Plant Kingdom cont.Plant Kingdom cont.

WHAT'S A PLANTWHAT'S A PLANT

Plants are members of the kingdom plantae.  Plants are Plants are members of the kingdom plantae.  Plants are photosynthetic multicellular eukaryotes photosynthetic multicellular eukaryotes - or - or PHOTOAUTOTROPHSPHOTOAUTOTROPHS. . What about the venus flytrapWhat about the venus flytrap??

Cell walls are made of Cell walls are made of CELLULOSE CELLULOSE - the material that bacteria and - the material that bacteria and protists in our small intestine digest for us.  Cellulose is a kind of protists in our small intestine digest for us.  Cellulose is a kind of complex sugar or polysaccharide.complex sugar or polysaccharide.

Although cellulose plays an important role in structural support in Although cellulose plays an important role in structural support in the cell walls of plants, cellulose is found in other forms - such as the cell walls of plants, cellulose is found in other forms - such as cotton.cotton.

The green of plants comes from their The green of plants comes from their photosynthetic pigments photosynthetic pigments ((chlorophyll a & bchlorophyll a & b) )

LIFE CYCLE OF PLANTSLIFE CYCLE OF PLANTS The life cycle of plants has two different phases.  This is called; The life cycle of plants has two different phases.  This is called;

ALTERNATION OF GENERATIONSALTERNATION OF GENERATIONS.  In this alternation of .  In this alternation of generations, the plant takes turns undergoing mitosis and meiosis to generations, the plant takes turns undergoing mitosis and meiosis to produce haploid (n) and diploid (2n) gametes.produce haploid (n) and diploid (2n) gametes.

The The diploid (2n) phase is called the diploid (2n) phase is called the sporophyte sporophyte - or spore - or spore producing plant.  The producing plant.  The haploid (n) phase is called the haploid (n) phase is called the gametophyte gametophyte - - or gamete producing plant.or gamete producing plant.

    The spores are haploid (n) and produced thru meiosis in the The spores are haploid (n) and produced thru meiosis in the

sporophyte plant - each spore can grow into a new plant; the sporophyte plant - each spore can grow into a new plant; the gametophyte!gametophyte!

A gamete is a reproductive cell produced by mitosis and fuses A gamete is a reproductive cell produced by mitosis and fuses during fertilization with another gamete to produce a new individual - during fertilization with another gamete to produce a new individual - the diploid sporophyte. the diploid sporophyte.

Alternation of GenerationAlternation of Generation

WHAT A PLANT NEEDSWHAT A PLANT NEEDS

SUNLIGHTSUNLIGHT

WATER & MINERALSWATER & MINERALS

GAS EXCHANGEGAS EXCHANGE

MOVEMENT OF WATER & NUTRIENTS MOVEMENT OF WATER & NUTRIENTS

HISTORYHISTORY Plants didn't exist for most of the Earth's history.  Life was mainly Plants didn't exist for most of the Earth's history.  Life was mainly

found in the oceans, lakes and streams.found in the oceans, lakes and streams.     Only after photosynthetic prokaryotes (cyanobacteria) and algae put Only after photosynthetic prokaryotes (cyanobacteria) and algae put

oxygen in the atmosphere, did the conditions on Earth become oxygen in the atmosphere, did the conditions on Earth become favorable for other forms of life to evolve and therefore, favorable for other forms of life to evolve and therefore, to move onto land.to move onto land.

The first plants are thought to have evolved from plantlike-protist, The first plants are thought to have evolved from plantlike-protist, the green algae.  "From these pioneers, several major groups of the green algae.  "From these pioneers, several major groups of plants evolved." (Miller, 555)plants evolved." (Miller, 555)

1. Mosses and their relatives1. Mosses and their relatives 2. The other lineage gave rise to all the other plants found today.2. The other lineage gave rise to all the other plants found today.

Botanists divide plants into four major groups depending on three Botanists divide plants into four major groups depending on three main characteristics: water-conducting tissue, seeds, & flowers. main characteristics: water-conducting tissue, seeds, & flowers.

