Plant Diversity and Life Cycles

Plant Kingdom Characteristics

1)Multicellular

2)Eukaryotic

3)Cell Walls

4)Autotrophic

Question:

What adaptations were needed for plants to live on land?

1)Absorb nutrients from surroundings

2)Prevent water loss

3)Dispersal (of offspring) on land

Charyophyte (Green Algae)

Homology to modern plants:1. Chlorophyll B & Beta Carotenes2. Chloroplasts have grana3. Biochemical – Cell Wall Similarities4. Mitotic Processes5. Sperm Structure6. DNA

Cuticle

All plants undergo a life cycle that takes them through both haploid and diploid generations. The multicellular diploid plant structure is called the sporophyte, which produces spores through meiotic (asexual) division. The multicellular haploid plant structure is called the gametophyte, which is formed from the spore and give rise to the haploid gametes. The fluctuation between these diploid and haploid stages that occurs in plants is called the alternation of generations.

Plant Life Cycle:

Alternation of Generations

Vascular TissueVascular tissue is composed of xylem and phloem, which function in the transport of water and dissolved substances.

Xylem - Conduct water and dissolved minerals• Support

Phloem - Conduct food and other organic substances

Vascular Versus Nonvascular Plants

Transport system

Can grow tall

Cannot survive without water

No transport system

Grow close to the ground

Can go dormant during drought

Need light

photosynthesize

Take a deep breath in and then let it out. Breathing to you is a very natural function that you usually do without even thinking about it. When you breathe, you are taking in oxygen and releasing carbon dioxide.

Plants 'breathe' too, but they do it through tiny openings in leaves called stomata (singular: stoma).Stomata open and close to allow the intake of carbon dioxide and the release of oxygen.

Bryophytes

3 Groups of Bryophytes

1)Moss

2) Liverworts

3) Hornworts

Pteridophytes

Pteridophytes are a phylum of plants.

They are the vascular plants (those having xylem and phloem tissues) that reproduce by releasing spores rather than seeds, and they include the highly diverse true ferns and other graceful, primarily forest-dwelling plants.

There are about eleven thousand different species of pteridophytes, making them the most diverse land plants after the flowering plants (angiosperms).

Pteridophytes

3 Groups of Pteridophytes

1) Ferns

2) Horsetails

3) Club moss

Gymnosperm

Gymnosperms are seed-bearing vascular plants, such as cycads, ginkgo, yews and conifers, in which the ovules or seeds are not enclosed in an ovary.

The word "gymnosperm" comes from the Greek word “gymnospermos”, meaning "naked seeds".

Gymnosperm seeds develop either on the surface of scale or leaf-like appendages of cones, or at the end of short stalks.

4 Groups of Gymnosperm1) Ginkgo

2) Gnetophytes

3) Cycads

4) Conifers

Angiosperm

Angiosperm, any member of the more than 300,000 species of flowering plants (division Anthophyta), the largest and most diverse group within the kingdom Plantae.

Angiosperms represent approximately 80 percent of all the known green plants now living.

The angiosperms are vascular seed plants in which the ovule (egg) is fertilized and develops into a seed in an enclosed hollow ovary.

The ovary itself is usually enclosed in a flower, that part of the angiospermous plant that contains the male or female reproductive organs or both.

Angiosperm

2 Categories of Angiosperm1) Monocot 2) Dicot

A comparison of monocots and dicots

The embryo of a monocot Has a single cotyledon (one embryonic seed

leaf )

Figure 38.8c

(c) Maize, a monocot. Like all monocots, maize has only one cotyledon. Maize and other grasses have a large cotyledon called a scutellum. The rudimentary shoot is sheathed in a structure called the coleoptile, and the coleorhiza covers the young root.

Scutellum(cotyledon)

Coleoptile

Coleorhiza

Pericarp fusedwith seed coat

Endosperm

Epicotyl

Hypocotyl

Radicle

The embryo of a dicot Has two cotyledon (two embryonic seed leaves

)

Figure 38.8a

(a) Common garden bean, a eudicot with thick cotyledons. The fleshy cotyledons store food absorbed from the endosperm before the seed germinates.

Seed coat

Radicle

Epicotyl

Hypocotyl

Cotyledons

The flower is the defining reproductive adaptation of angiosperms                        Flowers are made up of four types of modified leaves sepals, petals, stamens, and carpels.                                    a.  Stamens are the male reproductive organs  b.  Carpels are female reproductive organs  

The structure of a flower.

A fruit is a mature ovary                                   Protect dormant seeds. Fruit aids in seed dispersal.                     - Wind dispersal                     - Attachment and transportation                     - Consumption – berries contain seeds to be

passed in feces 

Fruit adaptations that enhance seed dispersal

Fruits are classified into several types Depending on their developmental origin

Figure 38.9a–c

Simple fruit. A simple fruit develops from a single carpel (or several fused carpels) of one flower (examples: pea, lemon, peanut).

(a) Aggregate fruit. An aggregate fruit develops from many separate carpels of one flower (examples: raspberry, blackberry, strawberry).

(b) Multiple fruit. A multiple fruit develops from many carpels of many flowers (examples: pineapple, fig).

(c)

Pineapple fruitRaspberry fruitPea fruit

Stamen

Carpel(fruitlet) Stigma

Ovary

Raspberry flower

Eachsegmentdevelopsfrom thecarpel ofone flower

Pineapple inflorescence

Stamen

CarpelsFlower

Ovary

StigmaStamen

Ovule

Pea flower

Seed

Angiosperms dominated the earth at the end of the Mesozoic era                        The spread of angiosperms represents the transition from Mesozoic to Cenozoic Angiosperms and animals have affected one another’s evolution                        Coevolution is the mutual influence on the evolution of two different species interacting with each other and reciprocally influencing each other’s adaptations.                                    e.g., Pollinator-plant relationships

Plants and Human Welfare

Agriculture is almost totally dependent on angiosperms. Plant diversity is a non-renewable resource.                        Many medicines are obtained from plant materials.  

Deforestation is an international practice

Deforestation in the United States

Fragmentation of a forest ecosystem

A sampling of medicines derived from plants