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Strategies of early plants adapting to land
Live near water, tolerance to desiccation, stay small in size, mechanisms against UV radiation
Adaptations to terrestrial life
1. Alternation of Generations life cycle
2. Apical meristem in roots and shoots
3. Waxy cuticle
4. lignin in vascular tissues
5. Sporopollenin
waxy cuticle
prevents water loss
Apical meristems
Specialized zones of growth found at the tips of plants
Lignin
substance in vascular plants that makes cell walls rigid
sporopollenin
a layer of durable polymer that prevents exposed zygotes from drying out
First terrestrial plant strategies
LIVE NEAR WATER
develop mechanism to protect from UV Rays
develop tolerance to desiccation
humid enviros
stay small
What is the dominant stage of the seedless plant life cycle
Sporophyte stage
Bryophytes
A moss, liverwort, or hornwort; a nonvascular plant that inhabits the land but lacks many of the terrestrial adaptations of vascular plants.
What type of plant is a bryophyte
A non vascular seedless plant
What plant is the closest living relative to earliest terrestrial plants
Bryophytes
Characteristics of bryophytes
No vascular tissues, limited in size, gametophyte stage dominant, homosporous, thallus and rhizoids
gametangia
Sex organ that produces gametes in plants
Where does the gametangia grow from in bryophytes
The thallus
What are the 3 types of bryophytes
mosses, liverworts, hornworts
Thallus
The body of a plant-like organism that is not divided into leaves, roots, or stems.
Rhizoids
A thin, rootlike structure that anchors non vascular plants to the ground and absorbs water and nutrients.
Is non vascular seedless plant fertilization water dependent
Yes because male gametes swim
How does fertilization of non vascular seedless plants occur
Sperm is released from antheridia and swim to the archegonia
Antheridia
Structures in plants that produce male gametes
Archegonia
Structures in plants that produce female gametes
What is the dominant stage of a vascular seedless plant
Sporophyte
Is the fertilization of seedless plants water dependent
Yes
What is the conductive vascular tissue of seedless plants
Xylem, phloem
Xylem
vascular tissue that carries water upward from the roots to every part of a plant (water conducting tissue)
Phloem
Complex tissue which acts as a transport system for soluble organic compounds within vascular plants ( food conducting tissue)
Do non vascular seedless plants have roots, stems or leaves
No
Do vascular seedless plants contain roots stems and leaves
Yes
Why did vascular seedless plants adapt to have leaves
Greater photosynthetic efficiency
Types of leaves
microphylls and megaphylls
microphylls
spine shaped leaf with single strand of vascular tissue, only in lycophytes
megaphylls
larger leaves with a highly branched vascular system
sporophylls
modified leaves that bear sporangia
Where can sporophylls be found
In both microphylls and megaphylls
sori
clusters of sporangia
strobili
cone-like structures formed from groups of sporophylls
sporangia
multicellular organs that produce spores
Are seed plants sporophyte of gametophyte dominant
Sporophyte dominant
What happens to the gametophyte of a seed plants
Gametophyte become microscopic structure inside the sporophyte
ploidy level of sporophyte
diploid (2n)
Ploidy level of gametophyte
haploid (n)
What do sporophytes (zygote) produce?
haploid spores by meiosis
Antheridium produces what?
sperm
Archegonium produces what?
eggs
Are zygote diploid or haploid
Diploid
How do seed plants reproduce without water
The evolution of pollen meant seeds were no longer dependent on water for reproduction because pollen could travel by wind rather than water
What do gametophytes produce?
gametes by mitosis
Disadvantages of terrestrial plants
threat of desiccation, UV rays, need structural support, plant reproduction is water dependent, zygote is water dependent
Advantages of terrestrial plants
•Sunlight is abundant
•Carbon dioxide is abundant
•No competitors for resources
•No predators
Heterospory
produces both microspores (male gametophytes) & megaspores (female gametophytes)
How does heterospory appear in seed plants
Megaspores which develop into female gametophyte and microspores which develop into male gametophyte
How does fertilization work for seed plants
When pollen lands on female gametophyte a pollen tube will grow towards the egg
Gymnosperms
A plant that produces seeds that are exposed rather than seeds enclosed in fruits
examples of gymnosperms
conifers, cycads, and ginkgophytes
What protects the naked seeds (gymnosperms)
Woody leaves called sporophylls
tracheid
hollow plant cell in xylem tissue with thick cell walls that resist pressure
Monoeicious
male and female flowers on the same plant
Diocous
Plants have male flowers (cones) on one plant and female flowers (cones) on a different plant
How are gymnosperms pollinated?
by wind
Angiosperms
flowering plants that produce seeds in fruit
What is the most dominant species of plant on earth
Angiosperms
Adaptations of angiosperms
flowers and fruits
Why did angiosperms adapt to have fruit
For embryo protection and dispersal
Why did angiosperms adapt to have flowers
Pollination and protection
Are angiosperms monoecious or dioecious
both perfect flowers are monoecious and imperfect flowers are dioecious
How are angiosperms pollinated
Vio wind insects and mammals
Function of vessel cells in xylem tissue of angiosperms
Efficient at conducting water
Male sex organ of angiosperms
Stamen (androecium)
What do stamen produce
Microspores which develop into pollen
Female sex organ of angiosperms
Carpel (gynoecium)
Function of carpel
Contains megasporangia
What is the end product of double fertilization of angiosperms
A diploid zygote and triploid endosperm
How does reproductive mutualism work with angiosperms and animals
Pollination and dispersion of seeds