Plant cladogramPlant cladogram

BRYOPHYTESBRYOPHYTES "In the cool forests of the northern woods, the "In the cool forests of the northern woods, the

moist ground is carpeted with green.  When you moist ground is carpeted with green.  When you walk, this soft carpet feels spongy.  Look closely walk, this soft carpet feels spongy.  Look closely and you will see the structure of this carpet - and you will see the structure of this carpet - mosses.mosses.

    Mosses and their relatives are generally called Mosses and their relatives are generally called

bryophytesbryophytes, or nonvascular plants.  Unlike all , or nonvascular plants.  Unlike all other plants, these organisms do not have other plants, these organisms do not have vascular tissues, or specialized tissues that vascular tissues, or specialized tissues that conduct water and nutrients." (Levine, 556)conduct water and nutrients." (Levine, 556)

Groups of bryophytes: mosses, liverworts, and Groups of bryophytes: mosses, liverworts, and hornworts hornworts

Mosses (bryophytes)Mosses (bryophytes)

BryophytesBryophytes

SEEDLESS VASCULAR PLANTSSEEDLESS VASCULAR PLANTS Ferns, club mosses, and horsetails Ferns, club mosses, and horsetails Because bryophytes can only transport water from cell to Because bryophytes can only transport water from cell to

cell, their height and overall size were limited to a few cell, their height and overall size were limited to a few centimeters.  Around 420 m.y.a., something remarkable centimeters.  Around 420 m.y.a., something remarkable happened.  The little mosses were joined by plants that happened.  The little mosses were joined by plants that were up to a meter tall.were up to a meter tall.

The first vascular plants had a new type of cell that was The first vascular plants had a new type of cell that was specialized to conduct water. TRACHEIDS.  This was a specialized to conduct water. TRACHEIDS.  This was a revolutionary adaptation in the plant kingdom.revolutionary adaptation in the plant kingdom.

These cells are key in xylem - a water transport system These cells are key in xylem - a water transport system that carries water up the plant from the root.  And that carries water up the plant from the root.  And phloem - which transports solutions of nutrients and phloem - which transports solutions of nutrients and carbohydrates produced by photosynthesis. carbohydrates produced by photosynthesis.

Club mosses (bryophytes)Club mosses (bryophytes)

FERNSFERNS

SEED PLANTS: Gymnosperms SEED PLANTS: Gymnosperms (cones) (cones) & &

Angiosperms Angiosperms (flowering plants)(flowering plants) "Whether they are acorns, pine nuts, dandelion seeds, or kernels of "Whether they are acorns, pine nuts, dandelion seeds, or kernels of

corn, seeds can be found everywhere.  Seeds are so common that corn, seeds can be found everywhere.  Seeds are so common that their importance may be overlooked.  Over millions of years, plants their importance may be overlooked.  Over millions of years, plants with a single trait - the ability to form seeds - became the most with a single trait - the ability to form seeds - became the most dominant group of photosynthetic organisms on land." (Levine, 564)dominant group of photosynthetic organisms on land." (Levine, 564)

REPRODUCTION FREE FROM WATERREPRODUCTION FREE FROM WATER

Like all plants, seed plants have an alteration of generation  life Like all plants, seed plants have an alteration of generation  life cycle.  Unlike mosses and ferns, seed plants do not need water for cycle.  Unlike mosses and ferns, seed plants do not need water for fertilization of gametes.fertilization of gametes.

Adaptations that allow plants to reproduce without water are flowers Adaptations that allow plants to reproduce without water are flowers and cones.and cones.

PollenPollen: male gametophyte / : male gametophyte / SeedSeed: embryo of a living plant that is : embryo of a living plant that is encased in a protective covering and surrounded by food. encased in a protective covering and surrounded by food.

GYMNOSPERMS GYMNOSPERMS - CONE BEARERS- CONE BEARERS

These are the most ancient surviving seed These are the most ancient surviving seed plant.  This group includes the plant.  This group includes the gnetophytes, cycads, ginkgoes, and gnetophytes, cycads, ginkgoes, and conifers.conifers.

