Plant evolution and Diversity Flashcards
Exam 2
Timeline of plants
Algae-> bryophytes-> Ferns->gingkoes-> confers->cycads->angiosperms
Tree of plant evolution
ligen- wood in plants act like bones to support
land colonization-lead to metabolism
sporopollenin- fungi
Total #of plant species?
400,000
how many angiosperms ?
350,000
how many conifers?
1,000
How many ferns and horsetails?
15,000
How many mosses?
23,000
How many hotspots are there in the world?
34 hot spots, an area where their is a lot of biodiversity, may contain endemic species
California and hotspots
California is considered a hotspot , there are 3,500 plant species and 60% are endemic
One endemic species from California?:
Coastal redwood tallest tree
title and name of plants
Common name, scientific name, (scientist name), (plant name)
Adaptations for life on land
-water transportation (vascular system)
-true roots/root tissue
- a cuticle to prevent drying
-stomata for gas exchange
-Apical meristem (directed growth)
-Alternation of generations
-specialized organs for disposal (spores)
Different generations in plants
there are two alternation multi cellular phases in plants
Gametophte
is a haploid (n) stage, has one set of chromosomes
Sporophyte
the diploid (2n) stage. produces asexual spores develops from zygote and has double chromosomes
Mosses
15,000 species
- simple plants
- no vascular system
-no true roots
- life cycle dominated by gametophyte
Ferns
12,000 species
-can grow tall
- have vascular tissue
- have real roots and leaves
- life dominared by sporophtyte
seed plants (2 and differences)
gymnosperms - naked seed
angiosperms- covered seed
Heterospory
Male spore- part of pollen ( microspores)
female spore- eggs (macrospores)
Seed
consists of an embryo and its food supply surrounded by protective coat
Morphology of a seed
gymno- unisexual cones
angio- flowers
Conifers
cone bearing gymnosperms
serotinus - fire open up cones to release seeds trapped inside cones
