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BEHAVIOR
Chapter 22.1-22.4
Behavior
An organism’s conduct – the way it acts.
Partly the result of natural selection
Affects the ability of an individual organism to
survive and reproduce.
Successful behavior = live to produce many
offspring.
Studying behavior helps us to understand why
animals, including humans, act the way they do.
Stimulus & Response
Stimulus = anything that triggers a behavior.
External stimuli – stranger approaching
Internal stimuli - thirsty
Response = an organism’s reaction to a stimulus.
Dog barking
Drink water
Innate Behaviors
Innate behavior is influenced by genes, not based on experience.
Taxis (taxes) – change in direction of movement in response to a definite stimulus (planarian).
Always reacts the same way to same stimulus.
Kinesis – a response to stimuli but no particular response
Stimulus can also cause increased/decreased activity
Simple reflex – knee-jerk reflex.
Protects an organism from harm or helps it maintain normal conditions.
Instincts – inherited form of behavior that involves a whole series of reactions that do not require learning or practice.
Nest building in birds (search for good nesting sites, gathering materials, bringing materials to site, making particular type of nest).
Taxis in Planaria
Innate behaviors
Some innate behaviors do not change as a result of
experience.
Fixed-action patterns.
Raccoon washing food
Dog digging to bury bone
Learned Behaviors
Learned behavior develops as a result of
experience.
Imprinting – type of learning that requires little practice
but only occurs during a genetically determined time.
Duckling/goslings
Habituation – exposed to stimulus over and over, it may
lose it’s response or habituate
Train near home while sleeping
Learned Behaviors
Conditioning – one stimulus is associated with another unrelated stimulus.
Pavlov’s dog – bell rings, meat is presented. Bell rings, dog salivates.
Trial-and-error learning- an animal faced with two or more responses learns the one that leads to a reward.
Dog training with treats.
Good or bad tasting food
in nature.
Biological Aspects of Behavior
The nervous & endocrine system control behavior.
Genes affect development of brain.
Most human behaviors are influenced by genes and
environment.
Genetic determination of some behaviors…
Fruit fly foraging widely or close to home.
Honeybees expel diseased bees from hive.
Crickets have distinct chirp patterns.
Environmental & Cultural aspects of
behavior
Environment influences behavior
Choice of clothing
Individual differences
Cultural differences
Symbolic values
External and Internal stimuli influence
behavior
Courting behavior of birds/fish due to hormone levels
which are affected by temperature or time of day.
24.3 Guest Speaker
Noah Heilenbach
Symbiotic Relationships
Friday
24.6 Population Dynamics
Different factors limit the population of each
species
Population density = the # of individuals per unit of
land area or water volume.
Limiting Factors
Factors that limit the productivity of ecosystems
There may be one or several limiting factors in an
ecosystem – limiting factor for the desert is water,
limiting factor for ocean is iron, etc.
Limiting factors can also be biotic – prey can be a
limiting factor
Productivity – conversion of energy and nutrients
into growth
Exponential Growth
If all limiting factors were removed…
Exponential growth of organisms everywhere
Resources will run out and slow growth
Logistic Growth
When the population keeps growing and eventually
becomes stable.
Carrying Capacity – is the largest population of a
species the environment can support
Predator-Prey cycle
Interaction between two organisms of unlike species in which one of them
acts as predator that captures and feeds on the other organism that serves
as the prey. When the number of predators is scarce, the number of prey
should rise and vice versa.
Boom and Bust cycle
When a population exceeds the carrying capacity.
Can result population crash
Reproduction declines
Sharp increase in death rate
CHAPTER 25
Change In Ecosystems
Ecological Succession
Ecosystems are constantly subjected to disturbances
– storm, fire, climate change.
Succession is when one type of community replaces
another.
Two types: Primary and Secondary Succession
Climax Community – Complex relationships now
exist in the community and it has reached a stable
equilibrium (Biomes are climax communities)
Primary Succession
Primary – Begins on bare rock, glacial deposits,
lake beds.
