BIOL 1011 Lecture Notes - Lecture 6: Red Algae, Embryophyte, Charophyta
Plants and the Colonization of Land
January 6, 2015
Importance of Plants:
1. Energy: food
2. Energy: fossil fuels
3. Clothing
4. Drugs, medicine
5. Ecosystem functioning
6. Biodiversity
Botany – the study of plants
• Evolution
• Ecology (community and population)
• Molecular genetics
• Mathematical modeling
• Morphology
• Anatomy
• Physiology
• Cell biology
• Systematics
• Development
Overview: Greening of Earth
• It is difficult to imagine a landscape without plants or organisms
• For more than the first 3 billion years, terrestrial surface was lifeless
• Since colonizing, plants have diversified into 290,000 living species
• Plants supply oxygen and are the ultimate source of most food eaten by land
animals
1 mm
Red algae
Chlorophytes
Charophytes
Embryophytes
ANCESTRAL
ALGA
Viridiplantae
Streptophyta
Plantae
What is a plant?
plastids
This
class
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Document Summary
Importance of plants: energy: food, energy: fossil fuels, clothing, drugs, medicine, ecosystem functioning, biodiversity. Botany the study of plants: evolution, ecology (community and population, molecular genetics, mathematical modeling, morphology, anatomy, physiology, cell biology, systematics, development. Photosynthetic eukaryotes: plants and red algae, primary endosymbiosis: non photosynthetic eukaryote engulfed, other eukaryotes photosynthetic cyanobacteria, secondary endosymbiosis: nonphotosynthetic eukaryote engulfed , cyanobacterium, green alga, red alga. Plants split from red algae around 1500 million years ago. (cid:498)oxygen revolution(cid:499) led to more photosynthesis and more plants. Features of 2 phylogeny: ancestors of land plants, charophytes are closest relatives that support both nuclear and chloroplast genes, land plants are not descended from modern charophytes but share a common ancestor. Contain: cell plate and phragmoplast, plasmodesmata, sperm structure, peroxisome enzymes, rose-shaped cellulose synthesizing complexes. Chlamydomonas is a single cell green alga without alternation of generations. A zygote delays meiosis and instead divides and grows. This process arose independently in evolution several times.