Flow of Energy and Matter in Ecosystems

• Energy- capacity to do work.– all life on earth possess some kind of energy,

without it life is not possible.

Photosynthesis

How are Producers structurally adaptedto Photosynthesis?

• leaves are the basic requirement of plants to undergo the process.

• 2 Major structures:A. External structure

- manner on which the leaves are arranged on the stem( Phyllotaxy).( alternate, opposite or whorled)-main part of a leaf is called a leaf blade/Lamina.(Chlorophyll- a pigment that makes leaf green)

• petiole- stalks; were leaves are attached; is connected to one or major veins.

• Types of leaves:A. Simple- one piece of LaminaB. Compound- when lamina is divided into small piece called leaflets.

a.1 pinnately compound- leaflets are arranged along the entire length of an extended axis called rachis.

a.2 palmately compound- if the leaflets are attached on contracted rachis at the tip of the petiole.

Internal Structure

• at the cross section, the leaf has 3 major parts:A. upper and lower surface layers of cells and the epidermisB. Vein made of Vascular tissues.C. middle layer( Mesophyll)

• epidermis- protective layer( cutin- waxy material)

• lower epidermis- contains the stomata( use for exchange of gas and loss of water in the form of vapor- transpiration)

• Upper xylem- vascular tissues; transport of water

• Lower Phloem- vascular tissue; food transport in form of sucrose.

• Mesophyll- where photosynthesis mostly occurA. Palisade mesophyll- Upper portion;

compactly arranged, cylindrical cell with numerous choloroplasts.

B. Spongy Mesophyll- loosely arranged, irregularly shaped cells, big spaces but few choloplasts.

How do producers harness light energy?

• the sun furnishes the energy needed in Photosynthesis. Plants are provided with green pigments called CHLOROPHYLL that capture this radiant energy and convert it into CHEMICAL energy of food.

Nature of Light• Light- a small part of the vast continuous radiant energy

that comes from the sun.- it exhibits both particle and wave properties.- as particle it consists of units of energy called photons.- as an electromagnetic energy in waves.- distance between waves is wave length.- the longer the wavelength the less energy it contains, the shorter the wavelength the more energy it contains.- it is visible with wavelengths between 390 to 760 nanometers.-when this visible wave passes through a prism, each wavelength bends a particular angle. White light is then seperated into its constituent band of colors of red, orange, yellow green, blue, indigo and violet.- when light strikes an object, it maybe absorbed, reflected or transmitted.

• absorbed light- transform to another form.– if its not absorbed its either reflected or

transmitted.( is seen as the color of the object)

– opaque objects( reflects light)– Transparent objects( transmit light)– Cholorophyll doesnt absorb light, thus leaves

are green because, being opaque, they scatter or reflect light in all direction.

• Answer Quick thinking pp 105 and 106.