Post on 05-Apr-2018
8/2/2019 Adaption of Seed Plant
1/23
1. Describe the adaptations of seed plantsthat have contributed to their success on
land.1. Reduction of the gametophyte
2. Origin of the seed zygote with food
supply and protective coat3. Evolution of pollen plants no longer tied
to water for fertilization
8/2/2019 Adaption of Seed Plant
2/23
2. List the four divisions of gymnosperms.
1. Cycadophyta cycads
2. Ginkgophyta ginkgoes3. Gnetophyta gnetophytes
4. Coniferophyta conifers
8/2/2019 Adaption of Seed Plant
3/23
3. Describe the structures of ovulate andpollen cones of a pine and distinguish
between the two. Pollen cones have microsporangia; undergo meiosis
to produce haploid microspores which develop intopollen
Ovulate cones have megasporangia; undergomeiosis to produce large megaspores that developinto the female gametophyte
most trees bear both pollen & ovulate cones(heterosporous) which develop on differentbranches
8/2/2019 Adaption of Seed Plant
4/23
4. Describe the life history of a pine and indicatewhich structures are part of the gametophyte
generation and which are part of the sporophytegeneration.
It takes 3 years to complete the pine life cycle1. Pollen grain burrows into ovule2. Cell undergoes meiosis to make 4 haploid megaspores;
one survives and grows into the multicellulargametophyte
3. 2 or 3 archegonia, each with an egg, develop inside4. More than a year after pollination, eggs are ready to
be fertilized pollen tube grows through
5. One zygote develops into pine embryo (sporophyte)6. The pine seed then blows away and germinates
elsewhere
8/2/2019 Adaption of Seed Plant
5/23
8/2/2019 Adaption of Seed Plant
6/23
5. Point out the major life cycle differences
in ferns and pines. Pines are much more complex
Pine reproduction takes about 3 years
Pines dont need water for fertilization
8/2/2019 Adaption of Seed Plant
7/23
6. Distinguish between pollination and
fertilization. Pollination pollen into stigma of carpel
- is a prerequisite to fertilization
Fertilization the union of haploidgametes to form a diploid zygote
8/2/2019 Adaption of Seed Plant
8/23
7. Describe a pine seed and indicate whichstructures are old sporophyte, gametophyte,
and new sporophyte.Pine seed:
1. Embryo 2n new sporophyte2. Food source n gametophyte
3. Surrounding seed coat 2n old
sporophyte
8/2/2019 Adaption of Seed Plant
9/23
8. Describe how the needle-shaped leaves of
pines and firs are adapted to dry conditions.
There is a thick cuticle that covers each
leaf The leafs stomata are found in pits,
reducing water loss
Little surface area for evaporation
8/2/2019 Adaption of Seed Plant
10/23
9. List and give examples of the two classes
of Anthophyta.1. Monocotyledons (monocots)
- parallel leaf veins
- grasses2. Dicotyledons (dicots)
- netted leaf veins
- lettuce, maples
8/2/2019 Adaption of Seed Plant
11/23
10. Compare the life cycles of mosses, ferns, conifers,and flowering plants in terms of: dominant life cycle stage
(gametophyte/sporophyte), whether they arehomosporous or heterosporous, mechanism of gamete
transfer
Mosses gametophyte, heterosporous,sperm swim to egg
Ferns sporophyte, homosporous, wateris necessary
Conifers sporophyte, heterosporous,pollen fertilizes ovary
Flowering plants sporophyte,heterosporous, pollen fertilizes ovary
8/2/2019 Adaption of Seed Plant
12/23
11. Describe some refinements in vasculartissue that occurred during angiosperm
evolution. Conifers have tracheids which conduct
water (the early type of xylem cell)
Angiosperms also have xylem, but usevessel elements, which is a more efficientcell than the tracheids
8/2/2019 Adaption of Seed Plant
13/23
8/2/2019 Adaption of Seed Plant
14/23
12. Explain how evolution of the flowerenhanced the reproductive efficiency of
angiosperms. The ovary dropped below the petals and
sepals where the ovules are better
protected
8/2/2019 Adaption of Seed Plant
15/23
8/2/2019 Adaption of Seed Plant
16/23
13. Identify the following floral structures anddescribe a function for each: sepals, anther, petals,
stigma, stamens, style, carpels, ovary, filament
Sepals sterile leaves, enclose budPetals sterile, aid in attracting pollinatorsStamen produces pollenCarpel evolved from seed-bearing leaf rolled into tubeStigma part of carpel that is sticky and receives the
pollenOvary protects ovules which develop into seedsFilament
stalk of stamenAnther terminal sac of stamen where pollen is
producedStyle leads to ovary
8/2/2019 Adaption of Seed Plant
17/23
14. Describe four commonly recognizedevolutionary trends in floral structure found
in various angiosperm lineages.1. The number of floral parts have become
reduced
2. Floral parts have become fused together3. Symmetry has changed from radial to
bilateral
4. The ovary has dropped below the petalsand sepals where the ovules are betterprotected
8/2/2019 Adaption of Seed Plant
18/23
15. Define fruit and explain how fruits aremodified in ways that help disperse seeds.
Fruit a ripened ovary that protects dormantseeds and aids in their dispersal; some fruits (likeapples) incorporate other floral parts along with
the ovary Dispersal techniques
- wind dispersal (dandelions)
- burr-like fruit that cling to animal fur
- edible fruit whose seeds go through thedigestive tract of the animal and end up elsewhere
8/2/2019 Adaption of Seed Plant
19/23
16. Diagram the generalized life cycle of anangiosperm, identify which structures are haploid,and explain how it differs from the life cycle of a
pine.1. Pollen lands on a sticky stigma2. Pollen grain germinates on stigma by growing a
pollen tube down the style of the carpel
3. Reaches ovary and pollen tube grows through itsmicropyle and discharges 2 sperm into embryosac
4. Double fertilization occurs when one sperm
unites with the egg to form the diploid zygote;the other fuses with 2 nuclei in the embryo sacscentral cell to form a triploid endosperm
5. After double fertilization, the ovule maturesinto a seed, and is ready for dispersal
8/2/2019 Adaption of Seed Plant
20/23
8/2/2019 Adaption of Seed Plant
21/23
17. Explain how an angiosperm seed differsfrom that of a pine.
Pine seeds have old and new sporophyteand gametophyte incorporated into the
seed itself Angiosperm seeds have fruits that help
disperse the seeds and the fruit is usuallythe endosperm (3n)
8/2/2019 Adaption of Seed Plant
22/23
18. Explain why paleobotantists have difficultypiecing together the origin of angiosperms and
describe some current theories on how flowering
plants may have evolved.
Angios have a relatively sudden appearance inthe fossil record there are no clear links toancestors
Theories:
1. Angios originated where fossilization wasunlikely
2. Angios evolved and radiated relatively abruptly(punctuated equilibrium)
- perhaps angios evolved from seed ferns, anextinct group of unspecialized gymnosperms
8/2/2019 Adaption of Seed Plant
23/23
19. Explain how animals may have influencedthe evolution of terrestrial plants, and vice
versa. It is a consequence of interdependence
Coevolution reciprocal evolutionaryresponses among two or more interactingspecies; an adaptive change in one speciesis in response to evolutionary change in theother species