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Tissues in Every Plant

• Dermal Tissue

• Vascular Tissue

• Ground Tissue

Dermal Tissue

• outer layer of plant

• includes epidermis in non-woody plants and periderm of woody plants

Function: prevents water loss, protects against pathogens, facilitates gas exchange

Vascular Tissue

• Xylem (water transport) and Phloem (sugar transport)

• forms stele in roots and vascular bundles in stems and leaves

Function: long distance transport and structural support

Ground Tissue

• tissues that are neither dermal nor vascular

• includes pith (internal to vascular tissues) and cortex (external to vascular tissues)

Function: photosynthesis, storage, support

Parenchyma

Ground tissue.

Cells: Thin-walled living cells

Location: leaves, cortex and pith of stems and roots

Function: photosyntheis and other metabolic functions

Collenchyma

Ground Tissue.

Cells: Irregularly thickened living cells

Location: leaves, cortex of stem in young plants

Function: flexible support

Sclerenchyma

Ground tissue.

Cells: Thick, dead-at-maturity cells, secondary cell wall with lignin

Location: around vascular bundles

Function: rigid support

Xylem

Cells: Thick, dead-at-maturity, secondary cell wall with lignin

Location: in vascular bundles

Functions: rigid support

Phloem

Cells: living, interconnected cell walls (no lignin), sieve plates

Location: in vascular bundles

Function sugar transport

Indeterminate Growth

Plants grow indefinitely from meristems.

Apical Meristems

Primary growth (length). Found at root and shoot tips.

Lateral Meristems

Secondary growth (thickness). Found in vascular and cork cambium.

Plant Body: Monocots

Plant Body: Eudicot

Vascular Cambium

Responsible for secondary growth. Adds layers of vascular tissue (secondary xylem) aka wood and secondary phloem.

Most of thickening is due to secondary xylem.

Cork Cambium

Responsible for secondary growth. Replaces epidermis with thicker, tougher periderm.

Secondary Xylem

Wood.

Secondary Phloem

What traits distinguish land plants from algae?

1. Alternation of Generations

2. Multicellular, Dependant Embryos

3. Walled Spores of Sporangia

4. Apical Merristems

Alternation of Generations

Life cycle of plants alternating between haploid gametophytes (n) and diploid sporophytes (2n)

Multicellular, Dependant Embryos

Zygote develops inside female gametophyte, providing protection and nourishment.

Walled Spores from Sporangia

Spores protected by sporopollenin; prevents dessication (drying out).

Apical Meristems

Regions of active cell division that allow plants to grow from roots and tip.

What helped the transition to land for land plants?

Traits were developed that prevented dessication, promote reproduction, and grow stronger.

Cuticle

Waxy layer covering epidermis. Minimizes water loss and protects against microbial attacks.

Mychorrizae and Land Plants

Fungi and early land plants had associations. Fungi helped with mineral absorbance before true roots were developed.

Groups of Land Plants

• Vascular Plants

• Non-Vascular Plants (Bryophyta)

Vascular Plants

Have a specilized system (xylem and phloem) which transport water and nutrients. Divided into seed plants and seedless.

Non-Vascular Plants

No vascular tissues or system, no lignin.

Divided into 3 phyla:

• Hepatophyta - liverworts

• Bryophyta - mosses

• Anthocerophyta - hornworts

Dominant gametophyte.

Stomata

Pores in land plants that regulate gas exchane and manages water loss by closing/opening.

Hepatophyta

A phyla of Non-Vascular Plants (Bryophytes). Does not have a cuticle or stomata.

Bryophyta

A phylum of non-vascular plants (bryophyta). Has a cuticle and stomata.

Lignin

A polymer found in cell walls of plants. Provides structure and support.

Why cannot non-vascular plants grow very tall?

• No vascular system to transport water and minerals; they rely on diffusion for water transport.

• No vascular tissue for structural support.

Ecological Importance of Mosses

Mosses form peat bogs which store carbon and help regulate climate.

