Exam I Flashcards
Ethology
the scientific study of animal behavior, especially in the natural context
Tibergen
father of modern ethology
Tibergen’s four questions
approach the study of behavior by asking four questions
- Function - how does the animal’s behavior impact its chances of survival and reproduction
- Causation - what are the stimuli that elicit the behavior and how have the physiological models been modified by experience
- Development - how does the behavior change with age and what are the critical periods?
- Evolutionary History - how does the behavior compare with similar behaviors in related species? how might this behavior have arisen through evolution
John Baptiste Lamark
studied fossils, plants, invertebrates
concluded: transmutation of species (species change over time)
Principles:
( 1 ) Use and disuse (used organs grow stronger, disused ones grow weaker)
( 2 ) inheritance of acquired traits (offspring display traits acquired by parents during lifetime)
Charles Darwin
father of modern biology
Theory of Natural Selection
first described a biological mechanism to explain speciation and the adaption of traits
first to use a comparative phylogenetic method to study behavior
Alfred Wallace - similar ideas
Gregor Mendel
physical traits passed from parent to offspring through genes
Thomas Hunt Morgan
studied flies, found that genes were located on chromosomes
von Frisch
FOCUS: COOPERATIVE BEHAVIOR AND GROUP LIVING
honey bees dance to communicate foraging site distance/direction
Tinbergen
BEHAVIOR IN THE NATURAL WORLD
instinct and learning
sign stimuli: stimulus releases action pattern; input activates a motor program
ex: sticklebacks attack anything red during mating season (color red released attack response)
ex: red herring
Lorenz
INSTINCTIVE BEHAVIOR AND FIXED SEQUENCES
instinctive behavior, fixed sequences
imprinting and critical periods
Lorenz found that geese follow the first moving object they see, during a 12-17 hour critical period after hatching.
imprinting: suggests that attachment is innate and programmed genetically
critical period: within 32 hours, it’s unlikely any attachment will ever develop
in order to understand the mechanisms of animal behavior, it was necessary to observe their full range of behaviors in their natural context
Herring gull
red spot on parent’s bill –> chick hatches –> parents feed on fish –> chick pecks red spot –> parent regurgitates food
Stickleback fish
attack anything red during mating season (color red released attack response)
used when other male sticklebacks that were competing for nesting territory
many false alarms but also relatively few failures to drive off competing male sticklebacks
Stickleback fish
sign stimulus: red
attack anything red during mating season (color red released attack response)
used when other male sticklebacks that were competing for nesting territory
many false alarms but also relatively few failures to drive off competing male sticklebacks
Tinbergin’s 4 questions, red herring
chick pecks on red bill
- Function
allows chick to get fed –> chick can survive and grow, eventually produce its own young - Causation
eyes detect yellow bill with red spot –> visual system perceives signal, motor system sends commands to muscles –> muscles move chick to peck red spot
WHAT ASPECTS TRIGGER RESPONSE? beak shape, spot orientation, color, etc.
head shape, size and color do not matter
cues: (1) color of spot, (2) contrast between spot and bill
- Development
chick performs behavior shortly after hatching, does it before seeing it –> innate - Evolutionary History
laughing gull: chick opens bill and closes it around parent, parent regurgitates to baby
shared trait suggest behavior was present in a common ancestor but red spot evolved after species diverged
Additional lesson from birds
Chick changes behavior after experiencing parent’s response, Behavior can be modified by experience
Example of a behavior resulting from the combination of an instinct to stimulate parent’s bill and learning how to elicit the feeding
sign stimulus
sensory cue that triggers the behavior
(red spot on bill)
ex: Red herring
Sign stimulus for chick = red spot on bright billSign stimulus for parent gull = chick’s pecking on bill
social releaser
sign stimulus that is emitted and received by the members of the same species
super-normal stimulus
an exaggerated sign stimulus
(GIANT red spot on bright bill)
ex: Oystercatchers were willing to roll huge eggs into their nests to incubate
ex:
Black oystercatchers
respond more strongly to super-normal stimuli
Oystercatchers were willing to roll huge eggs into their nests to incubate
Cuckoo Chick
Cuckoo chick and reed warbler
Parasitic cuckoo chick is preferentially fed by host parent because it is larger, begs more and more loudly for food that the host species chicks
Fixed action pattern (FAP)
