The Evolution of Plants Flashcards
What was needed for photosynthetic plants to move into land?
The evolution of chloroplasts
What is the Primary endosymbiosis derived from?
Plantae
First Clades to branch off after primary endosymbiosis?
Aquatic (algae)
Three key characteristics of the evolution of land plants:
Protected embryos, vascular tissues, and seeds
Ancestor of Plantae
Unicellular, similar to modern glaucophytes
Chloroplasts retain:
Peptidoglycan between membranes (as cyanobacteria)
Key synapomorphy of land plants:
Embryo that is protected by tissue.
Land plants are also called:
Embryophytes
Ten major clades:
Liverworts
Mosses
Hornworts
Lycophytes
Vascular plants
Tracheophytes, called tracheids (7 clades)
Nonvascular plants:
Some have conduction cells, but no tracheids
Classifications of Land Plants:
- Nonvascular Land Plants
- Vascular Plants
- Seed Plants
Land Plants develop
- Transport systems
- Structural support
- New ways to disperse gametes and progeny.
Adaptations of Land Plants
-Cuticle
-Stomata
-Gametangia
-Embryos
Pigments and Spores
Cuticle
Waxy coating that slows water loss
Stomata
Closable opening that regulate gas exchange and water loss
Gametagia
Organs that enclose gametes and prevent them from drying out
Embryos
Young plants contained within a protective structure
Pigments
Protect against UV radiation
Spores
With thick walls containing a polymer that prevents drying and resists decay
Land plants have alternation of generations:
- Multicellular diploid stage and multicellular haploid stage
- Gametes produce by mitosis
- Spores produced by meiosis
- Spores develop haploid organisms.
Diploid zygote:
Develops by mitosis and cytokinesis
Multicelluar diploid plant is called :
sporophyte
Spores develop into
Gametophyte, multicellular haploid plant
Gametophyte produces
Haploid gametes
Fusion of gametes produces:
Diploid Zygote, which then develops into sporophyte
Nonvascular Plants
Liverworts, mosses, hornworts
Charateristics of nonvascular plants:
- Live in moist habitats
- Small
- No vascular system to transport water
Liverworts
- Green
- Sporophyte attached to gametophyte
- Can reproduce asexually or sexually
Mosses
- Stomata-important for gas exchange and water retention
- Cells called hydroids which die and leave a channel through water can move.
Hornworts:
- Sporophytes look like small horns.
- Cells have one chloroplast
- Sporophyte
- Symbiotic relationships with cyanobacteria and fix nitrogen.
Nonvasular plants, gametophyte is:
Photosynthetic
What does the sporophyte depend on:
Gametophyte
Where are Gametes produced:
Gametangia (antheridia and archegonia)
Sperm must:
Swim or be splashed by water to reach the egg
What must be present for reproduction
Water
Vascular system consists:
Tissues for transport of water and materials
How did evolution help Vascular tissue:
Allowed plants to spread to new environments and diversify
Xylem conducts:
Water and minerals
Phloem conducts:
Products of photosynthesis
Tracheid:
Evolved in sporophytes and critical for invasion of land.
Tracheid includes;
Transport, the lignin provides support and allowing taller growth, which means more sunlight and disperse spores.
Vascular plants also developed:
Branching
What does branching do:
Spore production
Sporophyte of a vascular plant
Independent of the gametophyte
Invasion of land by vascular plants:
Made environment more hospitable to animals
What moved to land after vascular plants
Arthropods, vertebrates, and animals
When did trees appeared:
Devonian
When did trees dominate:
Carboniferous, when huge club mosses, horsetails, and tree ferns
What transformed into coal
Buried plant material