Gymnosperms flashcard set
Shareef Akbari
Flashcards by Shareef Akbari, updated more than 1 year ago
Shareef Akbari
Created by Shareef Akbari almost 7 years ago

Resource summary

Question Answer
What are the two major innovations that happened in seed plants? What factor did these innovations arise to combat? Seeds Pollen Lack of water
What does a seed contain? Embryo Stored food Seed coat
What does pollen contain? Microspore, in which a microgametophyte develops
Where do the male and female gametophytes, respectively, develop in seed plants? Pollen/Seed
Are gymnosperms heterosporous or homosporous? Heterosporous
What is endosporic development? Gametophyte developing inside the spore
Which generation is dominant in gymnosperms? Sporophyte
Label this diagram.
What are the advantages of having a seed? Protection of the embryo Food storage is available
List the steps of the evolution of an ovule. 1. Retention of megaspores within the megasporangium 2. Reduction to a single megaspore mother cell 3. Survival of a single megaspore following meiosis 4. Endosporic development of megagametophyte within the megasporangium 5. Formation of integument that completely envelopes the megasporangium except for a micropyle 6. Modification of the apex of the megasporangium to receive microspores or pollen grains
What is a micropyle? Small opening in the ovule to accept microspores/pollen
What is pollen? Male gametophyte reduced to 2-4 cells that develops into the microspore wall (endospore)
What is polinisation Transport of pollen to the ovule
What is anemophily? Pollinisation by wind
What is zoophily? Pollinisation by birds and mammals
What is entomophily? Polinisation by insects
What happens after pollination in Cycadophyta and Ginkophyta? Pollen tube grows in the nucellus like a parasite. When it is mature, it releases multi-flagellated sperm that swim to egg (needs water)
What happens after pollination in Coniferophyta and Anthophyta? Pollen tube grows slowly to the archegonium and delivers sperm nuclei directly to the egg. No water is needed, sperm has no flagella and no antheridia are produced by the male gametophyte
What are the phyla that comprise gymnosperms? Cycadophyta Ginkophyta Gnetophyta Coniferophyta
When did Coniferophyta appear? In the carboniferous period
What did Coniferophyta adapt to? Cold and dry climate
What do the needles come out of in Coniferophyta? Fasicles
What is a fasicle? Short shoot that has suspended apical meristem activity
Why are needles good for dry conditions? Low surface area means less water loss. Also don't have many stomata.
What anatomical part of Coniferophyta are strobili? Cones
Are microsporangiate cones on Coniferophyta on superior or inferior branches? Inferior
Are megasporangiate cones on Coniferophyta on superior or inferior branches? Superior
What cells are microspores formed out of in Coniferophyta? 2 Prothallalial cells 1 Generative cell 1 tube cell
Label this diagram
What are the components of an ovuliferous scale? 2 ovules and a subtending sterile bract
What are the steps that happen before fertilisation in male cones in Coniferophyta? 1. Microspore mother cells undergo meiosis to turn into pollen grain composed of a tetrad of microspores. 2. Pollen is liberated from microsporangia and carried by the wind 3. Pollen falls on pollination drop which is produced at the micropyle in the archegonia
What are the steps that happen before fertilisation in female cones in Coniferophyta? 1. Megaspore mother cell undergoes meiosis to produce 4 megaspores 2. Megaspore turns into megagametophyte which is not released 3. Functional megaspore undergoes mitosis 4. Fertilization occurs
What happens after fertilization in Coniferophyta? 1. Pollen tube grows and reaches archegonia 2. 2 sperm nuclei are released 3. 1 sperm nucleus fertilizes the egg, the other degenerates.
Which part of the seed is from the sporophyte generation? And the gametophyte generation? Sporophyte generation: Nucellus remnants and seed coat. Embryo Gametophyte generation: Megagametophyte (storage tissue)
What do Cycadophyta look like? Palm trees
How are Cycadophyta pollinated? Entomophily
Can Cycadophyta symbiose with anything? If so, what? Yes Cyanobacteria
What does dioecious mean? Plants are not hermaphroditic
Where are the cones located in cycadophyta? At the end of stems
Are Cycadophyta sperm flagellated or not? They are.
Do Cycadophyta have wood? Yes
What is the only species in Ginkophyta? Maidenhair Tree
What are the characteristics of Ginkophyta? Large Temperate Deciduous Dioecious Fan-like leaves
What is unique about ginkophyta? Kiterpene Ginkolide that has medicinal uses
Where does pollination happen in Ginkophyta? On the tree.
Where does fertilization happen in Ginkophyta? On the ground
What genera compose Gnetophyta? Ephedra Welwitschia Gnetum
What characteristics do Gnetophyta and angiophyta share? Some cones look like flowers Tracheids AND vessel elements No archegonia in Welwitschia and Gnetum
What is pseudo-double fertilization? When 2 sperm fertilize 2 eggs and make 2 embryos.
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