Communication: Visual Communication Flashcards
What is the cornea?
cornea
transparent to admit light; refracts light to help form an image on the retina
What is the sclera?
sclera
the white of the eye, a tough coat of fibres; protects the eyeball against mechanical damage, maintains shape of eyeball
What is the choroid?
choroid
a membrane containing pigment and blood vessels; nourishes retina and prevents internal reflection
What is the retina?
retina
contains light-sensitive receptor cells connected to sensory neurones; detects light
What is the iris?
iris
a pigmented muscular structure; contracts and dilates to adjust the amount of light entering the eye
What is the lens?
lens
a flexible transparent structure which allows light to enter the rear of the eye; refracts light to allow fine focusing of an image onto the retina
What is the aqueous humor?
aqueous humor
a watery fluid; maintains the shape of the eye
What is the vitreous humor?
vitreous humor
a jelly-like fluid; maintains the shape of the eye
What is the ciliary body?
ciliary body
contains muscles; supports the lens and alters the shape of the lens
What is the optic nerve?
optic nerve
consists of bundles of sensory neurons; transmits impulses generated in the retina to the brain
identify the limited range of wavelengths of the electromagnetic spectrum detected by humans and compare this range with those of other vertebrates and invertebrates
The electromagnetic spectrum consists of waves of varying wavelengths. These waves include visible light, infra-red radiation and ultraviolet radiation. Blue-green light (500 nm) is the most effective wavelengths for humans. Either side of this wavelength in the red and ultraviolet areas are less effective in humans but are used by other organisms.
Type of animal Name of animal Part of electromagnetic spectrum detected Wavelengths detected Vertebrate Human visible 700-400 nm
Rattlesnake
infra-red and visible
850-480 nm
Japanese dace fish ultraviolet and visible as low as 360 nm Invertebrate Honeybee ultraviolet and visible 700-300 nm
Mantis shrimp
ultraviolet and visible
640-400 nm
What is the conjunctiva?
conjunctiva
continuation of the epidermis of the skin; protects the cornea at the front of the eyeball against friction
use available evidence to suggest reasons for the differences in range of electromagnetic radiation detected by humans and other animals
Focus on comparing the electromagnetic radiation detected by humans, some insects and some other animals. Make sure that you analyse the evidence to suggest reasons for the differences between these animals.
A table like the one below is an effective tool to assist you to gather and present information. Well-designed tables assist you to identify useful information. Compare the range of electromagnetic radiation detected to aspects of the organisms life such as its diet, how it obtains it food, where it lives. For example, an animal that hunts in the dark such as a pit viper would have a better chance of catching prey if it could detect the heat coming off a small mammal. Animals (like the deep-sea angler) that live in the depth of the sea have no available light and use bioluminescence to attract prey.
Type of animal Name of animal Electromagnetic spectrum used Reasons
Vertebrate Human
visible
Active during the day uses colour for perception of objects
Rattlesnake
infra-red and visible
Active at night hunts in dark burrows
Hummingbird
visible
Can detect flowers from over a kilometre away
Invertebrate
Honeybee
ultraviolet and visible
Can detect ultraviolet markings on flowers and uses polarised light for navigation
Mantis shrimp
ultraviolet and visible
Can perceive many more colours and escape predation in the well lit waters were it lives
