chapter 9 Flashcards
How many divisions and groupings are in the plant kingdom?
-12 divisions
-4 groupings
embryophytes
retain embryo in female gametangium
what are the cell walls in plants made of?
cellulose
what are chlorophyl a, b and carotenoids part of?
light harvesting reactions
describe alternation of generations
alternation of haploid (gametophyte)and diploid (sporophyte) generations in all land plants
produces gametes
gametophytes
produces spores
sporophyte
gametes undergo fertilization to produce a ________
zygote which becomes a sporophyte
what do sporophytes need to undergo to produce haploid spores?
meiosis
what stage is more dominant for plants to undergo?
sporophyte stage
what plants make up the bryophytes?
mosses, liverworts, and hornworts
what type of habitats are bryophytes found in?
wet environments, moist forests (as epiphytes), and in tundra
when did bryophytes evolve?
around 450 mya
major characteristics of bryophytes:
- nonvascular
- haploid dominance
- seedless
- spores of one type
bryophytes: liverworts
what does wort mean
wort= herb
-name derived from “doctrine of signatures”
what land plant is most closely related to green algae
liverworts (bryophytes category)
bryophytes: liverworts
how do liverworts reproduce
-reproduce asexually by gemmae cups
-reproduce sexually via sperm (located in the antheridia) fertilizing an egg (held in the archegonium)
bryophytes: hornworts
have a _______ which sits on gametophyte and is semi-independent
sporophyte
bryophytes: mosses
how do mosses reproduce
-reproduce asexually: fragmentation of gametophyte
-reproduce sexually: sperm fertilizing egg in gametophyte, sporophyte develops from the archegonium. similar to liverworts
historical background of mosses (bryophytes):
mosses such as sphagnum were used for insulation, absorbent material, and as wound dressing. it also had uses for fuel and soil additive
major characteristics of seedless vascular plants:
- vascular
- diploid dominance
- seedless
- spores of one type
what plants are among the seedless vascular plants
- ferns and fern allies
- club mosses, whisk ferns, horsetails, true ferns
when did seedless vascular plants emerge?
what era were they most dominant in?
shortly after bryophytes, around 430 mya. they were the dominant plants of the late paleozoic era
what did seedless vascular plants co evolve with?
mycorrhizal fungi
seedless vascular plants:
what type of environment do they need for sperm dispersal and fertilization?
moist/ wet environment
what type of habitats are seedless vascular plants located in?
warm, moist habitats
-have the highest diversity
seedless vascular plants: club mosses
- currently in prostrate forms
- tree like during the paleozoic era
-lycopodium spores were used for flash power and for wound dressing
seedless vascular plants: horsetails
- equisetum, are the only living genus
- have true leaves, but the stem is the dominant photosynthetic organ
- prehistoric equisetophyta grew 60 ft tall
- have silica (crystals) in exterior of stem: called the scouring rush
seedless vascular plants: whisk ferns
- have equal branching in stem
- stem is photosynthetic
seedless vascular plants: ferns
- range from tiny aquatic plants to tree ferns 20m tall
- sori on back of leaf contain many sporangia
- sporophyte grows on gametophyte, the sporophyte grows independently after the gametophyte withers away
major characteristics of gymnosperms:
- have seeds
- spores of two types
- vascular
- diploid dominance
gymnosperms:
- what are the types of plants in this category?
- conifers, cycads, ginkgo, and gnetophytes
gymnosperms:
describe the ovule
- ovules are naked at the time of pollination. pollin travels and contacts the ovule directly.
-ovule: female gametophyte
what era were gymnosperms dominant in?
mesozoic era
gymnosperms: cycads
- palm like leaves
- dominated mesozoic era
- location: southern hemisphere
- cycads can produce BMAA toxin that is consumed by bats. Guam residents eat bats, causing health concerns
gymnosperms: ginkgo
- ginkgo biloba is the only living member
- have distinct fan shaped leaves that have been unchanged for 150 million years
- dioecious: separate make and female and female cones.
- used as herbal medicine for improved memory. seeds are given at chinese weddings.
gymnosperms: gnetophytes
-small but diverse group including ephedra, gnetum, and welwitschia
- have male and female ovulate cones
gymnosperms: conifers
- dominant trees of northern forests
- source of lumber, paper pulp, rosin and turpentine
- most massive tree: giant sequoia
- oldest tree: bristlecone pine ( more than 4000 years old)
- intolerant of shade
gymnosperms conifers:
picea vs abies
- picea cones point down
- abies cones point up
major characteristics of angiosperms:
- flowers and fruit plants
- vascular
- diploid dominant
-seeds - spores of two types
- make up the majority of land plants
why did natural selection favor the dominance of the diploid sporophyte over the gametophyte?
- easier to obtain diversity with two copies of genes.