These plants all reproduce with seeds that These plants all reproduce with seeds that are exposed - are exposed - gymnosperm means naked gymnosperm means naked seed.seed.

Gnetophytes: Gnetophytes: about 70 present day about 70 present day species exist.species exist.

GnetophytesGnetophytes

CycadsCycads

Cycads: Cycads: beautiful palm-like plant that beautiful palm-like plant that reproduce with large cones.  Huge forests reproduce with large cones.  Huge forests of cycads thrived when dinosaurs roamed of cycads thrived when dinosaurs roamed Earth.  Today only nine genera exist.Earth.  Today only nine genera exist.

CycadsCycads

GinkgoesGinkgoes

These plants were common when the These plants were common when the dinosaurs existed, but today there is only dinosaurs existed, but today there is only one species left.  Carefully cultivated in one species left.  Carefully cultivated in China.China.

Gynkgo (living fossil)Gynkgo (living fossil)

ConifersConifers

Conifers: Conifers: more than 500 known species. more than 500 known species.  This group includes the pines, spruces,  This group includes the pines, spruces, firs, cedars, sequoias, redwoods, junipers, firs, cedars, sequoias, redwoods, junipers, and yews.  Some conifers like the and yews.  Some conifers like the bristlecone, can live for up to 4000 years. bristlecone, can live for up to 4000 years.  Other species like the giant redwoods,  Other species like the giant redwoods, can grow to more than 100 meters in can grow to more than 100 meters in height.  Most conifers are evergreens - height.  Most conifers are evergreens - that is, they retain their leaves throughout that is, they retain their leaves throughout the year.the year.

Coniferous forestConiferous forest

ANGIOSPERMS ANGIOSPERMS - FLOWERING PLANTS- FLOWERING PLANTS "...First appeared about 135 m.y.a...  Angiosperms "...First appeared about 135 m.y.a...  Angiosperms

develop unique reproductive organs known as flowers. develop unique reproductive organs known as flowers.  In general, flowers are an evolutionary advantage to  In general, flowers are an evolutionary advantage to plants because they attract animals such as bees, plants because they attract animals such as bees, moths, or hummingbirds, which then transport pollen moths, or hummingbirds, which then transport pollen from flower to flower.  This is much more efficient than from flower to flower.  This is much more efficient than the wind pollination of gymnosperms." (Levine, 569)the wind pollination of gymnosperms." (Levine, 569)

Flowers contain ovaries which surround and protect the Flowers contain ovaries which surround and protect the seeds.  The presence of an ovary gives angiosperms seeds.  The presence of an ovary gives angiosperms their name which mean enclosed seed.their name which mean enclosed seed.

The unique angiosperm fruit - a wall of tissue The unique angiosperm fruit - a wall of tissue surrounding the seed - is another reason for the success surrounding the seed - is another reason for the success of these plants.  Why? of these plants.  Why?

Diversity of plants todayDiversity of plants today

DIVERSITY: DIVERSITY: MONOCOTS & DICOTS (number of MONOCOTS & DICOTS (number of

seed leaves - cotyledons - in plant embryo)seed leaves - cotyledons - in plant embryo) A cotyledon is the first leaf or the first pair A cotyledon is the first leaf or the first pair

of leaves produced by the embryo of a of leaves produced by the embryo of a seed plant.  seed plant.  

There are other differences.  What are There are other differences.  What are they?they?

WOODY vs. HERBACEOUSWOODY vs. HERBACEOUS

ANNUALS (completion of one life cycle in ANNUALS (completion of one life cycle in one season) ~ wheatone season) ~ wheat

BIENNIALS (completion of one life cycle in BIENNIALS (completion of one life cycle in two seasons) ~ parsley & celerytwo seasons) ~ parsley & celery

PERENIALS (live for more than two years) PERENIALS (live for more than two years) ~ asparagus, grasses, palms, maple trees.~ asparagus, grasses, palms, maple trees.

The EndThe End