Plant Diversity II
Objectives
•Examples from seed plant phyla
•Gymnosperm & angiosperm lifecycle & evolutionary importance
•Flower features that ensure pollination by different pollinators
•Factors that influence pollen germination
•Recognize fruits and their dispersal mechanisms
•Relate the structures of seed plants to their function
Introduction of the Seed Plants
Traits common to all Seed Plants
•Reduced gametophytes
•Heterospory
http://www.engineering.arizona.edu/news/story.php?id=7
•Pollen – male gametophyte
•Ovule – female gametophyte
http://www.mcb.ucdavis.edu/faculty-labs/gasser/gasser-lab.html
Definition of a Seed
Formed in a sexual cycle
Propagative organ
Embryo
Food supply
Protective coat
http://www.primarygames.com/science/flowers/facts.htm
Evolutionary Advantages of Seeds
Multicellular protective layer around embryo
Storage Supply
http://theseedsite.co.uk/seedparts.html
Diverse distribution
http://www.physorg.com/news186417173.html
http://garden.lovetoknow.com/wiki/Flower_Seeds
http://outdooredibles.com/burdock/
Gymnosperms
“naked seeds”
Reduced gametophyte – male – multinucleate pollen grain
- female – retained within the sporangium
- abiotic pollination
Can sit here for a year!
Gymnosperm Lifecycle
Gymnosperm Phyla
Coniferophyta
(both monoecious & dioecious)
Ginkgophyta
(dioecious)
http://www.uic.edu/classes/bios/bios100/labs/plantdiversity.htm
Cycadophyta
(dioecious)
(in greenhouse)
http://www.flowersgrowing.com/tag/bonsai-plant/
Gnetophyta
(dioecious)
(in greenhouse)
http://www.hcs.ohio-state.edu/hcs300/classif.htm
Figure 30.5 in book for Characteristics
http://www.funet.fi/pub/sci/bio/life/plants/gnetophy
ta/ephedraceae/ephedra/fragilis-1mx.jpg
Angiosperms
Single Phylum – Anthophyta
“Flowering” plants – most diverse and widespread –
¼ million species – 90% of all plants
Key adaptations –
Flowers – structure specialized sexual reproduction
Fruits – protect dormant seeds and aid in dispersal
Pollinators – biotic means of fertilization
Angiosperm Lifecycle
Seed structure ploidy
Fig.3 p 132
Flower
Exocarp
Mesocarp
Endocarp
Fruits
http://www.1001recipe.com/articles/delicious_and_colorful_berries/
Pericarp develops
From the Ovary wall
http://www.gardenguides.com/choosing-fruits-nuts/
Pollination Factors
abiotic Wind or water
http://www.fs.fed.us/wildflowers/pollinators/wind.shtml
Pollination Factors
biotic
insects, birds and mammals (vectors)
some have co-evolved
shape, color, and scent
Summary
Seeds
Structure
Characteristics
Gymnosperms
Characteristics
Phyla
Life cycle
Angiosperms
Characteristics
Phylum
Life cycle
Fruits
Structure
Characteristics
Types
Evolutionary Aspect – what is
it about the characteristics of
these two groups that
conferred fitness and allowed
them to be successful
Pollination – different types of
pollination and the vectors
Vocabulary
Helpful Links
Gymnosperms
Angiosperms
Germinating pollen
Double fertilization
Next Week
Plant Anatomy