BIOL1020 - Week 12.1

form vs function in plants

• form: structure

• function: what it does

what do plants need to survive and reproduce

• make energy (photosynthesis)

• reproduce and disperse

• water, CO2, sunlight, nutrients, roots, mates

4 main plant organs and their functions

• roots: anchor and absorbs water/nutrients

• stem: support and transport

• leaves: photosynthesis

• reproductive organs: reproduction and dispersal

main parts of a leaf and their roles

• cuticle: reduces water loss

• epidermis: protection, contains stomata

• mesophyll: photosynthesis

• air spaces: allow gas diffusion

stomata

• small pores on leaf surface

• CO2 enters, O2 and vapour exits

how does stomata control gas exchange

• guard cells control opening and closing

• when opened: CO2 enters and O and water exit

• closed: reduces water loss

secondary growth

• increase in stem thickness

• provides stronger support

• adds more vascular tissue

• caused by lateral meristems

types of root systems

• taproot: one main deep root, accesses deeper water

• fibrous roots: many thin roots, spread near surface, good for anchoring

pollination syndromes

• traits that attract specific pollinators

key traits of wind pollination

• no petals, scent, or nectar

• exposed anthers and stigmas

• feathery stigmas

key traits of animal pollination (birds and bees)

• birds:

  • bright red flowers, tubular shape, nectar deep inside, little to no scent

• bees:

  • blue/purple/yellow flowers, sweet scent and nectar, UV patterns, landing platform

key traits of fly pollination

• dark red/purple flowers

• rotting (putrid) smell

• usually no nectar

• mimics decaying material

seed dispersal importance

• colonize new areas

• increase genetic diversity

• reduce competition with parent plant

how do animals disperse seeds

• eat fruit → passed in feces

• bury seeds

• hooks/barbs attach to clothing/fur

how are seeds dispersed by wind and water

• wind: lightweight seeds, wings/parachutes

• water: buoyant seeds/fruits, float and disperse

mechanical (explosive) seed dispersal

• fruits dry and build tension

• burst open

• seeds are forcefully ejected away