Plant  Evolu+on  and  Classifica+on  

Chapter  28  

Adapting to Land

1.  The ability to prevent water loss: cuticle- waxy protective covering (also keeps our CO2)

http://images.absoluteastronomy.com/images/topicimages/p/pl/plant_cuticle.gif

Adap+ng  to  Land  

2. The ability to reproduce in the absence of water – spores and seeds

http://static.howstuffworks.com/

http://www.nsf.gov/ http://www.wsu.edu:8080/

Spore  vs  seed  

•  A  spore  is  haploid  reproduc+ve  cell  surrounded  by  a  hard  outer  wall.    Allowed  the  widespread  dispersal  of  plant  species.  

•  A  seed  is  an  embryo  surrounded  by  a  protec+ve  coat.    Some  seeds  contain  endosperm-­‐  +ssue  that  provides  nourishment  for  the  developing  plant.    Seeds  are  more  effec+ve  for  dispersal  than  spores    – ex.  Maple  tree  seeds  

Adap+ng  to  Land  

3.  The ability to absorb and transport nutrients –   Vascular tissue – xylem and phloem

botit.botany.wisc.edu/

Vascular  Tissue    

•  Vascular  +ssue  transports  water  and  dissolved  substances  from  one  part  of  the  plant  to  another.    It  also  provides  support.  

•  Xylem-­‐  transports  inorganic  nutrients  one  way:    roots  to  leaves  

•  Phloem-­‐  carries  organic  compounds/some  inorganic  compounds  any  way,  any  where  

Classifying  Plants  

Nonvascular  vs.  Vascular  

Algal Ancestors

Reproduction by Spores

Harden Vascular Tissue

Seeds

Flowers

Nonvascular Plants

Seedless Vascular Plants

Gymnosperms Angiosperms

Nonvascular plants

•  Have neither true vascular tissue nor true roots, stems, or leaves.

•  3 phyla – Bryophyta – Heptophyta – Anthocerophyta

Vascular  Plants  

•  Vascular,  seedless  – Whisk  ferns  –  Club  mosses  

–  Horsetails  –  Ferns  

•  Vascular,  seed  –  Cycads  –  Ginkgoes  –  Conifers  –  Gnetophytes  –  Flowering  plants  

•  Monocots  

•  Dicots  

Vascular  Plants  

•  Have vascular tissue and true roots, stems, and leaves

pky7thgradescience.pbworks.com

Seedless vascular plants

•  Ferns – dominated the earth until about 200 million years ago.

Vascular Seed Plants

•  Produce seeds for reproduction – embryo with a nutrient supply

•  Have a greater chance of reproductive success

•  When conditions are right the seed sprouts, or germinates

Gymnosperms

•  4 phyla •  Produce naked seeds

– Seeds are not enclosed and protected by fruits. – Most are evergreen and bear their seeds in cones

Angiosperms •  1 phyla – produces seeds that are enclosed and

protected in fruits – called flowering plants

http://universe-review.ca/I10-22a-angiosperms.jpg

The Evolution of Angiosperms

•  In many angiosperms, seeds germinate and produce mature plants, which in turn produce new seeds, all in one growing season.

•  Gymnosperms often take 10 or more years to reach maturity and produce seeds.

The Evolution of Angiosperms

•  The fruits of flowering plants protect seeds and aid in their dispersal.

The Evolution of Angiosperms

•  Angiosperms also have a more efficient vascular system and are more likely to be associated with mycorrhizae than gymnosperms.

www.greenmanconservation.co.uk

The Evolution of Angiosperms

•  Angiosperms have an advantage by using animal pollination rather than the less-efficient wind pollination used by gymnosperms.

The Evolution of Angiosperms

•  Angiosperms are more diverse than gymnosperms, so they occupy more niches.

Aquatic

Epiphytic

Parasitic

Monocots  and  Dicots  •  Based  upon  the  number  of  cotyledons.  

•  Cotyledon:    seed  leaves  in  a  plant  embryo  

http://www.seedbiology.de/hormones.asp

www.sproutpeople.com/