Plants

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Plants

• The study of plants is called Botany

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What is a plant?

• Multicellular eukaryote
• Produce their own food through photosynthesis
• Have thick cell walls made of cellulose

• Stems leaves of most have a waxy waterproof
  coating called a cuticle to prevent water loss

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Adaptations of Plants

• Preventing water loss Most fruits, leaves, and
  stems are covered with a protective, waxy layer
  called the cuticle
• The waxy cuticle creates a barrier that helps
  prevent the water in the plants tissues from
  evaporating into the atmosphere

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Adaptations of Plants

• 2. Carrying out photosynthesis The leaf, is a
  plant organ that grows from a stem and usually is
  where photosynthesis occurs
• Each plant species has unique leaves or leaflike
  structures

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Adaptations of Plants

• 3. Putting down roots Plants can take in water
  and nutrients from the soil with their roots
• In most plants, a root is a plant organ that
  absorbs water and minerals usually from the soil

• Roots anchor a plant usually in the ground
  function as storage.

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Adaptations of Plants

• Stems also can serve as organs for food storage
  and contain chlorophyll so they can carry out
  photosynthesis

• Transporting materials Water moves from the
  roots of a tree to its leaves, and the sugars
  produced in the leaves move to the roots through
  the stem
• A stem is a plant organ that provides support for
  growth.

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Reproductive Strategies

• A seed is a plant organ that contains an embryo,
  along with a food supply, and is covered by a
  protective coat.
• It also protects the embryo from drying out and
  also can aid in its dispersal

Embryo
Seed Coat
Food Supply
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Non-seeded Plants

• In non-seeded plants (mosses ferns)have spores
  that releases directly into the environment where
  they can grow into haploid gametophyte plants
• These plants produce male and female gametes

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Seeded Plants

• In seed plants, which include all conifers and
  flowering plants, sperm reach the egg without
  using a film of water
• This difference is one reason why non-seed plants
  require wetter habitats than most seed plants

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Seeds

• In seed plants, such as conifers and flowering
  plants, spores develop inside the sporophyte and
  become the gametophytes.
• The gameotophytes consist of only a few cells
• Male and female gametes are produced by these
  gametophytes

• After fertilization, a new sporophyte develops
  within a seed. The seed eventually is released
  and the new sporophyte plant grows.

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Two Main Types of Plants

• 1. Nonvascular Plants
• Does not contain Xylem Pholem.
• Receives water from osmosis diffusion
• Must grow close to a water source
• Does not have true roots, stems, or leaves

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Two Main Types of Plants

• 2. Vascular plants
• have tubes and vessels to transport water and
  nutrients (Xylem Phloem) Grass, trees,
  flowers, ferns
• Vascular plants can live farther away from water
  than nonvascular plants.

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Xylem Pholem
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Vascular Plant are divided into

• Seed Plants-flowers, pines, trees, grasses
• subdivided into
• angiosperms-flowering plants
• gymnosperms-cone bearing plants
• Seedless plants-ferns

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Nonvascular Plants

• 3 Types of Nonvascular Plants
• mosses, liverworts hornworts

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Nonvascular Plants
Moss
No true roots, stems, or leaves, must live near
water or moist environment
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Nonvascular PlantHepaticophyta Liverworts

• Small plants commonly called liverworts because
  the flattened body of the plant and it resembles
  the lobes of an animals liver
• They grow in moist environments
• They use osmosis diffusion to transport water
• Found from Artic to Antarctic
• Some found in water, others in deserts

• Most have an oily/shiny surface

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2 kinds of liverworts

• The body of a thallose liverwort is called a
  thallus.
• Found growing on damp soil

• Thallose liverwort
• have broad body that looks like a lobed leaf

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2 kinds of liverworts

• Leafy liverworts grow close to the ground and
  usually are common in tropical jungles and areas
  with persistent fog
• Their stems have flat, thin leaves arranged in
  three rowsa row along each side of the stem and
  a row of smaller leaves on the stems lower
  surface

• 2. Leafy Liverwort are creeping plants with 3
  rows of thin leaves attached to a stem

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Nonvascular PlantAnthocerophyta Hornwort

