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Animal Form & Function
Chapter 40

Levels of organization
– Tissues (group of cells with common structure
& function)
– Organs (functional units of tissues)
– Organ systems (organs that work together)

4 main types of tissue:
– 1) Epithelial
 Sheets of tightly packed cells, covers the body,
lines organs, and protects
 One side is always bound to a basement
membrane
 Other side faces air or fluid environment
– 2) Connective
 Supports and binds
 Cartilage, tendons, ligaments, bone, & blood

3) Muscle
– Body movement
– Muscle filaments are made of actin & myosin
(proteins)
– The fibers contract when stimulated by a nerve
– Most abundant tissue in animals
– 3 types:
 Skeletal – used for movement & is voluntary
 Smooth – found in organs & is involuntary
 Cardiac – in heart & is involuntary

4) Nervous
– Functional unit is a nerve cell (neuron)
– Senses stimuli & transmits signals from one
part of the body to another

2 major systems that coordinate and control the
tissue, organ, and organ systems of animals:
– 1) Endocrine
 Hormones are chemical messengers
 Carried in the blood to all parts of the body
 Hormones have specific functions, but only with cells with
specific receptors
 Come from glands (pituitary, thyroid, etc.)
– 2) Nervous
 Transmit information between locations
 3 types of cells receive nerve impulses: neurons, muscle
cells, & endocrine cells
Homeostasis – constant internal
environment
 The body has a “set point” (i.e. body
temp), sensors to detect any variation in
the set pt, & physiological responses to
help return to the set pt


Physiological responses:
– 1) Negative feedback loop
 Respond to stimulus in a way that reduces the
stimulus
 Ex: in response to exercise, the body temp rises,
which initiates sweating
– 2) Positive feedback loop
 A variable triggers mechanisms that amplify rather
than reverse the change
 Ex: childbirth – stimulates uterine contractions

Thermoregulation = how animals maintain
their internal temperature
– Endotherms (mammals/birds) use heat
generated by metabolism (warm blooded)
– Ectotherms (invertebrates, fish, reptiles) use
heat from external sources (cold blooded)
Chapter 41

4 classes of essential nutrients:
– 1) Essential amino acids
 12 of 20
– 2) Essential fatty acids
– 3) Vitamins
– 4) Minerals

4 main stages of food processing:
– 1) Ingestion
 Taking in food
– 2) Digestion
 Breaking down food
– 3) Absorption
 Cells take up small molecules
– 4) Elimination
 Passing of undigested material

Simple animals utilize a gastrovascular
canal
– Single opening for food and wastes
– Worms & hydras use this

Complex animals use alimentary canals
– One-way digestive tubes that have 2 openings

Movement of food through the DS is
controlled by peristalsis
– Waves of contractions by smooth muscle

Food is taken into the mouth
– Releases saliva
 Aids in swallowing
 Begins chemical digestion
 Contains amylase (breaks down starch & glycogen)
The chewed food forms a BOLUS
 The bolus then enters the pharynx
(throat)
 During swallowing, the EPIGLOTTIS
covers the trachea so food goes down the
ESOPHAGUS
 Esophagus moves food to the stomach
through peristalsis


Stomach – stores food and secretes
gastric juices:
– 1) Hydrochloric acid
 pH of 2
 Breaks down meat and plants
 Kills most bacteria
– 2) Pepsin
 Hydrolyzes proteins
End result of the stomach work is acid
chyme which is moved to the small
intestine
 Duodenum – major site of chemical
digestion (1st section of SI)

– Works with pancreas & liver
– Pancreas produces a buffer
– Liver produces bile (fat breakdown)
Chemical breakdown in duodenum:
 1) Carbs

– amylases

2) Proteins
– Pepsin/trypsin

3) Nucleic Acids
– Hydrolysis of DNA/RNA

4) Fats
– Bile/lipase
Chapter 48

Nerve cell = neuron
– Composed of:
 Cell body – contains nucleus & organelles
 Dendrites – cell extensions that receive incoming
messages
 Axons – transmit messages
– Many axons are covered by a fatty myelin sheath
– Speeds rate of transmission
Synapse = junction between neurons
 Neurotransmitters are chemical
messengers that bind to receptors
 Sensory receptors

– Collect information about the world outside
the body as well as inside (ex: rods/cones of
eyes & pressure receptors in the skin)

Sensory neurons
– Transmit information from sensors to the
brain/spinal cord

Interneurons
– Connect sensory & motor neurons
Chapter 49

Evolution of nervous system
– Cnidarians have a nerve net
– Cephalization clusters sensory neurons &
interneurons
– Flatworms have a small brain & longitudinal
nerve cord (simplest Central Nervous System)
– Annelids (earthworm) & arthropods have a
ventral nerve cord
– Vertebrates have a hollow dorsal nerve cord

