biol topics 14-18 Flashcards
Bryophytes
Non vascular plants that live on land, includes hornworts mosses and liverworts
Form paraphyletic group with three phyla of non vascular plants
Characteristics of Bryophytes
-absence of true vascular tissue and lignin, small in size because of lack of structural support and lack of complex nutrient system
-absence of roots- water is absorbed trough the surface through rhizoids live in habitats rich in water
absence of true leaves
Characteristics of life cycle in bryophytes
the sporophyte (2n) are unbranched
the gametophyte 1n stage is more larger and longer living .
Free living haploid stage is the most dominant stage of life, survival of sporophyte depends on gametophyte
sporophyte is physically attached to gametophyte and uses for nutrients
Typical life cycle Gametophyte stage non vascular
Gametophyte multicellular 1n stage:
Haploid 1n spores are released
spores germinate into gametophytes-composed of protonema and gametophore
gametophytes mature as separate male and female plants and each produce gametes through mitosis
sperm travels to the archeridium from the antheridium through water
Typical life cycle sporophyte stage non vascular
Diploid zygote is formed through fertilization and is nourished by the female gametophyte the zygote develops into a diploid embryo and then a diploid sporophyte all retained in the archegonium. The sporophyte matures into a sporangium and spores are produced through meiosis and then dispersed through the air.
liverworts
absence of xylem and phloem
absence of stoma
organelle called oil bodies
stabilize soil
mosses
absence of xylem and phloem
presence of stoma
facilitate water retention
Hornworts
absence of xylem and phloem
presence of stoma
and have one large chloroplast
symbiotic relationship with cyanobacteria
Characteristics of vascular plants
-vascular tissue in sporophyte. but not gametophyte
-vascular tissue provides support
-xylem and phloem to transport nutrients
-Sporophyte occupies the dominant part of the life cycle and do not rely on gametophyte for nutrients dominant part of life cycle
-true roots and leaves
Microphylls and macrophylls
Microphylls- small leaves with only a single vein
macrophylls- large leaves with multiple vascular systems
sporophylls are leaves that contain sporangia
sori- sporangia undersides of sporophylls
stroboli-cone like formed by grouping of sporophylls
Homosporous and heterosporous
Homosporous-single type of spore that develops into bisexual gametophytes most seedless vascular plants
Heterosporous-two types of spores
megaspores-develop into female gametes and microspores develop into male gametes ALL SEED PLANTS
Life cycle of vascular plants
haploid spores released and germinate into gametophytes which mature into male and female diploid zygote formed develops into sporophyte which matures in the archegonium and gametophyte dies off and sporophyte remains independent
Phylum lycophyta
microphyll leaves
stroboli containing sporangia
reproduction via spores
Phylum monilophyta
megaphylls
sporangia have spring like structures that catapult spores
most ferns are homosporous
Seed
adaption of terrestrial plants embryo packaged with a store of food and a protective coat
Traits of seed plants
-reduced gametophytes develop in spore wall and retained in sporophyte tissues becomes more dependent on sporophyte
-All seed plants are heterosporous
-Ovules
-pollen
-seeds
Ovules
-contains megasporngium 2n, megaspore 1n, and one or more protective integuments 2n
gymnosperm has 1 integument and angiosperm has 2 integuments
develop into seeds after fertilization
Pollen
microspores develop into male gametophyte within pollen grains
cell walls are coated with a layer of sporopollenin
Seeds
develop from a fertilized ovule
Gymnosperms
vascular plants with naked seeds
seeds are exposed on sporophylls that form stroboli
pollen and ovulate cones
Phylums of gymnospersm
Cycadophyta- cycads are dioecious, flagellated sperm
Ginkophyta- fan shaped leaves
Gnetophyta- xylem contains vessel elements
Coniferophyta- largest division and xylem lacks vessel elements rely on wind to pollinate
Angiosperm shared traits
Shared with land plants
-alternation of multicellular generations
Shared with seed plants
-sporophyte is the most dominant stage gametophyte are micro and depend on the sporophyte
Features of angiosperm
3 Fs
Flowers, double fertilization and fruits synapomorphies
Parts of the flower
sepals- sterile and modified leaf that protect the flower bud
petals- sterile attract pollinators
stamen- pollen producing stalk and anther
carpals- ovule producing ovary style and sigma one or more fused into a pistil
