Crosscutting Concepts

1. Patterns2. Cause and Effect3. Scale, Proportion, and Quantity4. Systems and System Models5. Energy and Matter in Systems6. Structure and Function7. Stability and Change of Systems

Systems and System Models: A system is an organized group of related objects or components; models can be used for understanding and predicting the behavior of systems.

k-2: Objects and organisms can

be described in terms of their parts.

Systems in the natural world have parts that work together.

3-5: A system is a group of related

parts that make up a whole and can carry out functions its individual parts cannot.

A system can be described in terms of its components and their interactions

Structure and Function: The way an object is shaped or structured determines many of its properties and functions.

k-2: The shape and stability of

structures of natural and designed objects are related to their function(s).

3-5: Different materials have

different substructures, which can sometimes be observed.

Substructures have shapes and parts that serve functions

SKELETONS

Supporting structures for animalsProtect, support, enable movementSupport for movement and form in animals

4 typesEndoskeletonExoskeletonHydraulic skeletonCytoskeleton

How is a skeleton a system?

Has boundaries Has parts Parts work together

Function of skeletons

Support the body Shape of the body Enable movement Protection for internal organs Physiological functions

4 types of skeletons in animals

Endoskeleton Exoskeleton Hydraulic skeleton Cytoskeleton

Vertebrate skeleton• An endoskeleton – inside of the body • Functions:

– muscle attachment & movement– Protection of internal organs– Blood cell production– Calcium storage

• Living, mineralized tissue (cartilage & bone)

• Jointed• Two parts:

– axial – appendicular

All vertebrates have the same basic skeletal elements

Arms and Legs:How vertebrates move

Modifications of shape and size result in different function

Manatee

• Ribs and long bones have no marrow

• This helps them sink to bottom to feed

Exoskeletons

Stable outer shell• Found in arthropods• Made of chitin• Hard • Prevent dessication• Provide protection

Must shed exoskeleton to grow

Muscles attach on inside

• Insects and crustaceans have jointed appendages

• Muscles attach on inside surfaces of exoskeleton

Variation in size and shape provide for different functions

Hydrostatic skeletons in soft-bodied organisms

• Found in - Mollusks (e.g. snails, clams, slugs, octopus)- Worms- Tube feet of anemones

• Fluid filled cavities ringed with muscle

Movement in worms: how it worksCircular & longitudinal muscles

Elongate & contract body segments

Setae grip substrate

Jet propulsion

Japanese flying squid

Cytoskeletons –“movers and shapers”

• Proteins in form of microfilaments and microtubules in cytoplasm

• Form a 3-D meshwork• Dynamic – assemble and reassemble• Important for cell shape, movement of organelles

and materials in the cell, cell division, cell movement

• Motor proteins – cilia and flagella

Fluorescent dyes show filaments (red) and tubules (green)

Plant structural support

• Hold leaves (stems/trunk)

• Anchor to ground (roots)

• Require both flexibility and rigidity

How?

• Cell wall• Lignin• Cellulose• Wood

Cross Cutting concepts• Must observe parts before can understand them• Models are useful for studying structural systems• Understanding structure helps understand

function and vice versa• Function can be explained in terms of form and

form can be explained in terms of function• Structure and function are related through

natural selection• In biological organisms, structure is not always

optimal, but reflects the best solution available in a given lineage