Gymnosperms, Angiosperms, Fungi Flashcards
What is the definition of an embryo in seed plants?
An immature diploid sporophyte that comes from a zygote.
When did seed plants (gymnosperms) originate?
360 million years ago.
What are the key features of seed plants?
- Reduced gametophytes
- Heterospory
- Ovules
- Pollen
- Seeds
What does LUCA stand for in the context of gymnosperms?
Last Universal Common Ancestor, which existed 350-310 million years ago.
What is the seed coat derived from?
The maternal plant’s integument.
Define heterospory.
Production of large spores in megasporangia (female gametophyte) and small spores in microsporangia (male gametophyte).
What are the main hypotheses regarding ovule and seed evolution?
- Heterospory
- Endospory
- Reduction to 1 functional megaspore
- Retention of megaspore
- Evolution of integument with a micropyle
What is produced from the male cone in pollen development?
Microspores that develop into pollen.
What happens during fertilization in gymnosperms?
- Pollen lands on ovule
- Megaspore released
- Germinates with pollen to form an embryo
What constitutes a gymnosperm seed?
- Seed coat
- Food supply
- Embryo (new sporophyte)
What is the significance of lignin in wood production?
It makes the tissue more robust, allowing plants to grow and increase complexity.
Name a fossil lineage of woody ferns.
- Archaeopteris
- Medullosa
What are the two families of Cycadophyte?
- Cycadaceae
- Zamiaceae
What is unique about Ginkgophyta?
It has an extensive fossil record and only one living species, Ginkgo biloba.
How many living genera are in Gnetophyta?
Three: Ephedra, Welwitschia, and Gnetum.
What are the characteristics of Conifers?
- Heterogeneous group
- Dominated land 240 million years ago
- Various seed dispersal mechanisms
What is the composition of Pinaceae?
12 genera, 225 species including Pinus, Abies, Cedrus, Picea.
What characterizes Cupressophytes?
- 6 families
- Monoecious and dioecious species
- Evergreen leaves
What caused the decline of gymnosperms?
Changes in environment, evolution of flowering plants.
When did angiosperms become dominant?
Since the early Cretaceous period, about 130 million years ago.
What are the key characteristics of angiosperms?
- Enclosed carpels
- Double fertilization
- Endosperm tissue (3n)
- Xylem and phloem
Describe double fertilization in angiosperms.
Two sperm nuclei travel in the pollen tube; one fertilizes the egg to form an embryo, the second forms the endosperm.
What are basal groups in angiosperms?
- Amborellales
- Nymphaeales
- Austrobaileyales
What distinguishes monocots from eudicots?
Monocots have one cotyledon, while eudicots have two cotyledons.
