Bio 111 Lecture 6

Bio 111 Lecture 6 - Who is this BIOL 111 Organismal Biology Lecture 6 Evolution of plants colonization of land 1 Charles Darwin 2 A famous Canadian

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
1 1 Lecture 6 Evolution of plants & colonization of land 17 September 2009 BIOL 111 – Organismal Biology 2 Who is this? 1. Charles Darwin 2. A famous Canadian 3. Someone important to this lecture 4. Someone important to McGill 3 Sir William Dawson • geologist • principal of McGill (1855-1893) • discovered a fossil of an early plant (Gaspé Peninsula, 1859) – first Devonian (400 mya) plant found Psilophyton = naked plant – no roots, no leaves Psilophyton 4 Plants lecture outline 1. Colonization of land 2. Alternation of generation in plants 3. Plant phylogeny, diversity, & evolutionary innovations – Nonvascular (nonseed) plants – Vascular nonseed plants – Gymnosperms – Angiosperms (flowering plants) 5 Who is the closest ancestor to plants? 1. fungi 2. brown algae 3. green algae 4. choanoflagellates 5. animals 6 Advanced green algae are ancestors of plants. • All green algae (chlorophytes) have – photosynthesis with chlorophyll a, b – store starch – cellulose in cell walls – haploid dominant life cycle (not shared with all plants) charo- phytes
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 7 Advanced green algae are ancestors of plants. • Charophytes have – multicellular growth form – egg protected – alternation of generations • Live in marginal habitats (edges of ponds, marshes) modern charophytes 8 Colonization of land • Ordovician-Silurian (460-420 mya) • coincided with first terrestrial animals (arthropods) and fungi • challenges… – desiccation – harmful radiation – structural support – water, mineral acquisition & transport – dispersal of gametes, embryos Cooksonia (420 mya) – earliest known vascular plant 9 Early adaptations to terrestrial challenges • Avoiding desiccation: – surface protected by waxy cuticle – gametes protected in gametangia – embryo protected in embryo sac – spores protected by thick wall • UV protection – accessory pigments • uptake of water, minerals – symbioses with fungi (mycorrhizae) Cooksonia (420 mya) – earliest known vascular plant 10 Early plants dependent on water • lack transport system ( vascular system
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 10/16/2009 for the course BIOL BIOL111 taught by Professor R during the Fall '09 term at McGill.

Page1 / 8

Bio 111 Lecture 6 - Who is this BIOL 111 Organismal Biology Lecture 6 Evolution of plants colonization of land 1 Charles Darwin 2 A famous Canadian

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online