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Flashcards in lecture 18 Deck (31):

body temperature

-thermoregulation is the maintenance of body temp within a tolerable range
-most of life's processes are very sensitive to body temp
-every animal species has a optimal temp range
-important to keep temp within this range
-humans: 37 degrees
-endotherms are warmed and heated by their own metabolism
-ex) humans and birds
-ectotherms gain most of their heat from the environment and other external sources
ex) amphibians and fish


heat can be exchanged with the environment in four ways

1. conduction
2. convection
3. radiation
4. evaporation



-transfer of heat in between molecules by direct contact
-heat always moves from the hotter object to the colder object



-transfer of heat by the movement of fluid across a surface



-emission of electromagnetic waves
-can transfer heat in between objects that are not in direct contact



-loss of heat from the surface of a liquid
-happens when a molecule obtains enough energy to leave the liquid and become gas


adaptation for thermoregulation

2. insulation
3. circulation
-evaporative cooling
-behavioural repsonses



-hormonal changes in cold weather boost the metabolic rate of mammals, increasing heat production
-additionally moving around more increases heat production
-shivering: contraction of skeletal muscles



-hair, feathers, or fat
-raising or fur or feathers in response to cold traps heat against the surface of the body (goose bumps: humans)



-heat loss can be controlled by the changing the amount of blood flowing to the skin surface
-blood vessels near the surface of the skin dilate and constrict
-conserves heat in the bodies trunk when necessary


evaporative cooling

-painting, sweating, and spreading saliva on bodily surfaces all act to decrease body temp
-humans sweat


behavioral responses

-migration of birds to different climates
-basking in the sun when cold or seeking shade when hot
-bathing functions to cool immediately



-animals must dispose of nitrogenous wastes
-excretion is the disposal of metabolic wastes
-nitrogenous wastes are products of protein metabolism
-ammonia is poisonous
-water soluble and easily disposed of in animals
-it is converted to urea which is less toxic and much safer to store within the body
-urea and uric acid require energy to produce



-can be sexual or asexual
-asexual reproduction results in offspring genetically identical to the parent
-allows for the production of many offspring very quickly
-binary fission: two equally sized cells are produced from one parent cell
-budding: two cells of unequal size are produced from one parent cell
-parthenogenesis: development of an unfertilized egg
-regeneration: entire body parts of some animals can be regenerated
-in humans regeneration is limited to healing and tissue repair
-liver has extensive regenerative capacity


reproduction: sexual

-sexual reproduction: fusion of haploid gametes from two parents forms a diploid zygote
-results in extensive genetic variation within offspring
-some animals exhibit hermaproditism
-both male and female reproductive organs are present on the same animals
-in humans this can sometimes occur by mistake


reproduction: external fertilization

-occurs in many fish and amphibians
-eggs and sperm are released into water for fertilization to take place
-often physical contact is not required
-timing is very important because the eggs must be ripe


reproduction: internal fertilization

-sperm are deposited within or close to the female reproductive tract and gametes unite within the tract
-an adaptation the omits the need for water
-requires copulation: sexual intercourse


nervous system: radial symmetry

-the organization of the animals nervous system correlates with form of body symmetry
-animals that are radially symmetrical:
-have web-like nervous systems
-ex) nerve net in hydra
-diffuse throughout the animal body
-no central or peripheral nervous system


nervous system: bilateral symmetry

-bilateral symmetry:
-these organisms tend to move through their environment
-requires a head with concentrated sensory organs
-two major adaptions are found within this group:
-cephalization:concentration of the nervous system st the head end
-centralization: a central nervous system(CNS) distinct from the peripheral nervous system


nervous system: vertebrate nervous system

-highly specialized
-CNS: brain and spinal cord
-PNS: peripheral nerves
-vertebrate and skull function to protect nerves



-senses are important for animal function
-guide movement
-salmon use senses to find their breeding areas
-bears use their senses to locate salmon
-collectively these senses gather info that facilitates feeding, migrating, and other behaviors
-sensory info arrives as a sensation to the brain
-how the brain interprets this info is referred to as perception
-sensory receptors:
-detect stimuli and convert the info into an action potential that is then sent to the brain
-these receptors are highly specialized to pick up stimuli and are located within sensory organs:
-eyes, nose taste buds
-the stimulus energy is transmitted into an action potential which is what will then be sent to the brain


five categories of sensory receptors

-many types of receptors can be found on the skin alone
1. pain receptors
2. thermoreceptors
3. mechanoreceptors
4. chemoreceptors
5. electromagnetic receptors


pain receptors

-detect stimuli that are considered dangerous



-detect heat or cold, monitors body temp



-respond to any changes in mechanical energy such as touch, pressure, and sound



-repsond to chemicals
-the nose and the mouth detect chemicals in the enviornment and those about to enter the body
-internal receptors detect chemicals within the body


electromagentic receptors

-respond to electricity, magnetism, and light (detected by photoreceptors)



-a number of different eyes types have developed in vertebrates
1. simple eye:
-these are cups that sense light intensity and direction
-does not detect an image
2. many-lens compound eyes of insects:
-each unit of the animal has a lens and picks up light from a small portion of the field view
-generates an image from that area only
-all of the lenses together generate the entire picture which is pixelated
3. single-lens eyes of squid:
-similar to a camera
-single lens focuses the image using special muscles in the eye


vertebrate eye

-single lens
-cornea and the flexible lens focus the light (via bending) on the retina which contains photoreceptor cells
-light passes through the lens which bends the light ray such that is falls on the retina
-near sighted individuals are only able to see things that are close
-the object is focused within the eye and not on the retina
-far-sighted individuals are only able to see things that are far away
-the object is focused behind the retina



-locomotion is the active travel from one place to another
-the animal must be able to overcome both gravity and friction
-animals that swim are supported by the body of water but are also slowed by drag created in the water
-animals that move on land are less opposed by friction (air is lighter than water) but they must support their body weight against the force of gravity:
1. hopping
2. running
3. walking
4. crawling


skeletal support

-skeletons provide important structure for movement, protection and support
-muscles pull against the skeleton during movement
-protects internal organs within the cavity
-hydrostatic skeletons:
-fluid held under pressure in a body cavity
-worms and cniadrians
-hard, external cases
-chitinous, jointed exoskeletons of arthropods
-includes shells of some molluscs
-hard or leathery supporting elements within the soft tissue of an animal
-vertebrate endoskeleton is composed entirely of cartilage and bone
-sharks have an endoskeleton composed entirely of cartilage