Plants: An Introduction
Transcript of Plants: An Introduction
Plants: An IntroductionPlants: An Introduction
The The Plant KingdomPlant Kingdom can be viewed as having can be viewed as having
the true terrestrial plants and those that are the true terrestrial plants and those that are
““almostalmost”” true terrestrial plants.true terrestrial plants.
Outline Outline
� Key concepts
� Important roles of Plants
provide food, air (oxygen), clothing, etc.
� Comparison
� Classification:
� Evolutions
� Conclusions
Key Concepts:Key Concepts:
� The plant kingdom consists of multicelled
photoautotrophs
�Nearly all plants live on land
� Plants have structural adaptations that allow
them to photosynthesize, absorb water and
ions, and conserve water
� Land plants are reproductively adapted to
withstand dry periods
Key Concepts:Key Concepts:
� Early divergences gave rise to the bryophytes,
then the seedless vascular plants, and then the
seed-bearing vascular plants
�Gymnosperms are the seed-bearing vascular
plants and the angiosperms are also vascular
plants that bear flowers and seeds
�Angiosperms include two classes of flowering
plants
� Eudicots and Monocots
ComparisonComparison
Animals Plants
1. heterotrophic autotrophic
2. stop growing continuing growing
3. reproductive tissue reproductive tissue
present all times not present at all times
Classification Classification & Evolution& Evolution
1. Bryophytes: Non-vascular Plants
2. Seedless Vascular Plants
3. Gymnosperms: Seed-bearing Plants
4. Angiosperms: The Flowering Seed-
Bearing Plants
BryophytesBryophytes
�Mosses
�Nonvascular
�Moist habitats
mostly
� Small
�< 20 cm tall
� Simplest plants
Moss-covered rocks
Seedless Vascular PlantsSeedless Vascular Plants
�Whisk ferns,
Lycophytes,
Horsetails, Ferns
�Has vascular tissues
�Habitat
�Moist places
�Sperm needs
water to reach egg
LycopodiumPsilotum
Equisetum
FernsFerns
GymnospermsGymnosperms--Plants with Plants with ““NakedNaked”” SeedsSeeds
� Conifers, Cycads, Ginkgos, Gnetophytes
�Conifers - cones
�Pines, cypress, firs, spruces, redwoods
Gymnosperm DiversityGymnosperm DiversityBristlecone pine
A cycad’s
seed-bearing cone
Gymnosperm DiversityGymnosperm Diversity
Ginkgo Ginkgo
seeds
Ginkgo
leaf and
fossil
Gymnosperm DiversityGymnosperm Diversity
Welwitschia mirabilis– GnetophyteIt grows in hot deserts of Africa with a deep taproot. It has
one or two strap-shaped leaves that split lengthwise
repeatedly as the plant ages.
Pine treesPine trees
Angiosperms: flowering Angiosperms: flowering seed plantsseed plants
� The dominant plant form on earth (>250,000
species)
� Flowers to increase insect pollination
� Fruit to protect the seed and developing embryo until favorable germination conditions occur
� Broad leaves to increase photosynthesis during the growing season are shed during periods of cold and drought
AngiospermsAngiospermsThe Flowering SeedThe Flowering Seed--Bearing PlantsBearing Plants
� Flowers
� Coevolution with
pollinators
� Insects Bats
Birds
� Seed
�Ovary
EudicotsEudicots and Monocotsand Monocots
�Almost 180,000 Eudicots
�Cabbage and Daisies
�Flowering shrubs and trees
�Water lilies
�Cacti
�About 80,000 Monocots
�Orchids, palms, grasses,
crop plants, rice
AngiospermsAngiosperms
Evolution of PlantsEvolution of Plants
In ConclusionIn Conclusion
�Green algae probably gave rise to plants
� Trends in evolution can be identified by comparing
different lineages
�Mosses are bryophytes, nonvascular plants
� Vascular plants are adapted to land
� The seedless vascular plants include the whisk
ferns, lycophytes, horsetails, and ferns