what are key adaptions for life on land

seeds and pollen grains

5 derived traits of seed plants

• Reduced gametophytes
• Heterospory
• Megaspores ♀ and microspores ♂
• Ovules
• Pollen

Advantages of Reduced Gametophytes

• The gametophytes of seed plants are microscopic
• They develop within the walls of spores that are retained within tissues of the parent sporophyte
• This arrangement protects the developing gametophyte from environmental stress and enables it to obtain nutrients from the sporophyte

What does an ovule consist of

• consists of a megasporangium, megaspore, and one or more protective integuments

sporophyte dominant plants

mosses & non vascular plants.

gametophyte dominant

seed plants

Reduced, independent

(photosynthetic and

free-living)

ferns /7 seedless vascular plants

.what is an integument

how many do angio and gymnosperms have

integument is a layer of sporophyte tissue that envelopes and protects the megasporangium

gymno-1

angio-2

what is a seed

is a sporophyte (2n) embryo, along with its food supply, packaged in a protective coat

• Seeds provide some evolutionary advantages over spores....

• They may remain dormant for days to years, until conditions are favorable for germination
• They have a supply of stored food
• They may be transported long distances by wind or animals

• Most gymnosperms are

cone-bearing plants called conifers

• Three key features of the gymnosperm life cycle are

• miniaturization of their gametophytes
• production of seeds, a dispersible stage in the life cycle
• the transfer of sperm to ovules by pollen

• From the time cones first appear, it takes how many years to produce mature seeds ?

3 years

• The gymnosperms consist of four phyla:

• Cycadophyta (cycads)
• Ginkgophyta (one living species: Ginkgo biloba)
• Gnetophyta (three genera: Gnetum, Ephedra, Welwitschia)
• Coniferophyta (conifers, such as pine, fir, and redwood)

Phylum Cycadophyta

• Individuals have large cones and palmlike leaves
• Unlike most seed plants, cycads have flagellated sperm
• These thrived during the Mesozoic (along with dinosaurs), but most of the few surviving species are endangered

Phylum Ginkgophyta

• This phylum consists of a single living species, Ginkgo biloba
• Like the cycads, this group also has flagellated sperm
• It has a high tolerance to air pollution and is a popular ornamental tree

Phylum Gnetophyta

• This phylum comprises three genera: Gnetum, Ephedra, and Welwitschia
• Species vary in appearance, but are grouped by molecular evidence, and some are tropical, whereas others live in deserts

Phylum Coniferophyta

• This phylum is the largest of the gymnosperm phyla
• Most species have woody cones, but a few have fleshy cones
• Most conifers are evergreens and can carry out photosynthesis all year round

Four adaptations—cuticle, vascular tissue, seeds, and flowers—are key characters defining four major modern plant groups. Which group first evolved vascular tissue?

a)ferns

b)bryophytes

c)flowering plants

d)gymnosperms

a

• Angiosperms have two key adaptations

• Flowers
• Fruits

pericarp

• is the part of the fruit formed when the ovary wall thickens

• One sperm_________ while the other________

fertilizes the egg,combines with two nuclei in the central cell of the female gametophyte and initiates development of food-storing endosperm

what three groups diverged early within angiosperms...

• Amborella trichopoda , water lilies, and star anise

Adaptations critical to plant success in terrestrial environments include seeds, vascular tissue, cuticle, and flowers. Which lists these adaptations in the order in which they appeared?

a)seeds, vascular tissue, flowers, cuticle

b)cuticle, seeds, flowers, vascular tissue

c)cuticle, vascular tissue, seeds, flowers

d)vascular tissue, cuticle, seeds, flowers

c