• Small Plants
• Sporophytes resembles the horns of an animal
• Nonvascular plant-grows in damp, shady habitats
• Relies on osmosis diffusion to transport
  nutrients

• Currently consisting of only about 100 species
• are similar to liverworts in several respects

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Nonvascular PlantsBryophyta Mosses

• Nonvascular plants
• Rely on osmosis and diffusion to transport
  materials
• Habitats include close to streams, rivers or
  humid tropical forest
• Limited in size (less than 5 cm tall)
• Cannot compete with vascular plants

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Mosses

• Mosses are
• More familiar than liverworts
• Small plant w/ leafy stems
• Grow in dense carpets or turfs
• Mosses have rhizoids, which help anchor the stem
  to the soil.

• Some have upright stems others have creeping
  stems that lie along the ground or hang from
  steep banks or tree branches

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Mosses

• Some mosses form extensive mats that help retard
  erosion on exposed rocky slopes
• Moses grow in a wide variety of habitats, even in
  the arctic during the brief growing season where
  sufficient moisture is present
• A well-known moss is Sphagnum, also known as peat
  moss.
• This plant thrives in acidic bogs in northern
  regions of the world. It is harvested for use as
  fuel and is a commonly used soil additive

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Non-seed Plants

• Non-seed plants are vascular plants

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Psilophyta Wisk Ferns

• Consist of thin, green stems.
• Are unique vascular plants because they have
  neither roots nor leaves
• Small scales that are flat, rigid, overlapping
  structures cover each stem.

• The two known genera of psilophytes are tropical
  or subtropical, only 1 found in U.S.

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Lycophyta Club Mosses

• Vascular plants adapted primarily to moist
  environments
• Have stems, roots, and leaves
• Their leaves, although very small, contain
  vascular tissue
• Ancestors grew as tall as 30 m and formed a large
  part of the vegetation of Paleozoic forests

• The plants of these ancient forests have become
  part of the coal that is now used by people for
  fuel.

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Club Moss

• The club moss, Lycopodium, is commonly called
  ground pine because it is evergreen and resembles
  a miniature pine tree
• Some species of ground pine have been collected
  for decorative uses in such numbers that the
  plants have become endangered

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Arthrophyta Horsetails

• Vascular plants
• They have hollow, jointed stems surrounded by
  whorls of scalelike leaves
• The cells covering the stems contain large
  deposits of silica
• About 15 species of arthrophytes exist today

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Horsetail

• Early horsetails were tree-sized members of the
  forest community. Todays arthrophytes are much
  smaller than their ancestors
• There are only about 15 species in existence, all
  of the genus Equisetum
• These plants also are called scouring rushes
  because they contain silica, an abrasive
  substance
• Most horsetails are found in marshes, in shallow
  ponds, on stream banks, and other areas with damp
  soil

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Pterophyta Ferns

• The most well-known and diverse group of non-seed
  vascular plants.
• They have leaves called fronds that vary in
  length from 1 cm to 500 cm
• The large size of fronds is one difference
  between pterophytes and other groups of seedless
  vascular plants

Although ferns are found nearly everywhere, most
grow in the tropics
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Ferns

• According to fossil records, fernsdivision
  Pterophytafirst appeared nearly 375 million
  years ago
• Ancient ferns grew tall and treelike and formed
  vast forests

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Fern Structures

• In most ferns, the main stem is underground.
  This thick, underground stem is called a rhizome.

Fronds
Rhizome
Root
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Fern Structures

• The leaves of a fern are called fronds and grow
  upward from the rhizome.

• The fronds are often divided into leaflets called
  pinnae, which are attached to a central rachis.

• The branched veins in ferns transport water and
  food to and from all the cells.
• Fern spores are produced in structures called
  sporangia

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Sorus

• Clusters of sporangia form a structure called a
  sorus (plural, sori). Sori are usually found on
  the underside of fronds but in some ferns, spores
  are borne on modified fronds

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Seeded Plants
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Cycadophyta Cycads

• Were abundant during the Mesozoic Era.
• Today, there are about 100 species of cycads
• They are palmlike trees with scaly trunks and can
  be short or more than 20 m in height
• Cycads produce male and female cones on separate
  trees

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Cones

• Cones are woody strobili scaly structures that
  support male or female reproductive structures
• Seeds are produced in female cones.
• Male cones produce clouds of pollen

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Diversity of Cone Bearing Trees

• Trees that bear cones are called gymnosperms
• Characteristics
• produce seeds in cones (pines, firs, cedars)
• needle-like leaves

Male cones produce pollen
Female cones contain seeds
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Adaptations in Coniferophyta

• The reproductive structures of most conifers are
  produced in cones.