Pioneer species is usually lichen
Secondary Succession
Occurs in a disturbed site where soil is already
present – like an abandoned field, forest fire, etc.
Human Interactions
Common pool resources or Commons – goods and
services provided by ecosystems that can be used
by everyone.
Examples: open ocean fisheries, grasslands, forests,
atmosphere, etc.
Not very regulated, so resources are often
exploited
Human Dominance
Over 7 billion people in the world (6.3 in 2003)
8 billion by 2050? We’ll reach the Earth’s carrying
capacity
Resources will run out, disease sets in, etc. What
else can happen?
http://www.worldometers.info/world-population/
Human Impact
Land use – agriculture, towns and roads, destruction
of natural habitat
Pollution- harming human and animal health, creates
acid rain which prevents forests from growing and
affects aquatic life.
Decrease in Biodiversity – variation of life forms in
an ecosystem
Acid Rain Burning fossil fuels and exhaust from cars adds sulfur
and nitrogen oxides into atmosphere.
The oxides react with water and change into sulfuric
and nitric acids, which fall to Earth as acid rain.
Greenhouse Gases & Global Warming
Greenhouse gases are helpful b/c they trap heat in
our atmosphere. Without them the Earth would be
too cool to sustain life.
Too many greenhouse gases is bad b/c now there is
too much heat increasing our global climate =
Global Warming
Consequences: rise in sea level, damage to coastal
cities
Sustainability We are living in an UNSUSTAINABLE way.
We must use ecosystem goods and services without
ruining or depleting them for future generations…to
be more sustainable!
We need to be more responsible caretakers of our
ecosystems for the future.
CHAPTER 14 & 15
PCR
RFLP’s
Gel electrophoresis – DNA fingerprinting
Recombinant DNA DNA from two different
sources.
Biologist isolate specific
genes and cut them out
using restriction enzymes.
Restriction enzymes cut
DNA at certain sequences.
Cut two different sources
of DNA with same
restriction enzyme to
create complimentary
“sticky ends.”
Restriction enzymes Identify a specific gene of interest and
cut it from the chromosome using
Restriction Enzymes (enzymes that cut
DNA by recognizing and cutting at
specific nucleotide sequences).
If the gene of interest and vector (other
source of DNA) are cut with the same
restriction enzymes then their free ends
can be joined by DNA ligase.
Polymerase Chain Reaction (PCR)
A method of producing
many copies of a
molecule of a DNA
fragment.
These fragments are
called RFLP’s
(restriction length
polymorphisms)
PCR Step by Step
http://www.youtube.com/watch?v=oCRJ4r0RDC4
http://www.you
tube.com/watch
?v=2KoLnIwoZK
U
RFLP Analysis Using restriction enzymes to cut the
DNA of individuals of the same
species at different places results in
DNA fragments of different
lengths.
These RFLP’s can be separated
using Gel Electrophoresis.
Gel electrophoresis separates the
RFLP’s by size.
These patterns function as an
individual "fingerprint," used to
determine whether two DNA
samples are from the same person,
related people, or non-related
people
Gel Electrophoresis Gel electrophoresis refers to using
electricity to move the RFLP’s through a
gel at a certain rate.
Electrophoresis refers to the movement
of a charged particle in an electrical
field.
(+) charged molecules move
towards the negative end of the
chamber.
(-) charged particles move towards
the positive end of the chamber.
DNA is negatively charged
Smaller particles move farther and
faster down the gel b/c they are
lighter.
End result: DNA Fingerprint
The pattern of fragments formed on
the Electrophoresis Gel is known as a
“DNA Fingerprint”
DNA fingerprinting allows scientists
to compare DNA from various
organisms and identify a particular
individual.
DNA fingerprinting can be used in
criminal cases, paternity suits, missing
persons, and unidentified bodies.
Summary
PCR- make many copies of a fragment of DNA
RFLP’s – fragments of DNA (different lengths)
Gel electrophoresis- A method to sort and organize
the RFLP’s or DNA fragments by size to create a
DNA fingerprint.