BIOL II Lecture Exam 2 Plants Intro to Structure and Life Cycles

Characteristics of Lands plants

• Multicellular, photosynthetic eukaryotes

• Almost all terrestrial and immobile

• Haploid (1n) and a diploid (2n) adult life stages

vascular tissue, seeds, flowers, fruits

not all plants have

• roots, leaves, produce flowers, fruits, or seeds, have pipes (vascular tissue) to transport water and food around the body

• Key characteristics that distinguish different groups:

1. shoot system

2. roots

2 “organ systems”

1. stems and leaves; photosynthetic

2. water and mineral uptake; anchor plants to ground; storage of photosynthesis products as starch

dermal

Plant tissues: protective skin

vascular

Plant tissues: transport

ground tissue

Plant tissues: photosynthesis, storage, and support

Meristems

Plant tissues: immortal cells that can produce any type of plant tissue (the plant “stem cells”

cuticle

Conservation of water is a key challenge for terrestrial organisms. All plants have a waxy ____ that covers the outer cells and limits water loss

stomata

pores on the bottom of leaves; surrounded by guard cells

Xylem

Vascular Tissue: tubular, dead cells that are used to move water and minerals up from roots; also provide structural support

Phloem

Vascular Tissue: living tubes; move sugars

Apical meristems

Meristem cells: responsible for grown in length of stems

Lateral meristem

Meristem cells: responsible for growth in width of stems

ploidy

number of chromosomes sets in a nucleus

mitosis

making exact copies of the cell (xeroxing)

• plants for gametes by

Meiosis

dividing the number of chromosomes sets in half (2n—> 1n)

• humans form gametes

1. Gametes fuse to form a diploid zygote (a baby sporophyte)

2. Sporophyte produces haploids spores by meiosis

3. spores grow into gametophytes

4. gametophytes produce gametes via mitosis

Plants alternate between 2 adult life stages: gametophyte and sporophyte. Explain the steps

reproduce

Plants do not use sperm to

Non Vascular

Is this vascular or nonvascular? Sporophytes are small, sporophyte must be attached to gametophyte to survive

• gametophyte dominant

Vascular

Is this vascular or nonvascular? Gametophytes are small and must be attached to sporophyte to survive

Non vascular plants

• no vessel for transport or support

• no roots to take up water and nutrients

• reproduction relies on swimming sperm

• Ex: liverworts and hornworts

Mosses

• most common no vascular plants

• green portion we see most readily is the gametophyte

• short lived sporophyte sprouts from and is dependent on gametophyte to survive

Vascular Seedless Plants

• vessels, a key innovation

• transport of water and nutrients

• support

• ability grow higher

• sporophytes and gametophytes can survive independently of one another

• reproduction still requires liquid water for swimming sperm

Ferns

• 12,000 species

• true roots, stems, and leaves

• spores travel long distances via wind

1. sporophyte produces haploid by meiosis

2. spores grow into a small gametophyte

3. sperm swim to egg

4. diploid embryo develop into sporophyte

Fern life cycle

Vascular Seed Plants

• reproduction does not rely on liquid water

• no more swimming sperm!

• pollen, the male gametophyte, travels by wind or via animals to the female gametophyte

• seeds can stay i a dry “sleeping” or dormant state for long periods of time

• special vessels help transport water long distances

Seeds

• dormant (resting stage), embryonic sporophyte

• protected by seed coat

• contain energy for growth in a triploid tissue called endosperm

Xylem

transports water and minerals UPWARDS from the roots (one direction)

Phloem

transports sugars in any direction, depending on need of plant

Gymnosperms

• no fruit or flowers

• cones are the reproductive organs

• female cones produce female gametophytes

• males cones produce male gametophytes

• rely on wind for pollination

Angiosperms

• most plants are angiosperms

• only plants with flowers or fruits

• female gametophytes are very small (7 cells)

• unlike all other plants, two sperm are involved in reproduction (double fertilization)

• 1 sperm (n) fertilizes egg (n) to make zygote (2n)

• 1 sperm (n) fertilizes a special cell (n + n) to produce endosperm (3n)