Bio 158: Lecture 5

Bio 158 Form and Function Lecture 5

Plant Structure: One of the systems

Shoot system: stems and leaves.

• Allows: Photosynthesis, reproduction

Plant Structure: Another one of the systems

Root system: anchors plant, absorbs water and ions

Three types of plant tissue

dermal tissue = protective exterior
ground tissue = storage, photosynthesis
vascular tissue = conducting substances

Descriptive of Plant Tissue: Dermal Tissue

• Forms a protective interface with the environment

• Contains a waxy cuticle

• Specialized cells:

  • guard cells: help regulate opening of stomata

  • trichomes: hairlike outgrowth on stem of leaf that protect plant

  • root hairs: hairline extension that increased surface area of root

Descriptive of Plant Tissue: Ground Tissue

Different cells that work for storage, photosynthesis, secretion, support, and protection

Plant Tissue: Ground Tissue Type Parenchyma

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Plant Tissue: Ground Tissue Collenchyma

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Plant Tissue: Ground Tissue Sclerenchyma

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Descriptive of Plant Tissue: Vascular Tissue

Xylem: Tissue that conducts water and dissolved minerals

Phloem: Tissue that conducts carbohydrates

Plants: Root Structure

Prop roots -

Epiphytic roots -

Pneumatophores -

Water storage root -

Buttress root -

Plants: Modified Stems

Each serves a special purpose:
Bulbs: storage for next year’s leaves
Rhizome: horizontal stems that grow underground
Runner: on surface + similar to rhizome
Tuber: accumulation of carbohydrates
Tendrils: support climbing plants
Cladophyll: flattened stems

Plants: Leaves

Principal sites of photosynthesis
Veins: vascular bundles

Vertebrate body: 4 levels of organization:

1) cells
2) tissues
3) organs
4) organ Systems

Vertebrate body: 4 types of tissues

1) epithelial
2) connective
3) muscle
4) nerve Muscle

Descriptive of Vertebrate body Tissue: Epithelial tissue

• Forms a protective barrier

• Not just our skin

• Simple epithelium: one cell thick

• Stratified: two to several layers thick

Descriptive of Vertebrate body Tissue: Connective Tissue

Key characteristic: cells spaced widely apart and all have abundant extracellular matrix

Loose connective tissue:

• cells scattered in a matrix with a lot of ground substance

• most common type in vertebrates

• includes fat tissue

Dense connective tissue:

• tightly packed collagen fibers

• forms tendons and ligaments

Special connective tissue: unique cells (cartilage, bone, and blood)

Descriptive of Vertebrate body Tissue: Muscle Tissue

Actin and myosin: proteins that make up muscle

3 types:

Smooth muscle: occurs in organs

• powers rhythmic, involuntary contractions commanded by the central system

Skeletal muscle: attached to bones by tendons

• powers walking, lifting, talking, and all other voluntary movement

Cardiac muscle: Striated cells that are interconnected

• highly interconnected cells; promotes rapid spread of signal initiating

Descriptive of Vertebrate body Tissue: Nerve Tissue

Neuron: contains cell body, dendrite, and axon
Produce and conduct electrochemical events (impulses)
Neuroglia: support and insulate neurons
Three types of nerves:

• sensory

• motor

• interneurons

Type of Nerve: Sensory

• receive info about body’s condition and external environment

• send impulses from sensory receptors to the central nervous system

Type of Nerve: Motor

• stimulate muscles and glands

• conduct impulses out of central nervous system toward muscles and glands

Type of Nerve: Interneurons

• integrate info

• conduct impulses between neurons w/in nervous system

Plant Movement

• Response to stimuli

• limited to see or spore dispersal

Animal Movement: Skeletons

3 types of skeletal systems in animals
2) Exoskeleton
3) Endoskeleton

Type of skeletal systems Animal: Hydrostatic skeleton:

• worms, cnidarians, mollusks

• fluid-filled central cavity surrounded by muscles

Type of skeletal systems Animal: Exoskeleton

• arthropods

• chitin surrounds the outside of the body

Type of skeletal systems Animal: Endoskeleton

• vertebrates (bone) and echinoderms (calcite)

• rigid internal structures that provide framework

Vertebrate Movement: Muscles, Tendons, + Bones

• Tendons connect muscles to bones

• Muscles contract

• Tendons transfer the force to the bones

• Which bone(s) move depends on mass + resistance from surroundings

Vertebrate Movement: Fishes

Primary force slowing movement is frictional drag
Body movement involves moving body/fins

Vertebrate Movement: Terrestrial

• Gravity is main challenge

• Walking: body raised above ground and body moved by pushing against ground with legs

• Arthropods: 6 or more legs, Vertebrates: 2 or 4 legs

• Some insects and vertebrates leap

Vertebrate Movement: Air

• Flight is convergent evolution: evolved independently 4x (insects, bat, pterosaur, bird)

• All vertebrate fliers have modified forelimbs into wings

• Propulsion by pushing down against air, which provides lift to body

Invertebrate Movement: Cnidarians

• Hydrostatic skeleton

• Main body (bell) has a ring of muscle cells in the epithelium

  • These rhythmically contact to propel animal

  • Water moves out from gastrovascular cavity, pushing animal up

What new cell types did the common ancestors of Cnidarians and all bilateral animals evolve?

• muscle

• nerve

Invertebrate Movement: Nematoda

• Hydrostatic skeleton

• Muscles beneath the epidermis extend longitudinally

• Pulling of muscles causes a wriggling motion

Invertebrate Movement: Annelida

• Body is composed of ringlike segments

• The inside fluid gives each segment rigidity: hydrostatic skeleton

  • move by contracting circular and longitudinal muscles against this skeleton

  • alternating contractions and confining to specific segments lets worm move in complex ways

Invertebrate Movement: Arthropoda

• Rigid exoskeleton is broken into segmented plates

• At plate boundaries the exoskeleton is very thin to allow for movement

• Appendages specialized for walking, running, swimming

• Some have wings which are layers of exoskeleton