(FAP) a stereotyped motor response that may be initiated by an environmental stimulus
Chick’s FAP = pecking parent’s bill
Parent’s FAP = regurgitating fish
Sign stimulus –> FAP
Sign stimulus: red spot on bill
FAP: peck
Sign stimulus: peck
FAP: regurgitate fish
Greylag goose
if an egg becomes displaced from the nest, the greylag rolls it back to the nest with its beak
sight of missing egg = sign stimulus
elicits FAP: egg retrieval
Greylag goose
DEMONSTRATES FIXED ACTION PATTERN
if an egg becomes displaced from the nest, the greylag rolls it back to the nest with its beak
sight of missing egg = sign stimulus
elicits FAP: egg retrieval
If the egg is removed from the goose during the performance of egg-rolling, the bird often continues with the behavior, pulling its head back as if an imaginary egg is still being maneuvered by the underside of its beak.[4] The greylag will also attempt to retrieve other egg-shaped objects, such as a golf ball, door knob, or even a model egg too large to have possibly been laid by the goose itself
Chain of reactions
sequences of sign stimuli and FAPs between individuals
ex: mating rituals
ex: stickleback fish
male sees female (ss)
performs zig-zag dance (fap)
female watches male dance (ss)
female displays swollen belly (fap)
male sees swollen belly (ss)
male leads female to nest and prods her into lay egging station (fap) –> female lays eggs
Homology
the evolution of traits that differ but still have similar basic structure due to common ancestral origin
ex: vertebrate limb
Analogy
evolution of similar traits due to similar environmental pressures rather than common ancestor
ex: flying mammals – sugar gliders and flying squirrels
(Natural selection independently adapted both lineages for similar lifestyles: leaping from treetops (hence, the gliding “wings”) and foraging at night (hence, the big eyes)
ex: eye organization (vertebrate and cephaloid)
Scientific Method
- Observe and describe (qualitative stage, what and why)
- Hypothesis (forming an educated guess)
- Prediction (IF…THEN)
- Test Experiment (quantitative stage)
- Drawing conclusions
Scientific Method (A/B)
- OBSERVE Variables A and B are changing
- HYPOTHESIZE Changes in variable A are resulting in changes in variable B
- PREDICT If A increases, then B will increase
- TEST Measure B, increase A, measure B again
- Drawing conclusions
Independent, Dependent Variables
Independent: what you manipulate
Dependent variable: change caused, dependent on independent variable
If I add fertilizer to plant W and none to V, then W will grow faster.
fertilizer: independent variable
growth rate: dependent variable
Null hypothesis
no effect of manipulation
Drawing conclusions based on
magnitude of difference
variability of values
sample size
p-value
Statistical tests of differences between groups give a P-value
P value: likelihood that the observed difference is due to chance
convention = P<0.05
After conclusions drawn
Repeat and continue getting same results
Repeated by different scientists
Establish a consensus that is widely accepted
Theory
a scheme that offers a broad, fundamental explanation of many observations
based on all tested hypotheses
deals with HOW or WHY something happened, not just an idea
Law
empirical statement that summarizes known relationships
states THAT something happened
Francis Bacon
inductive reasoning
- Begin with observations of nature
- Goal is to find true statements about how nature works
- If nature conflicts with the idea, then the idea must be changed or abandoned
Science is a process
theories are based on consensus built among scientists
continuous refinement of understanding rather than definitive proof
don’t assume absolute knowledge, there will always be uncertainty
2 types of experiments
- Planned experiment
- IV manipulated by scientist, DV is measured - Natural experiment
- IV occurs naturally, DV measured
Tephritid experiment
fly mimicking spider
Wing markings and wave display likely mimic jumping spider displays and reduce predation by jumping spiders
Finches (natural)
drought
- Drought resulted in many large, hard seeds, few small soft seeds
- Smaller beaks cannot crack large seeds
- Birds with deeper beaks more likely to survive and reproduce
- Deeper beaks become more common in the populatio
Effect on beak depth in offspring of surviving medium ground finch
Mean beak size eventually returned to original
–> Natural selection favors beak characteristics that allow exploitation of available food type
Kroodsma paper
psuedoreplication
using inferential statistics to test treatment effects with data from experiments where treatments are not replicated or replicates are not statistically independent
If we test the difference in birds’ responses to song A and song B, can we generalize the results to all songs from category A and category B?
