Plant Diversity Flashcards
Important plant characteristics used for broad classification
Presence/absence of:
- Vascular tissue
- True leaves and roots
- Seeds
- Fruit
- Dependence on water for fertilisation
Major groups of land plants (Divisions)
- Bryophytes
- Pteridophytes
- Gymnosperms
- Angiosperms
Bryophyte structure
Gametophyte:
- No true leaves and roots
- Very small since no vascular tissue
- Produce gametes
Sporophyte:
- Grows on gametophyte
- Has a capsule containing spores
Thallus
- The name given to the gametophyte plant
- No true roots, stems or leaves
Alternation of generations in plants
- Haploid Gametophytes (n)
- Produce male and female gametes (n)
- Fuse to form zygote (2n)
- Grows into diploid sporophyte (2n)
- Produces spores (n) by meiosis
- Grows into gametophyte (n)
Reproduction in Bryophytes
- Gametophytes produce male and female gametes
- Male gametes swim through water to female gametes
- after fertilisation, zygote grows into sporophyte
- sporophyte makes spores which grow into gametophytes
Bryophyte examples
- Mosses
- Liverworts
- Hornworts
The leafy part of a bryophyte
Thallus
Pteridophyte examples
- Ferns
- Horsetails
- Club mosses
Fern structure
Sporophyte:
- True leaves called fronds
- Fronds often compound leaves
- Vascular tissue
- Often stems form horizontal underground rhizomes
Gametophyte:
- Tiny heart shaped thallus
- Rhizoids
Reproduction in pteridophytes
- Dominant sporophyte (2n)
- Spores (n) produced in sporangia clusters called sori under fronds
- Spores grow into tiny gametophyte (n) which produce gametes
- Male gametes swim through water to female gametes
- after fertilisation, zygote (2n) grows into sporophyte
Gymnosperm examples
- Conifers
- Cycads
- Ginkgo
- Welwitschia
Another name for the gymnosperms
- Naked seeded plants
- Because seed not enclosed by an ovary
Gymnosperm structure
Sporophyte:
- Dominant, often forming huge trees
- true roots and leaves
- vascular system
- specialised reproductive structures called cones
- seeds in cones
Gametophyte:
- Very reduced as pollen or ovules in cones
- Produce the gametes
Reproduction in gymnosperms
- Dominant sporophyte (2n)
- produces cones containing pollen (n) and ovules (n)
- pollen carried by wind to female cone
- pollen grows a pollen tube so that male gamete (n) can fertilise the female gamete (n)
- fertilised ovule grows into a seed containing sporophyte embryo (2n)
- seed dispersed (e.g. by wind)
Examples of angiosperms
- Dicotyledons
- Monocotyledons
Angiosperm structure
Sporophyte:
- Dominant with true leaves and roots
- Vascular tissue
- Wide range of forms from minuscule herbs to giant trees
- Specialised reproductive structures called flowers
- seeds enclosed by an ovary which grows into fruit
Gametophyte:
- very reduced as pollen and ovules
- produce gametes
Reproduction in angiosperms
- Dominant sporophyte (2n)
- produces flowers containing pollen (n) and ovules (n)
- pollen carried by wind to stigma
- pollen grows a pollen tube so that male gamete (n) can fertilise the female gamete (n)
- fertilised ovule grows into a seed containing sporophyte embryo (2n)
- seed enclosed in ovary forming a fruit
- seed dispersed, dispersal often aided by fruit
Plants with a dominant gametophyte generation
Bryophytes
(Mosses, liverworts and hornworts)
The name for the fern gametophyte
Prothallus
Where meiosis occurs in plants?
What cells are produced?
In the sporangium (plural: sporangia)
Spores
The collective name given to seed bearing land plants, Gymnosperms and Angiosperms
Spermatophytes
