RESPIRATION

But we need to quit taxing people upon death… no taxation without respiration ~ Stephen King

What is respiration?

• The process in which organisms exchange gases with the environment

• Unicellular organisms use diffusion– Diffusion involves moving molecules from areas of high

concentration to low concentration • Larger organisms have specialized organs for respiration • 2 types

– aerobic- uses oxygen– anaerobic – doesn’t use oxygen

How does respiration happen at the cellular level?

• Cells break down glucose into CO2 and water– Equation: C6H12O6+O2 = CO2+H2O

• Photosynthesis is the chemical opposite of respiration– Equation: CO2+H2O = C6H12O6+O2

• Adaptations are structures that increase an organisms chances of ________ and __________.

• Examples include: lungs; gills; trachea and spiracles; and, in some organisms, skin

survivingreproducing

How do lungs work?

• Sponge-like elastic organs that exchange gases between body and air of many land dwelling creatures– Few marine animals have lungs

such as dolphins and whales• Usually in pairs in the chest• Air moves through branched

tubes that become smaller and smaller

• Tiniest branches of tubes end in balloon-shaped sacs with thin walls called alveoli

How does oxygen get to the rest of the body?

• Alvioli are surrounded by capillaries where blood picks up oxygen AND blood transfers CO2 released by the body’s cells– This occurs by diffusion

• Oxygen is delivered to body by blood

• O2 and CO2 are between avioli and blood by simple diffusion– This is also the method in

which the gases are exchanged between cells and blood

Assignment!

• Lung coloring sheet • Due tomorrow• Materials:– Coloring pencils or crayons– Worksheet

What are gills and how do they work?

• Specialized tissues containing many blood vessels that can take in oxygen dissolved in water– Used by many aquatic animals– Covered by a flap of skin

• Fish take in water through their mouths

• As water flows over gills oxygen is taken in, and carbon dioxide is removed as water flows out of the gills – Happens by diffusion

How well do gills work?

• They are less efficient that lungs– Difficult to move water over

them– O2 concentration in water is low

• Some aquatic animals have special adaptations– Mollusks and clams have gills in

their body cavity allowing them to pump water over their gills

– Some crustaceans like lobsters and crabs have gills on their legs so they can walk to move water over them

What about amphibians?

• Frogs and salamanders spend the entire beginnings of life in water and depend entirely on gills– Physically move gills to move

water over them• As adults they live on land

and water and develop lungs• Many use their skin • Some frogs also use the lining

of their mouth for gas exchange

Do land animals use other methods?

• Some use skin only – Thin skinned and small– Skin must stay moist– Ex. Earthworms secrete mucus

and live underground and oxygen in soil diffuses through its thin skin into capillaries; carbon dioxide diffuses out

– Other examples of animals that use their skin for respiration:• Amphibians• Segmented worms • Mollusks• Some arthropods (insects)

How do insects exchange gases?• Arthropods (insects) use

a network of tubes within their body called trachea

• Trachea deliver oxygen and pick up carbon dioxide directly to tissues

• Trachea are connected to the outside of the body using tiny openings in the exoskeleton called spiracles

How do plants exchange gas?

• Plants take in carbon dioxide and remove oxygen through photosynthesis

• At night, plants take in oxygen for cellular respiration

• Plants do BOTH photosynthesis and cellular respiration

• Exchange gas through tiny openings called stomata– Gas moves between stomata and cells

via diffusion – Land stomata are usually under leaves

in the epidermis

How do plants keep from drying out?

• Guard cells control the size of stomata– Help maintain homeostasis, or balance in

the cell• Gases exchanged are:

– Carbon dioxide - in – Oxygen - out– Water vapor – out

• Usually plants open stomata in the morning

• When do you think desert plants open theirs? Why?

• Land plants usually have stomata on the bottom of their leaves. Where do you think aquatic plants stomata are? Why?– Some plants have roots adapted to take in

oxygen also

Assignment!

• Leaf anatomy coloring worksheet• Due tomorrow• Materials:– Colored pencils or crayons– Worksheet