BIOL 1543 Lecture Notes - Lecture 20: Non-Vascular Plant, Stoma, Flowering Plant
DOWNLOAD 20 - PLANTS AND FUNGI
textbook reading: 17: 1-4, 6, 8, 10, 12, 14, 17
PLANTS ARE ADAPTED TO LIFE ON LAND
500 million years ago, there was only algae growing on shore edges
this plant’s closest relative was a green agla
OPPORTUNITIES AND CHALLENGES TO LIFE ON LAND
opportunities
unlimited sunlight
abundant CO2
initially, few pathogens or herbivores (there were no land animals yet)
challenges
keeping moisture in cells
supporting bodies of water
reproduce out of water
anchor in soil
get resources from soil and air
MEETING THE CHALLENGE OF LIFE ON LAND
land plants maintain
moisture in their cells using:
a waxy cuticle
cells that regulate the opening and closing of stomata
land plants obtain
water and minerals from roots in the soil
some have vascular tissue
CO2 from the air
sunlight through leaves
stomata little holes in leaves to regulate gas exchange and water loss
reproduction and dispersals
in algae, gametes and young offspring stay in water and do not dry out
in land plants, spores and pollen grains have tough coats to protect reproductive
cells
embryos are protected by and develop inside parent plants
PLANT DIVERSITY REFLECTS THE EVOLUTIONARY HISTORY OF THE PLANT KINGDOM
four key adaptations for life on land
these distinguish the main lineages of the plant kingdom
dependent embryos are present in all plants
lignified vascular tissues mark a lineage that gave rise to most living plants
seeds are found in a lineage:
includes all living gymnosperms angiosperms
dominates the plant kingdom today
flowers mark the angiosperm lineage
PLANT EVOLUTION
PLANT DIVERSITY
nonvascular plants
brophytes seedless nonvascular plants
came about during early diversification
includes mosses
vascular plants
evolved with lignin-hardened vascular tissues
seedless vascular plants
lycophytes (club mosses)
monilophytes (ferns and their relatives)
dominated vast “coal forests”
when these plants died, they formed peat deposits that eventually formed
coal
as temperature dropped during the late carboniferous period
glaciers formed
the climate turned drier
the vast swamps and forests began to disappear
wind-dispersed pollen and protective seeds gave seed plants a
competitive advantage
seed plants