Wing
Wing
Pollen grain
Two seeds
Spores
Ovule
Pollen sac
Male cones
Female cone
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• Evergreen confiers trees that are green year
  round photosynthesize when conditions are right
• Deciduous trees lose their leaves each fall to
  conserve water through winter conditions

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Gnetophyta Gnetophytes

• There are three genera of gnetophytes (NEE toh
  fites) and each has distinct characteristics
• 1. Gnetum (Nee tum) includes about 30 species of
  tropical trees and climbing vines

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Gnetophyta Gnetophytes

• There are about 35 Ephedra (eh FEH dra) species
  that grow as shrubby plants in desert and arid
  regions

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Gnetophyta Gnetophytes

• Welwitschia (wel WITCH ee uh) has only one
  species, which is found in the deserts of
  southwest Africa
• Its leaves grow from the base of a short stem
  that resembles a large, shallow cap

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Ginkogophyta Ginko biloba

• This division has only one living species, Ginkgo
  biloba, a distinctive tree with small, fan-shaped
  leaves
• All ginkgoes are cultivated trees, and they are
  not known to exist in the wild

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Ginkos

• Ginkgoes (GING kohs) have male and female
  reproductive structures on separate trees.
• The seeds produced on female trees have an
  unpleasant smell, so ginkgoes planted in city
  parks are usually male trees
• Ginkgoes are hardy and resistant to insects and
  to air pollution

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Coniferophyta Cone-Bearing Trees

• These are the conifers (KAH nuh furz),
  cone-bearing trees such as pine, fir, cypress,
  and redwood
• vascular seed plants that produce seeds in cones

• Species of conifers can be identified by the
  characteristics of their cones or leaves that are
  needlelike or scaly.

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Bristlecone Pine

• Bristlecone pines, the oldest known living trees
  in the world, are members of this plant division.

• Another type of conifer, the Pacific yew, is a
  source of cancer-fighting drugs.

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Anthophyta The Flowering Plants

• Commonly called the flowering plants, are the
  largest, most diverse group of seed plants living
  on Earth
• There are approximately 250 000 species
• Unlike conifers, anthophytes produce flowers from
  which fruits develop

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Diversity of flowering plants

• Flowering plants, also called angiosperms,
  produce seeds enclosed within a fruit.
• A fruit includes the ripened ovary of a flower.

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Anthophyta

• A fruit usually contains one or more seeds.
• Division has 2 classes

• Monocotyledons (mah nuh kah tul EE dunz) include
  grasses, orchids, lilies, and palms

• Dicotyledons (di kah tul EE dunz).

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Monocot Characteristics
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Dicot Characteristics
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Cotyledons

• An embryo is an early stage of development of an
  organism
• Embryos of seed plants include one or more
  cotyledons
• Cotyledons usually store or absorb food for the
  developing embryo.

Cotyledon
Cotyledons
Seed coat
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Life span of anthophyta

• 1. Annual plants live for only a year or less.
  They sprout from seeds, grow, reproduce, and die
  in a single growing season.

• Annuals form drought-resistant seeds that survive
  the winter.

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Life span of anthophyta

• 2. Biennial plants have life spans that last two
  years
• -1st year grow many leaves and develop a strong
  root system
• -Over the winter, the aboveground portion of the
  plant dies back, but the roots remain alive
• -2nd year food stored in the root is used to
  produce new shoots that produce flowers and seeds.

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Life span of anthophyta

• 3. Perennials live for several years, producing
  flowers and seeds periodicallyusually once each
  year
• They survive harsh conditions by dropping their
  leaves or dying back to soil level, while their
  woody stems or underground storage organs remain
  intact and dormant