Leaves
Rhizoids
Where are spermatozoids produced in Bryophytes?
Antheridium/Antheridia
What is the name of the structure supporting the spore capsule?
Seta
What is the function of the cuticle?
It is a thin layer used in the vast majority of plants to seal leaves against desiccation. Also a hydrophobic layer.
Describe the characteristics and function of the the spermatozoid.
It has two self-propelled flagellae and chemo-detectors which allow it to swim over short distances towards the female gametophyte to fertilize the egg cell.
What are the conditions for fertilization to occur in Bryophytes?
Water dependent, but a thin water film is enough
When do chemotaxis occur in the Bryophyte life cycle?
Spermatozoids can chemically taste their environment to find the female archegonium
What components make up a Sporophyte?
Seta
Spore Capsule
Which parts of the Bryophyte life cycle is diploid?
Sporophyte
-seta
-wall of spore capsule
Which parts of the Bryophyte life cycle is haploid?
Gametes (Egg and Sperm)
Spores
Gametophyte
Antheridia
Archegonium
Protonema
Spermatozoid
Which generation(s) are short lived in Bryophytes?
The diploid part
-Sporophyte
Which generation(s) are dominant in Bryophytes?
The haploid part
-Gameophyte
Which unit of the life cycle in Bryophytes is wind dispersed?
Spores
Which group among bryophytes is most closely related to lycophytes
Hornworts
Which parts of a plant are photosynthetic in moss?
Gametophyte
Protonema
Which unit of the following life cycle is mobile and self-propelled?
Spermatozoid
Where is the egg cell in Bryophytes contained in?
Archegonium/Archegonia
Which group within bryophytes is most closely related to vascular plants?
Hornworts
What is the name of the structure from which female and male gametophytes grow in bryophytes?
Protonema
Which group among the bryophytes is evolutionary the youngest?
Hornworts
What are the differences between water dependent dispersal and wind-dependent dispersal in Bryophytes?
Water dependent dispersal is short distance is used for spermatozoids. Wind dependent dispersal is long-distance and is used for spores.
In germination, how is the sex of the gametophyte decided?
Half the spores in the spore capsule have the genes to produce female gametophytes, and the other half has the genes to produce male gametophytes.
How do Bryophytes in the desert survive?
They have adapted to survive the complete loss of water. When there is no water, the plant goes into a ‘hibernation’ type state where they do not grow, reproduce, or photosynthesize. When it rains, they uptake water quickly and resume growth.
