lecture 18

Question 1

body temperature

Answer 1

• 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

Question 2

heat can be exchanged with the environment in four ways

Answer 2

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

Question 3

conduction

Answer 3

• transfer of heat in between molecules by direct contact

- heat always moves from the hotter object to the colder object

Question 4

convection

Answer 4

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

Question 5

radiation

Answer 5

• emission of electromagnetic waves

- can transfer heat in between objects that are not in direct contact

Question 6

evaporation

Answer 6

• loss of heat from the surface of a liquid

- happens when a molecule obtains enough energy to leave the liquid and become gas

Question 7

adaptation for thermoregulation

Answer 7

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

Question 8

metabolism

Answer 8

• 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

Question 9

insulation

Answer 9

• hair, feathers, or fat

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

Question 10

circulation

Answer 10

• 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

Question 11

evaporative cooling

Answer 11

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

Question 12

behavioral responses

Answer 12

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

Question 13

excretion

Answer 13

• 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

Question 14

reproduction:asexual

Answer 14

• 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

Question 15

reproduction: sexual

Answer 15

• 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

Question 16

reproduction: external fertilization

Answer 16

• 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

Question 17

reproduction: internal fertilization

Answer 17

• 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

Question 18

nervous system: radial symmetry

Answer 18

• 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

Question 19

nervous system: bilateral symmetry

Answer 19

• 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

Question 20

nervous system: vertebrate nervous system

Answer 20

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

Question 21

senses

Answer 21

• 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

Question 22

five categories of sensory receptors

Answer 22

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

Question 23

pain receptors

Answer 23

-detect stimuli that are considered dangerous

Question 24

thermoreceptors

Answer 24

-detect heat or cold, monitors body temp

Question 25

mechanoreceptors

Answer 25

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

Question 26

chemoreceptors

Answer 26

- 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

Question 27

electromagentic receptors

Answer 27

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

Question 28

vision

Answer 28

- 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

Question 29

vertebrate eye

Answer 29

- 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

Question 30

locomotion

Answer 30

- 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

Question 31

skeletal support

Answer 31

- 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 - exoskeleton: - hard, external cases - chitinous, jointed exoskeletons of arthropods - includes shells of some molluscs - endoskeletons: - 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