Question

1. What is the structure found on moss from which spores are released?
2. The thallus of the liverworts has what structures? What are the function of the structures you listed.
3. Ferns have vasculature. What does this mean and what is the purpose of being a vascularized plant?
4. What structures are found on the prothallus and what is their function?
5. Define:
   1. Microphlls
   2. Megaphylls
   3. Annulus
6. Through what medium do sperm move through to ge to the egg for fertilization? What structure provides movement for those sperm?

Answer 1

1) What is the structure found on moss from which spores are released?

The correct answer is

In moss, spores are produced from structures called sporophytes, the sporophyte stalk called the seta bears the sporangium(spore capsule) on its tip, one sporangium produces upto a million spores. Maturing spore capsules are guarded by a covering called the calyptra that shrivels and fall off when the spores are mature.

A cap called the operculum tops the capsule's opening under the calyptra. The capsule opening (peristome) can have teeth that help hold it closed. Matured spores are released when the capsule top ruptures and drift off to form new plants.

2) The thallus of the liverworts has what structures? What are the function of the structures you listed.

The correct answer is

In liverworts, their green tissue is multiple layers thick and known as a thallus. Depending on the complexity of the thallus, thalloid liverworts can be either simple or complex.

Simple thalloid liverworts have a thallus that is usually several layer thick except at the margins where it only has a single layer of cells. The majority of species have rhizoids on their underside to help with water absorption and anchoring the plant. Several species have a close relationship with fungi.

Complex thalloid liverworts have differentiated and chambered thalli. The upper surface of the thallus is contain air chambers with photosynthetic cells. Relative to other liverworts, the complex thalloid liverworts are well adapted for high light environments and are able to tolerate drought far better

The complex thalloid liverworts have pores similar to stomata but they are unable to open and close. Gases enter into the air chambers via the pores. Lower sections of the thallus is used for the storage of water and nutrients.

The rhizoids of complex thalloid liverworts are also more advanced than other liverworts. They grow in various shapes that help to increase the efficiency of water absorption.

3) Ferns have vasculature. What does this mean and what is the purpose of being a vascularized plant?

The correct answer is

Ferns are said to be vascular plants as They contain two types of vascular tissue that are needed to move substances throughout the plant. The first type of vascular tissue, xylem, is responsible for moving water and nutrients throughout the plant, The other vascular tissue, phloem, is responsible for moving glucose throughout the plant.

The main purpose of vascular system in plants is it carries out two essential functions, namely the delivery of resources (water, essential mineral nutrients, sugars and amino acids) to the various plant organs, and provision of mechanical support. In addition, the vascular system serves as an effective long‐distance communication system, with the phloem and xylem serving to input information relating to abiotic and biotic conditions above and below ground.

4) What structures are found on the prothallus and what is their function?

The correct answer is

The gametophyte in ferns is known as prothallus. It is a small, inconspicuous and multicellular structure which is formed from the germination of haploid spores. It is independent and autotrophic.It is a short-lived and inconspicuous heart-shaped structure typically 2–5 millimeters wide, with a number of rhizoids (root-like hairs) growing underneath, prothallus is generally monoecious as it bears both male and female sex organs i.e. antheridia and archegonia respectively or it may be dioecious if male and female sex organs are present on different plants, so it plays an important role in plant reproduction.

5) Definitions:

Microphylls:

In plant anatomy and evolution a microphyll (or lycophyll) is a type of plant leaf with one single, unbranched leaf vein.Plants with microphyll leaves occur early in the fossil record, and few such plants exist today.

Megaphylls:

Megaphylls, in contrast, have multiple veins within the leaf and leaf gaps above them in the stem and are most frequently found now in all plants.

Annulus:

An annulus is an arc or a ring of specialized cells on the sporangium. These cells are arranged in a single row, and are associated with the release or dispersal of spores.

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