Reflex
– Simple automatic nerve circuit in response to
a stimulus
– Ex: The stimulus is detected by a receptor in
the skin, conveyed via a sensory neuron to an
interneuron in the spinal cord, which synapses
with a motor neuron, which will cause the
effector, a muscle cell, to contract
Conscious thought is not required in a
reflex
 Cerebrospinal fluid (CSF) circulates
through a central canal in the spinal cord
& ventricles of the brain – cushions the
brain & spinal cord

Gilia – support neurons
– Astrocytes (support neurons)
– Oligodendrocytes (form myelin sheaths in CNS)
– Schwann cells (form sheaths in PNS)
 Gray matter
– Mainly neuron cell bodies & unmyelinated axons
 White matter
– White due to the myelin sheaths

Nervous System
Central Nervous
System (CNS)
Brain
Spinal Cord –
nerve bundle
Peripheral
Nervous System
(PNS)
Autonomic NS Involuntary
Somatic NS –
voluntary
Parasympathetic
– rest & digest
Sympathetic –
fight or flight
Main Brain Anatomy

1) Brainstem
– Medulla oblongata, pons, midbrain
– Controls homeostatic functions – breathing
rate
– Conducts sensory & motor signals between
the spinal cord and higher brain centers
– Regulates arousal and sleep

2) Cerebellum
– Coordinates motor, perceptual, & cognitive
functions
– Balance

3) Cerebrum
– Largest part of the brain
– Has left/right hemispheres
– Covering of gray matter over white matter
– Information processing
– Thinking, learning, remembering
Other brain parts




Thalamus
– Main center through which sensory & motor
information passes to & from the cerebrum
Hypothalamus
– Regulates homeostasis
– Feeding, fighting, fleeing, reproducing, circadian
rhythms
Cerebral cortex
– controls voluntary movement & cognitive functions
Corpus callosum
– Enables communication between left/right
hemispheres
Chapter 51

Behavior
– What an animal does and how it does it
– Result of genetics & environment
– Essential for survival & reproduction
– Subject to natural selection

Ethology
– Study of animal behavior
2 levels of analysis in the study of
behavior:
 1) Proximate

– The “how” questions & include effects of
heredity, genetic-environmental interactions,
& sensory-motor mechanisms

2) Ultimate
– The “why” questions & studies of origin of
behavior, change over time, & reproductive
success


Innate behavior
– Developmentally fixed – unlearned
– Nursing in mammals
Fixed action pattern (FAP)
– Sequence of unlearned acts that is largely
unchangeable & carried to completion when started
– Triggered by sign stimuli
– EX: male stickle-back fish which attack red objects –
the red object is the sign stimulus, attack is FAP



Kinesis
– Simple change in activity in response to stimulus
– Ex: pillbugs to moisture
Taxis
– Automatic movement toward or away from a stimulus
– Ex: moths to light
Migration
– Complex
– Attributed to detection of Earth’s magnetic field or visual cues

Circadian rhythms
– Occur daily

Signal
– A behavior that causes a change in the behavior of
another – basis for animal communication
– 1) Pheromones – chemical signals
– 2) Visual Signals – warning flashes, markings
– 3) Auditory Signals – sounds, screeches, growls
– 4) Waggle dance – done by honeybees
 http://www.youtube.com/watch?v=-7ijI-g4jHg
51.2

Learning
– Modification of behavior based on experiences

Imprinting
– Combination of learned & innate components
that are limited to a sensitive period in an
organisms life and is generally irreversible
– Konrad Lorenz
 http://www.youtube.com/watch?v=2UIU9XHmUI&feature=related

Habituation
– Loss of responsiveness to stimuli
– Simple form of learning

Cognitive map
– Internal representation of spatial relationship
among objects in an animal’s surroundings

Associative learning:
– Ability of many animals to associate one
feature of their environment with another
feature
– Two types:

1) Classical Conditioning
– Learning to associate certain stimuli with
reward or punishment
– Pavlov

2) Operant conditioning
– Occurs as an animal learns to associate one of
its behaviors with a reward or punishment
– B.F. Skinner
Skinner Box
51.3

Both environment and genetics contribute
to behavior
51.4

Survival and reproductive success
– Foraging behavior
 Not only eating, but mechanisms used in searching
for, recognizing, & capturing food
– Optimal foraging model
 A compromise between benefits of nutrition & cost
of obtaining food

Mating systems – varies
– 1) Promiscuous – no strong pair-bonds
– 2) Monogamous – one male/one female
– 3) Polygamous – one individual mating with
others
51.5


Altruism
– When animals behave in ways that reduce their
individual fitness but increases the fitness of other
individuals in the population
– Ex: blue jay giving an alarm call
Inclusive fitness
– Total effect an individual has on proliferating its
genes by producing its own offspring
– Provides aid that enables other close relatives to
produce offspring
– “kin selection”