Lab Practical 2 Flashcards
Bryophytes differ from most land plants because they lack
Vascuclar tissue
Term for the life cycle of plant species where both the diploid and the haploid phases of the life cycle are multicellular
Alternation of Generations
As a result of no vascular tissue, plant form and structure in mosses are limited in several ways:
- Cannot grow very large bc no strong supporting tissue to keep body erect
- Must live in damp places bc root like rhizoids do not penetrate deep into the soil
- The photosynthetic and non-photosynthetic parts must be close together bc there is no vascular tissue to transport nutrients
Life cycle of a moss:
[Fertilization-Zygote-Mitosis-Embryo-Mitosis-Gametophyte, sporophyte, capsule, spores] Diploid [Meiosis-Spores-Mitosis-Female/male gametophyte-Mitosis-Archegonium (egg)/Antheridium (sperm)]
Which is the dominant generation in mosses?
Gametophyte
Is the moss sporophyte haploid or diploid?
The moss sporophyte is haploid and the gametophyte is diploid.
What is the function of the foot at the base of the seta?
The foot is how the sporophyte is connected to the gametophyte or bottom of the stalk.
What type of cell division gives rise to spores?
Meiosis, spores are haploid
Why are the spores released as high above ground as possible?
So that they can be carried by the wind.
When a spore germinates, what does it initially become?
Gametophyte
Lycophytes
Club and spike mosses, dominant sporophyte possessing true vascular tissue and leaves with a single vein
Life cycle of a fern:
[Fertilization (zygote)-Mitosis (embryo)-Mitosis-Gametophyte with young sporophyte-Mitosis-Sporophyte (Leaves, fiddlehead rhizome, roots)-Sorus (Sporangium in indusium)-Sporangium] Diploid [Meiosis-Spores-Mitosis-Prothallus with rhizoids-Mitosis-Archegonium (egg)/Antheridium (sperm)] Haploid
Prothallus
Heart-shaped photosynthetic gametophyte structure of ferns
Bears archegonia and/or antheridia
Anchored to substrate by root-like rhizoids
Archegonia, antheridia, and rhizoids are all located on the lower surface of the prothallus
Gymnosperms
Naked seed
In conifers ____________ hence water is no longer a requirement for fertilization
Sperm are non-flagellated
Fascicle
A short shoot
Leaves of conifers are needle-shaped and grouped within a sheath
Number of leaves borne together
2 or 5
Determines shape of leaf in cross section
Number is distinctive for each species
Conifer leaf structure
Thick walled epidermis, then indentations which are stomata, then many oddly shaped thin-walled cells containing chloroplasts-mesophyll, then vascular tissue in center
Xerophytic feature
Morphological and physiological adaptations that enable an organism to survive under water deficit
What advantages are there for conifer leaves to be needle-like with sunken stomata?
Reduces water loss
How is vascular tissue arranged?
In a bundle in the center of the leaf
How many bundles are there?
Two bundles
How does a conifer leaf differ from a typical angiosperm leaf?
Angiosperm leaves are bigger
What is the function of resin?
Is used to seal over wounds to tissue, prevents pathways for insects and fungal infections
Pine life cycle:
Embryo (megagametophyte, embryo, seed coat)-Seedling (sporophyte)-Female cone (Ovuliferous scaled), Male come Microsporangium (Microspore and microsporophyll)-One ovuliferous scale (Bract, integument, megapore mother cell, ovuliferous scale, megasporangium)-Immature megagametophyte-Megagametophyte and archegonium with egg cell
Which generation is dominant in the conifers? Highly reduced and photosynthetically dependent?
Sporophyte, gametophyte
Microsporophyll
Leaves bearing little spores
Bears two microsporangia which produces microspores
The male cone consists of _____________ with numerous attached _________________
Central axis, microsporophylls
Microgametophyte having divided twice into four nuclei is called a
Pollen grain
What type of cell division produces microspores?
Meiosis
Function of wings of the pollen grain
Aid in pollen dispersion via wind
Megasporangium
Where the egg is held in a female cone
Megagametophyte
Nucleus of a megaspore that divides to form up to 256 nuclei which are eventually enclosed by cell walls