Evidence for natural selection
- Domesticated animals change through natural selection
- species change over time, many descendants from single ancestor are possible, selection leads to evolution
- Existence of fossils
- show organisms similar but not same as previous species
- Species change through time
- extinction
- law of succession: fossil species in a given area are replaced by a similar living species
- transitional forms: some fossils show intermediate characteristics between living taxa
- vestigial structures: - Molecular homology
- closely related animals contain similar DNA sequences
- By analyzing the protein structure of complex molecules, relatedness of animals can be estimated
Similarities for natural/artificial selection
Differences for it
variation in populations
some of the variation is heritable
different variants produce different numbers of offspring
difference: agents of selection
Law of succession
fossil species in a given area are replaced by a similar living species
Transitional forms
some fossils show intermediate characteristics between living taxa
Archaeopteryx (150 mya)
Reptile-like traits: claws, sharp teeth, long tail
Bird-like traits: feathers, wings, big toe
Vestigial structures
structures/organs that appear to have no function but do have a function in closely related organisms - function can change faster than structure
goosebumps
pelvis in whale
Bar headed goose
Migrates over Mt. Everest
Increased oxygen affinity in blood
PHILOGENETIC TREE
Before Darwin
Theory of “Great Chain of Being” - God created infinite and continuous series of life forms
- created independently
- do not change over time
- created recently, at virtually the same time
- mechanism: created by supernatural force
Carolus Linnaeus
First to organize species into a taxonomy
Created the system of binomial nomenclature for naming organisms (genus, species)
but still believed in Special Creation
Taxonomy
a classification of living things, usually hierarchical
Lamarck
CONCEPT OF EVOLUTION
theory of use and disuse
evolution occurs by phenotypic adaptation and passing that adaptation on to offspring
the inheritance of acquired traits
giraffe example
Theory of common descent
Allspecies descended from one or a few original species = ‘Descent with modification’
through natural selection
4 postulates for the logic of Darwin’s theory
- variation exists
- heritability
- struggle for survival (reproductive potential and survival rates)
- Survival and reproduction are not random (favorable traits persist – AKA natural selection!)
Adaptive trait
increases the ability of an individual to survive and reproduce relative to individuals without that trait
Lifetime Reproductive Success
heritable traits that lead to the production of the most offspring will become more common over time
What is natural selection contingent upon
Natural selection will lead to evolutionary change only if the phenotypic differences are due to genotypic differences
Genotype v. phenotype
Phenotype: physical and behavioral traits
Genotype:“blueprint” - genetic instructions present in an organism
Natural selection v. evolution
Natural Selection acts on individuals
Evolution occurs in populations
Darwin’s success was related to
Studying the literature
Independence of thought/don’t just believe it
Patience and focus - time spent observing and carefully documenting - attention to detail
Recognizing the inter-relatedness of behavior, environment and social interaction
Ingenious tools/methods
Homologous traits
traits that are similar to one another due to shared ancestry
ex: common structure of the vertebrate limb
divergent evolution from same origin
Analogous
not related, similar traits due to similar environmental pressures
ex: sugar glider and flying squirrel
ex: vertebrate eye and cephlapod eye
convergent evolution from different origins
Behavior causes
ultimate cause: why a behavior exists
(1.function, 4.evolutionary history)
proximate cause: how a behavior is implemented and controlled
(2.causation, 3.development)
Singing behavior
combination of innate and learned traits
Why do birds sing
attract females
compete with males
- Remove birds from territory. Play song / measure # territory invasions
reproductive success
Song learning
sing to baby, learns it
female listens to know what to look for
Juveniles preferentially learn conspecific song
But will learn another species’ song
Brain of songbird
HVC is the higher vocal center. It is a bird’s brain center for learning and production of song
LMAN is the lateral magnocellular nucleus that is involved in learning new sounds or words.
RA is the robust nucleus, somewhat similar to the human cortex.
Area X in the bird’s striatum. The striatum is the center of motor learning, also called habit learning. This is region with the most genes.
Sex differences in songbird brain
RA bias toward males (bigger)
3 clades of songbirds
parrots
hummingbird
songbird
nature v. nurture
behaviors develop guided by genetic predispositions and experience
How a behavior evolved is reconstructed using
trait similarities mechanism similarities (sensory structures, brain, muscles) phylogenetic relationships (relatedness)
Brain systems song birds
!!!
