TOWARD UNDERSTANDXNQ ECOSYSTEMS
9
where a(h) is the spectral absorptivity of the organism surfaoe to r d a -
tion of wavelength A.
An example of the spectral absorptivities, a(h), of various organisms
aa a function of the wavelength over a significant portion of the 8 p -
trum is shown in Fig. 1. It is evident that each of theae organisms,
Mimdus leaf, human hand, white cat, Stellar Jay, and Pika, are ewh
coupled to the incident radiation to a very different degree. It is not a
particulmly simple matter to determine the intermtion of an organism
I
I
0 4
0 6
0 8
10
12
1-4
1.6
1.8
2.0
2.2
Wavelength (microns)
FIG. 1. The absorptanoe of the organisni surface versus wavelength. ( 8 ) stellar Jay
fathers (back); (b) Pika fur (beck); ( c ) Human hand (palm); (d) White cat fur; (e)
Mimulw cardinalis leaf (upper surface).
with the incident radiation fluxes, but the absorptivity must be measured if one is to understand the amount of radiation absorbed. The
spectral absorptivity is measured by means of an integrating sphere
attachment to a spectrophotorneter. Whether it is a bird, lizard, insect,
mammal, or plant the spectral absorptivity of the surface, or of various
parts of the surface, is an essential factor for understanding the interaction with the incident radiation. Some organisms can vary the absorptivity of their surface by changing the pigment composition of the
integument or by changing the orientation and density of hair or fur.
The spectral properties of plant leaves are discussed in detail by Gates
et al. (1965), and by Gates et al. (1966). An object which reflects rcsdiation very well like a mirror is essentially decoupled from the incident
flux of radiation and its temperature is uninfluenced by the intenaity
of radiation. An organisni which is black is atrongly coupled to the
9
where a(h) is the spectral absorptivity of the organism surfaoe to r d a -
tion of wavelength A.
An example of the spectral absorptivities, a(h), of various organisms
aa a function of the wavelength over a significant portion of the 8 p -
trum is shown in Fig. 1. It is evident that each of theae organisms,
Mimdus leaf, human hand, white cat, Stellar Jay, and Pika, are ewh
coupled to the incident radiation to a very different degree. It is not a
particulmly simple matter to determine the intermtion of an organism
I
I
0 4
0 6
0 8
10
12
1-4
1.6
1.8
2.0
2.2
Wavelength (microns)
FIG. 1. The absorptanoe of the organisni surface versus wavelength. ( 8 ) stellar Jay
fathers (back); (b) Pika fur (beck); ( c ) Human hand (palm); (d) White cat fur; (e)
Mimulw cardinalis leaf (upper surface).
with the incident radiation fluxes, but the absorptivity must be measured if one is to understand the amount of radiation absorbed. The
spectral absorptivity is measured by means of an integrating sphere
attachment to a spectrophotorneter. Whether it is a bird, lizard, insect,
mammal, or plant the spectral absorptivity of the surface, or of various
parts of the surface, is an essential factor for understanding the interaction with the incident radiation. Some organisms can vary the absorptivity of their surface by changing the pigment composition of the
integument or by changing the orientation and density of hair or fur.
The spectral properties of plant leaves are discussed in detail by Gates
et al. (1965), and by Gates et al. (1966). An object which reflects rcsdiation very well like a mirror is essentially decoupled from the incident
flux of radiation and its temperature is uninfluenced by the intenaity
of radiation. An organisni which is black is atrongly coupled to the