Groups of Vascular Plants

• Seed plants

• Seedless plants

Traits in Vascular Plants (but not in non-vascular)

• Dominant sporophyte generation

• Vascular Tissue

• Roots and leaves

Basic Structure of a Seed

• Embryo

• Nutrient Supply

• Seed Coat

Function of a Seed

• protection and nourishment to embryo

• allows for dormancy and delayed germination

• allows for dispersal and survival through harsh conditions

Groups of Vascular Seed Plants

• Gymnosperms (naked seedplants)

• Angiosperms (flowering plants)

Gymnosperms

A group of seeded vascular plants (naked seed plants)

4 phylum:

1. Ginkgophyta

2. Cyadophyta

3. Gnetophyta

4. Coniferophyta

Ginkgophyta

Only 1 surviving species. Ginkgo biloba.

Coniferophyta

• Largest phylum of gymnoperms.

• Includes firs, pines, and redwoods.

• Needle or scale-like leaves

Cyadophyta

Resembles palm trees.

Gnetophyta.

Diverse group of shrubs.

Gymnosperm’s Adaptation to Land

• needle-like leaves for water retention

• thick cuticle

• pollen eliminates need for water based fertilization

Phyla of Seedless Vascular Plants

• Monilophytes

• Lycophytes

Reproduces via spores.

Monilophytes

• Includes club mosses, spike mosses, and quillworts

• Have microphylls

Lycophytes

• ferns, horsetails, whiskferns

• Have megaphyll

Megaphyll

Complex leaves with branched veins.

Microphyll

Simple leaves with single vein.

Phylum of Angiosperms

Phylum Anthophyta (flowers and fruits)

2 General Categories of Angiosperms

• Monocots

• Eudicots

Monocots

• Parallel leaf venation

• 1 cotelydon

• fibrous root system

• Pollen shape

• Flower parts in multiples of 3

• scattered vascular bundles

Eudicots

• netlike leaf venation

• 2 cotelydon

• taproot system

• Pollen thing

• Flower parts in multiples of 4 or 5

• Ring-arranged vascular bundles

Distinguishing Features of Animals

• Nutritional mode

• Cellular Organization

• Development

Nutritional Mode of Animals

Ingestive heterotrophs. Consumes other organisms or organic molecules and digests with enzymes.

• carnivores, herbivores, omnivores, detrivores

Cellular Organization of Animals

Multicellular eukaryotes.

No cell walls but have structural proteins (collagen)

• unique to animals - muscle and nerve cells

Development of Animals

Embryonic development

1. clevage - rapid mitotic cell division

2. blastula formation - hollow ball of cells (blastula) forms

3. gastrulation - blastula invaginates, forming gastrula with distinct embryonic layers

Common Ancestor of Animals

Choanoflagellates.

• similar genes

• collar cells only found in animals, not plants or fungi

Bilateral Symmetery

“a line straight down the middle”

• leads to cephalization

Cephalization

Concentration of sensory structures in the head; promotes active movement.

Radial Symmetry

“like a pie”

• allows immobile or drifting animals to interact with their environment from all directions.

Diploblastic

2 germ layers:

• Ectoderm (outer) - gives rise to outer body covering

• Endodem (inner) - forms digestive tract lining

Ex. cnidarians

Triploblastic

3 germ layers:

• Ectoderm (outer) - outer body covering

• Mesoderm (middle) - forms muscle and most internal organs

• Endoderm (inner) - forms digestive tract lining

Ex. all bilaterians

Coelomates

• have a true coelom (body cavity fully lined with mesoderm)

Ex. annelids, chordates

Pseudocoelomates

• body cavity partially lined with mesoderm

Ex. nematodes

Acoelomates

• lack a body cavity, restricting organ movement

Ex. platyminthes

Major Clades of Bilaterians

• Deuterostomia - echinodermata, chortata

• Lophotrochozoa - mollusca, annelida

• Ecdysozoa - arthropoda, nematoda

Phylum Porifera

• lack tissues, but have some specialized cells

• no symmetry

• sessile (not moving throughout its life)

• filter feeders - filters water through body to capture food particles

Ex. sponges

Phylum Cnidaria

• 2 tissue layers - contractile and nerve tissues

• radial sym.