Evolutionary history, relatedness of songbirds
!!!
vocal learning may have evolved 3 times
Or, evolved once in a common ancestor, then was lost in 6 times
Or, evolved once in a common ancestor, then was lost in 8 timesOr, evolved 2 times and was lost once
Developmental switch mechanism
fish
Stages of behavior
bee
MORE
Each caste has separate jobs
Determination of type depends on genotype and chemical signal
worker: f, raises pupae, maintains/builds hive, forages/collects food, regulate hive temp, makes the honey, guards the hive
drone: impregnates female, dies
queen: breeds, lays eggs, emits pheromones
Developmental switch mechanism
Physiological mechanisms that cause the development of alternative phenotypes in response to environmental cues
polyphenism
Polyphenism – ability of a genome to develop dramatically different phenotypes
Classical conditioning
training a response to a neutral stimulus by associating the neutral stimulus with the meaningful stimulus
Based on involuntary behavior
US, UR, CS, CR
US – food
UR - salivate
CS – sound
CR - salivate
Operant conditioning principles
Operant Conditioning – training/shaping behavior by means of reinforcement and punishment
positive, negative
reinforcement, punishment
Based on voluntary behavior
- Behavior that is positively reinforced will recur; intermittent reinforcement is particularly effective.
- Information should be presented in small amounts so that responses can be reinforced (shaping).
- Reinforcements will generalize across similar stimuli (stimulus generalization) producing secondary conditioning
Bright Noisy Water experiment
Pairing sweet water with nausea results in learning to avoid water
Pairing bright light or loud noise with shock results in avoidance learning
Pairing sweet waterwith shock DOES NOTresult in avoidance
Pairing sound with nausea DOES NOT result in avoidance
WHY? Learning depends on the life history and therefore the physiology of the species
derived trait
Derived Trait: arisen relatively recently - define evolutionary relationships better than ancestral traits because they are not shared by all taxa
e.g. feathers on legs
ancestral trait
Ancestral Trait: present for a long time and is shared by many species - limited in helping map phylogeny of related species
e.g. wings on birds
Adaptive radiation
the diversification of a group of organisms into forms filling different ecological niches.
- one ancestor
- diverge in different environements
- sympatric when they exist in the same geographic area and thus frequently encounter one another
Speciation
the formation of new and distinct species in the course of evolution
spectrogram, oscillogram
Spectrogram: time and pitch (frequency)
Oscilligram — amplitiude (volume) and time
Parts of scientific paper
AIM RD
Abstract - summary and key questions
Intro - literature review
Methods - experimental design and techniques
Results - quantitative report on findings
Discussion
Bacon’s basic tenants
inductive reasoning
Basic tenets:
- Begin with observations of nature
- The goal is to find statements that are true about how nature works (theories or laws).
- If nature conflicts with the idea, then the idea must be changed or abandoned.
Innate releasing mechanism
Fixed action patterns, or similar behaviour sequences, are produced by a neural network known as the innate releasing mechanism in response to an external sensory stimulus known as a sign stimulus or releaser.
Null hypothesis
no relationship between two measured phenomena
hypthothesis
HYPOTHESIZE Changes in variable A are resulting in changes in variable B
forming an educated guess
Special creation
the universe and all life in it originated in its present form by unconditional fiat or divine decree
taxonomy
the branch of science concerned with classification, especially of organisms; systematic
Linnaeus
heritability
the proportion of phenotypic variance attributable to genetic variance
Extinct
no longer living
Extant
living, still in existence
Transitional forms
any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group
Phylogeny
the study of the evolutionary history and relationships among individuals or groups of organisms
cladogram
Draw
Archeopteryx
example of transitional form
Archaeopteryx (150 mya)
Reptile-like traits: claws, sharp teeth, long tail
Bird-like traits: feathers, wings, big toe
Basilosaurus
initially believed to be some sort of reptile, hence the suffix -saurus, but it was later found to be a marine mammal
hind limbs
Molecular homology
comparison of amino acid sequence to show relationship relatedness
mutation
change in an organism’s DNA
gene flow
migration/gene flow,
Polyphenisms
multiple, discrete phenotypes can arise from a single genotype as a result of differing environmental conditions. It is therefore a special case of phenotypic plasticity.
A series of polyphenisms determines whether larvae develop into queens, workers, or drones
Parallel evolution
similar environmental pressure, two species develop in similar ways
types of evolution
convergent
divergent
parallel
cladogram
Sister taxa
Node
Branch
Root
Philip Gingerich
whale evolution
Wales and dolphins = mammals who live in the water
Back of skull, ear region of whale
Similar to wolf skull
Claim: whales evolved from land mammals
Transitional forms
Basilasourus had pelvis, knee cap, toes — complete set of leg bones
Whales had once been 4-legged animals
Scinonxyx
Walcott
found a wealth of Cambrian fossils in the Rocky Mountains
Gardner
?
Adaption
reproductively advantageous
