heterotrophs: take in O2, release CO2 during cellular respiration

autotrophs: take in CO2, release O2 during photosynthesis

-Autotrophs also do respiration (release CO2 and use O2) but in smaller amts than what they use/release during photosynthesis

-at night, though, they need more Ow then what they release

Atmosphere (dry air) % of important gasses

78% N₂

21% O₂

< 1% CO₂

other gases (trace amts)

CO₂, very soluble

O₂ not very soluble

High temperature (O₂)

small, warm tidal pool, in burrow, at night (both animals and plants use up O₂)

-no circulation of other water

gas exchange across a membrane: diffusion

unicellular / small / flat (kelp) organisms, each cell is in contact with surrounding medium, no problem with gas exchange

-such organisms don't need special gas exchange organs

-lots of exposure to environment

-intracellular spaces

-low metabolism (b/c don't have to move, hunt, maintain body temp etc.)

all cells must have acces to...

thick defensive covering / impermeable covering (i.e.)...

-i.e. cuticle, feathers, hide

-makes it difficult for O₂ to diffuse through to cells / inhibit gas exchange

-need a non-scaly, non-waxy gas exchange organ

need an internal transport system or circulatory system to deliver O₂ to their internal tissues

-also need special gas exchange organ with high SA

Metabolic Rate (MR) determines...

-plants

-ectotherms (cold blooded, don't control body temp)

-endotherms (warm blooded, maintain a narrow range of body temp)

how fast O₂ is used up and therefore, how fast it must be supplied to tissues

-ectotherms have low MR

-endotherms have high MR

1. respiratory surface of adequate dimensions for the mass of the organism (folded, branced, filamentous)

2. in contact with internal transport system

3.must lack scales, exoskeleton, fur etc..

4.must be moist

5. must be kept ventilated

gas exchange organ requirments

2.in contact with internal transport system

must be highly vascularized

-i.e. gills are red because many blood vessels

gas exchange organ requirements

3. must lack scales, exoskeleton, fur etc.

-typically unprotected, thin, and fragile (so gas xchnge can happen)

-usually protected by being internalized (lungs) or surrounded by something that still allows water flow (gills)

Gas exchange organ requirements

4. must be moist

-if not moist, diffusion can't happen

-can't lose too much water, so internalization is good for terrestrial organisms

-in aquatic environment, organisms may lose ions (salts) to fresh water or lose body heat (if endoderm)

-aquatic mammals breathe air, don't lose heat through gills (because don't have them)

-no complete endotherms breathe water  (have gills?)

Gas exchange organ (G.E.O.) requirements

5. Must be kept ventilated (so constant source of oxygen)

G. E. O. uses up O₂ in surrounding area, so must be able to circulate O₂ so that it is always in contact with organ

-terrestrial/lunged animals: use muscles to breathe in air

-crabs use modified appendeges to move water across gill

-fish either swim constantly or open mouth to pump water across gills

type of gas exchange systems (see page 6, bottom slide of gas exchange slides)

NONE

 gasses diffuse directly through cell membrane

i.e. in unicellular organisms

type of gas exchange systems (see page 6, bottom slide of gas exchange slides)

CUTANEOUS

blood vessel very close to skin, diffusion of gasses through skin and through blood vessels

-i.e. animals in moist environment, skin must be moist for diffusion

-earthworms

type of gas exchange systems (see page 6, bottom slide of gas exchange slides)

PAPULAE / RESPIRATORY TREE

these exemplify evagination - projection to medium to allow more gas exchange

-both found in echinoderms

usually in multicellular aquatic organisms

-evaginated exchange structures

-vary in structure

-usually highly vascularized

-aquatic insect larvae have many different types of evaginations (gills)

-evaginated structures bad in terrestiral environment because of water loss

animals that have gills

-aquatic insect larvae

-bivalves (clams, oysters, scallops)

-crustaceans

-fish

highly folded

use cilia to draw water (O₂) and food particles in

highly folded, subdivided to compose huge SA for exchange

-no scales cover gills, very thin, highly vascularized

-water enters mouth, buccal pump to move it across gills and out

-gills covered by operculum

see top slide on page 9 of gas exchange slides

what is the filament?

water flowing in one direction transfers oxygen to blood moving in other direction

-opposite flow maintaina diffusion gradient that enhances the transfer of oxygen

-gills can remove up to 90% of oxygen dissolved in water.

exposed, not covered

-need to pump in water

must be constantly in motion to force water through gills

-some other fish are like this too

gill like structure

-found in arachnids

-evaginated into open body cavity

-for terrestrial animals, high risk of dessication

simple gills that increase surface area

-projections outside of body (evagination)

-covered by epidermis

-oxygen and carbon dioxide diffuse across

-echinoderms

-terrestrial arthropods, insects, arachnids

-terrestrial arthropods have thick cuticle for protection and to prevent water loss, high MR, especially those that fly

-spiracles

-trachea

-tracheoles

opening to outside of body in tracheal system (arthropods)

-closed by valves or flaps when not breathing to reduce water loss

singular is trachea

-narrow tubes that branch out from spiracles into the rest of the body

-part of tracheal system (arthropods)

many smaller cranches that carry air to the individual cells: no active cell >1mm from tracheole

part of tracheal system

invaginated, localized (limited to particular region of organism)

-highly vascularized

-snails and higher vertebrates (reptiles, amphibians, some fish, birds, mammals)

trace air from outside to alveoli

from larynx to thoracic cavity

-epithelial cavity ciliated: carry foreign particles and mucus away from lungs

what the trachea branches into

-goes into both lungs

-enclose bronchioles and alveoli

grape-like cluster of air-sacs

-gas excahange occurs across alveolar surface

-alveoli lining 1 thin cell thick, surrounded by capillaries