Biology 11

A.MacAskill

All cells require a constant supply of:Oxygen Nutrients

All cells need to get rid of waste products:

Carbon Dioxide

Small simple animals can use diffusion to exchange gases ( O2 and C02) and receive nutrients. Ex: Sea Anemone, Flat worms

Diffusion is not sufficient for larger animals.

Larger animals require a transportation system and special gas exchange structures.

The Circulatory System is a Transportation System:

Responsible for transporting nutrients and oxygen to cells and removing wastes and carbon dioxide from cells.

(cellular respiration)

Open Circulatory System: Hemolymph is pumped by the heart into an

open cavity called the hemocoel Hemolymph bathes the organs directly with

oxygen and nutrients Muscular movements during location can help

the hemolymph circulate ex: Arthropods, Mollusks

Closed Circulation System: Blood is always contained in vessels of

different size and thickness. Blood is pumped by heart through

vessels to all parts of the body.Ex: Annelids, Chordates

Why are closed circulatory systems more efficient than open?

Single Loop Circulation System: Found in organisms with gills The heart pumps blood to the gills from

there it passes directly to the tissues before being returned to the heart.

Double Loop Circulation System:Found in organisms with lungsBlood flow has two distinct pathwaysBlood flows to the lungs or to the body from

the heart

Heart : a muscular pump to move the blood

Chambers of the Heart: Atrium: Top chamber which receives blood

from body Ventricle: Bottom chamber which sends blood

to body

Septum: A thick muscular wall which separates heart chambers

Arteries: large blood vessels that carry blood from the heart to the tissues of the body

Capillaries: extremely small blood vessels that allow for nutrients and oxygen to reach tissues and carbon dioxide and other wastes to pass from the tissues.

Veins: Blood vessels that carry blood from the tissues to the heart.

Heart comprised of two chambers: One Atrium & One Ventricle

Single loop circulation

Blood collected from the body enters the Atrium

The heart relaxes, the blood passes through a valve into the Ventricle

Contraction of the ventricle forces the blood into the capillary network of the gills.

Blood then flows to capillary network of the body.

Blood returns to the atrium. Cycle continues!

Heart comprised of three chambers:Two Atria & One Ventricle

Double loop circulation

Right Atrium receives deoxygenated blood from the body

Left Atrium receives oxygenated blood from the lungs and skin

Both atria empty into the single ventricleWhat is the problem with this?

Ventricle contracts and pumps blood to both the body and lungs

The cycle continues !

Note: Septum extends into the ventricle Why would this be beneficial compared

to the Amphibian?

Heart comprised of four chambers: Two Atrium (Right and Left) Two Ventricles (Right and Left)

Double loop circulation Complete Septum, no mixing of blood

Deoxygenated blood from the body enters the Right Atrium

Blood flows through a valve into the Right Ventricle

Deoxygenated blood flows to the lungs where gas exchange occurs

Oxygenated blood from the lungs enters the Left Atrium

Blood flows through a valve into the Left Ventricle

Oxygenated blood flows to the body where gas exchange occurs

Ectotherms are cold blooded ; not capable of maintaining a constant body temperature

Endotherms are warm blooded; capable of maintaining a constant body temperature

What are some advantages/disadvantages of being an endotherm? Advantage: Can be active and survive at low

external temperatures Disadvantage: Require high amounts of energy

(we must always eat food)

Plant Transportation System

Plants also need a transportation system:To gain nutrients and waterTo move water from the roots to the rest

of the plantTo move nutrients from the leaves to the rest of the plant

Plants are divided into two groups:Non-vascular: do not contain vascular

tissueVascular: contain vascular tissue

Plant Transportation Mechanism:

Xylem

Xylem Structure:Long hollow tube extending from the root

Is Dead Tissue

Xylem Function:Transportation of water from the roots to the rest of the plant

Walls are thick to provide structure to the stem

Plant Transportation Mechanism:

Phloem

Phloem Structure:Bidirectional flowLiving Tissue

Phloem Function:Transportation of nutrients from the leaves to the rest of the plant

Characteristics of Non-Vascular Plants

Do not have roots, stems or leaves Lack vascular tissue

This limits the size of the plant because it cannot transport water and food very far

Are small in size Depend on water for reproduction

Cannot survive in dry areas Examples: Mosses, Liverworts, Hornworts

Characteristics of Vascular Plants

Have true roots, stems, and leaves Have vascular tissue (vascular bundles):

Xylem: Transports waterPhloem: Transports nutrients

Are capable of reproduction on land

Two types of flowering plants:MonocotsDicots

Monocots- Vascular Plant

Leaf veins are parallel and extend the length of the leaf

One cotyledon: first leaf to germinate Vascular bundles: are scattered in the

stem Flower parts arranged in three’s Ex: Grass, Cattails, Lilies, and Palmtrees

Dicots- Vascular Plants Have leaves with net-like veins Leaf veins are parallel and extend the

length of the leaf Vascular bundles: arranged into a

cylinder Flower parts arranged in four’s or five’s Increase their diameter each year

Lab Time! Follow Instructions on your lab sheet.