• no organs

• diploblastic

• has cnidocytes (stinging cells)

• gut with one opening (gastrovascular cavity)

• 2 forms: polyp form and medusa form

Ex. jellyfish, coral, anemone

Cnidaria: Polyp Form

• cylinder or tube-like

• upward mouth

• sessile

Cnidaria: Medusa Form

• bell-shaped

• downward mouth

• freeswimming - pulsing or drifting

Phylum Platyminthes

• bilateral sym.

• acoelomate

• flattened body

• gut with one opening (gastrovascular cavity)

• organ systems

• free-living or parasites (parasites don’t have digestive system)

Ex. flatworms

Phylum Rotifera

• bilateral sym.

• pseudocoelomate

• complete digestive system (gut with 2 openings)

• organ systems

Ex. rotifer

Phylum Annelida

• bilateral sym.

• coelomate

• organ systems

• segmented body

• closed circulatory system

• complete digestive system

• segmentation differentiates them from nematodes and flatworms

Phylum Mollusca

• body (generally shelled) with: foot, visceral mass, and mantle

• bilateral sym.

• organ systems

• complete digestive system

• coelomates

• classes: gastropods, cephalopods, bivalves

Phylum Nematoda

• bilateral sym.

• cylindrical body

• pseudocoelomate

• complete digestive system

• free-living or parasites

• exoskeleton

Phylum Arthropoda

• most species- and lifestyle-diverse animal phylum

• flexible chitinous exoskeleton

• versatile, jointed appendages

• highly developed sensory organs

• segmentation

• metamorphasis

• complete digestive tract

• bilateral sym.

• open circulatory system

Protostomes

Mouth develops from blastopore.

Ex. mollusks, annelids

Deuterostomes

Anus develops from blastopore.

Ex. echinoderms, chordates

Phylum Echinodermata

• bilateral sym in larvae, radial sym. in adults

• calcareous exoskeleton

• water vascular system

• complete digestive system

• coelomates

• deuterostomes

Ex. starfish. urchins, seacucumbers

Phylum Chordata

• notochord, pharyngeal slits, dorsal nerve cord, post anal tail

• bilateral sym.

• super huge and lots of subphylums

Vertaebrates

• muscular post-anal tail

• notochord

• dorsal, hollow nerve cord

• pharyngeal slits or clefts

Oldest Lineages of Vertebraes

Hagfish and Lamperys.

• lack jaws

• no backbone

• rudimentary backbone made of cartilage

• bottom dwelling scavengers

• most are parasitic that latch and pierce with tongue to feed

Osteichthyes

“bony fish”

• buoancy control with swim bladder

• flat bony scales

Chondrichthyes

“cartilage fish”

• skull and jaws

• tooth-like scales

• predators (sharks) and bottom feeders (rays)

Osteichthyes vs. Chondrichthyes

bony skeleton vs cartilaginous skeleton

Types of Osteichthyes

Ray-finned and Lobed-fin

Ray-finned Osteichthyes

• bony skeleton

• bony rays

Lobed-finned Osteichthyes

• lobed fins

• rod-shaped bones in pectoral and pelvic fins surrounded by thick layer of muscle

Tetrapods

“4 feet”

• in place of pectoral and pelvic fins, limbs with digits

• limbs support weight on land

• muscles produce force to move

• head and neck

• lung breathing

Origin of Tetrapods

• lobed finned fishes in oxygen poor water could use their lungs to breathe instead

• they moved by propping themselves up on their fits and walking in water

• wrists, ribs, and necks are ancestral to tetrapods

Amphibians

• most basal group of tetrapods; vertebrates

• semi-terrestrial

• rely on moist skin for gas exchange

Metamorphasis:

• aquatic tadpole with gills to semi-teresstrial adult with lungs

Amniotic Egg

• pivotal for vertebrae colonization of land

• allowed vertebrates to reproduce away from water bodies, reducing reliance on aquatic bodies for reproduction

• Structure: protective shell with specialized membranes

  • Amnion, Chorion, Allantois, Yolk sac

Amnion

Encloses embryo in fluid-filled cavity, cushioning against mechanical shock.

Chorion

Facilitates gas exchange between embryo and external environment.

Allantois

Involved in waste storage and respiration.

Yolk Sac

Provides nutrients.

Classes of Amniotes

• Birds (Aves)

• Mammals (Mammalia)