ch. 30 Flashcards
characteristics common to seed plants
- heterospory
- reduced gametophytes
- ovules
- pollen
reduced gametophytes
- develop within walls of spores that are retained within tissues of parent sporophyte
- arrangement protects developing gametophyte from environmental stress and obtains nutrients from sporophyte
gametophyte size in nonvascular plants
giant
- sporophyte reduced, dependent on gametophyte
gametophyte size in seedless vascular plants
- small
- gp photosynthetic and free living
- sporophyte dominant
gametophyte size in seed plants
- tiny
- usually microscopic
what are the scales on ovulate cones called
megasporophylls
where are ovulate cones in relation to pollen cones
higher on tree, pollen cones lower
what is inside the female ovulate and male pollen cone?
gametophyte
where are male gametophytes in gymnosperms
pollen cone
where are female gametophytes in gymnosperms
ovulate cone
where are male gametophytes in angiosperms
anthers
where are female gametophytes in angiosperms
ovules
homosporous
plants producing one type of spore
- usually bisexual
- ferns and close relatives
heterosporous
produces 2 dif types of spores, which develop into either male or female gametophytes
- seed plants
- separate sex gametophytes
megasporophylls and microsporophylls
modified leaves
megasporophylls…
- megasporangia
- megasporocytes
- meiosis
- megaspores
- female gametophytes
- mitosis
- ovum or egg
microsporophylls…
- microsporgangia
- microsporocytes
- meiosis
- microspores
- male gametophytes
- mitosis
- sperm
ovule
consists of megasporangium, megaspore, and 1+ protective integuments
how many integuments do gymnosperm megasporangia have
one
how many integuments do angiosperm megasporangia have
two
what does a microspore develop into?
divides by mitosis to create pollen grain
- contains male gametophyte
pollination
transfer of pollen to the part of a seed plant containing the ovules
what happens with a germinated pollen grain
produces pollen tube that discharges sperm into the female gametophyte within the ovule
where are seeds found in gymnosperms
exposed on sporophytes that form cones
where are seeds found in angiosperms
fruits (mature ovaries)
what are most gymnosperms?
cone-bearing plants called confiers
male life cycle of pine
- pine tree is sporophyte that produces sporangia in male/female cones
- pollen cones consist of microsporophylls that bear microsporangia
- microsporangia contain microsporophytes that undergo meiosis to produce microspores
- each microspore develops into pollen grain containing male gametophyte
female life cycle of pine
- ovulate cones consist of megasporophylls with megasporangia and modified stem tissue
- megasporangia contain megasporocytes that undergo meiosis to produce megaspores
- megaspores develop into female gametophytes
4 phyla of gymnosperms
- cycadophyta
- gingkophyta
- gnetophyte
- coniferophyta
cycadophyta
- large cones and palm like leaves
- flagellated sperm
gingkophyta
- single living species: Gingko biloba
- flagellated sperm
- high tolerance to air pollution, popular ornamental tree
gnetophyta
- 3 genera: Gentum, Ephedra, Welwitschia
- vary in appearance, tropical to desert
- Ephedra sinica - weight loss supplement, anxiety
coniferophyta
- largest of gymnosperms
- woody cones, sometimes fleshy
- most are evergreens, photosynthesis year-round
characteristics of angiosperms
- single phylum: Anthophyta
- have 2 key adapatations: flowers, fruit
flower
specialized shoot w/ up to 4 types of modified leaves called floral organs
- specialized for sexual reproduction
- pollinated by insects, animals, or wind
floral organs
sepals, petals, stamen, carpels
sepals
enclose flower
petals
brightly colored to attract pollinators, wind pollinated don’t have bright flowers
stamens
male reproductive organ
- anthers
- filament
carpels (pistil)
female reproductive organ
- stigma
- style
- ovary
what is the pistil made up of
megasporophylls
what are produced in the anthers
microspores that develop into pollen containing male gametophytes
why is the stigma sticky
where pollen is received
what does the ovary contain
the female gametophyte within the ovules
pistil
single carpel or 2+ fused carpels
how does a fruit form
when the ovary wall thickens and matures
- protects seeds and aids in dispersal
- fleshy or dry
angiosperm life cycle
- male gametophytes are contained within pollen grains produced by microsporangia or anthers
- female gametophyte (embryo sac) develops within ovule in ovary at base of stigma
- cross-pollination occurs
- pollen grain lands on stigma and germinates, and pollen tube grows down to ovary
- ovule is entire through micropyle
- double fertilization occurs when pollen tube discharges two sperm into female gametophyte within ovule
- one sperm fertilizes egg, other combines w/ 2 nuclei in central cell of female gametophyte and initiates development of endosperm
micropyle
where pollen tube enters ovule in angiosperms
what does embryo consist of in angiosperm
a root and 1-2 seed leaves (cotyledons)
monocot characteristics
- one cotyledon
- parallel veins
- scattered vascular tissue
- fibrous root system, no main root
- pollen grain w/ 1 opening
- floral organs in multiples of 3
eudicot characteristics
- two cotyledons
- netlike veins
- vascular tissue in ring
- taproot (main root)
- pollen w/ 3 openings
- floral organs in multiples of 4 or 5
most of our food comes from
angiosperms
angiosperm crops that are consumed by humans
wheat, rice, maize, potatoes, cassava, sweet potato
