Transcript Animal behaviour - McGraw Hill Higher Education

Chapter 30: Animal behaviour
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-1
Ethology
• Ethology is the study of animal behaviour
• It documents behaviour and examines the causes
and outcomes of observed behaviour
• Studies investigate
–
–
–
–
causation
development
adaptive value
evolutionary history
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-2
Genetics and the evolution of
behaviour
• Because behaviour is part of an animal’s
phenotype, it is subject to natural selection and
sexual selection
• Selection acts where there is variation in behaviour
between individuals in a population
• Animal behaviour is often a balance between
several alternative behaviours
– hide from predators and starve; or
– forage and run the risk of being eaten?
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-3
Fig. 30.1: Bowerbirds
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-4
Genetic markers
• Behaviour has a genetic basis
– mutations in genes may alter behaviour
• Studies of fruit flies (Drosophila melanogaster)
have identified some behaviours under genetic
control
– duration of copulation is affected by mutations in muscles
and sensory receptors
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-5
Selection experiments
• Artificial selection is used to develop preferred
traits in domesticated animals and plants
– coat pattern in cats, grain yield in wheat
• It can also be used to select behaviours in animals
– behaviour of courting male Gryllus crickets varies—some
sing, others are silent
– selective breeding from singing males increases
frequency of singing in subsequent generations
– singing has a genetic basis
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-6
Populations with genetic differences
• Populations may exhibit differences in behaviour
• Garter snakes (Thamnophis elegans) in southwestern United States live in coastal and inland
regions
– coastal snakes are terrestrial slug-feeders
– inland snakes are aquatic frog-feeders
• Feeding experiments demonstrated that food
preference is inherited
– preference results from selection for local conditions
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-7
Learning and the development of
behaviour
• Learning is a long-term or permanent change in
behaviour due to experience
• Maturational effects (change in behaviour during
development) are not the result of experience so
they cannot be classified as learning
• Imprinting is both a learned behaviour and a
maturational effect
– goslings and other chicks will follow the first moving
object they see
– imprinting occurs only within a restricted sensitive period
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-8
Fig. 30.2: Imprinting
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-9
Learning and the development of
behaviour (cont.)
• Galah (Cacatua roseicapilla) chicks raised by pink
cockatoos (C. leadbeateri) show learned behaviour
– Fostered galah chicks give typical galah alarm and
begging calls (inherited behaviour)
– But they give pink cockatoo contact calls (learned
behaviour)
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-10
Learning and the development of
behaviour (cont.)
• Learning can be associative or non-associative
• Associative
– learning in response to a stimulus
– trial-and-error
• Non-associative
– learning without a stimulus
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-11
Evolutionary basis of behaviour
• Methods for examining the evolutionary basis of
behaviour
• Intraspecific comparisons
– comparing behaviour of individuals within a species
• Manipulative experiments
– focused experimental studies of selected behaviour
• Interspecific comparisons
– comparing behaviour of individuals in different species
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-12
Question 1:
Which of the following is not required for a
behaviour to evolve?
a) The behaviour varies amongst individuals
b) Some component of the behaviour is genetically
inherited
c) In every individual the behaviour is determined
solely by its genes
d) An individual’s genotype influences its phenotype
e) An individual’s reproductive success depends in
part on how the behaviour is performed
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-13
Obtaining food
• Animals exhibit a range of diets
– have a wide variety of strategies to obtain food
– predators may actively forage for prey or sit and wait
(ambush it)
• Foraging is not random
– individuals make decisions that represent the best
balance between cost (energy expended in foraging) and
benefit (energy gained from food)
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-14
Fig 30.5: Examples of the ways
animals obtain food
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-15
Foraging theory
• Foraging theory evaluates costs and benefits and
predicts the decision under different conditions
• Other factors may influence the calculation of cost
and benefit
– risk of predation
– intraspecific competition
– interspecific competition
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-16
Avoiding being eaten
• Defence mechanisms minimise the risk of
predation
– fast-moving animals may outrun predators
– animals may produce noxious chemicals to deter
predators
– camouflaged animals may be overlooked by predators
– animals may mimic unrelated species
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-17
Mimicry
• Animals may mimic other organisms by visual,
chemical, behavioural or acoustic resemblance
• Prey animals use defensive mimicry to decrease
the chance of predation
– harmless species resemble unpalatable or dangerous
species to avoid being eaten by predators
• Predators use aggressive mimicry to increase
the chance of catching prey
– example: bolas spiders (Dichrostichus) produce a
substance that resembles the mate-attracting
pheromones of moths
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-18
Fig. 30.6: Juvenile long-horn
grasshoppers
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-19
Living in groups
• Living in groups reduces the chance of predation
– probability of any individual being caught decreases as
the size of the group increases
– probability changes with location within the group as
those on the edge have a greater chance of being eaten
than those in the centre
– flocking behaviour may produce a confusion effect and
distract predators from singling out individuals
– groups of animals may harass (mob) predators and drive
them off
– groups can detect predators with greater success than a
single animal can
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-20
Competition and territorial behaviour
• When resources are limited, individuals may
compete for them
• Establishing a territory excludes competitors from
resources in that area
– territory-holders benefit by having exclusive access to the
resources
– but they pay a cost in defending the territory
• Individuals, pairs or groups may hold territories
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-21
Animal contests
• Competition for resources frequently involves
contests (direct conflicts) between individuals
– as both individuals in a contest may suffer injuries in a
physical confrontation, contests are usually settled before
injury occurs
– winners benefit by gaining access to the resource but pay
a cost in energy expended (or injury)
• Outcome of contests depends on
– ability of contestants
– value of resource to each contestant
– which contestant owns resource
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-22
Fig. 30.11: Contest between male red
kangaroos
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-23
Finding a mate
• Animals use many methods for locating a mate
• Chemical signals
– female moths release pheromones to attract males,
which may detect the signal from a distance of several
kilometres
• Auditory signals
– male frogs call to attract females
• Visual signals
– male fireflies produce flashes of light to attract females
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-24
Courtship
• After locating each other, potential mates display
courtship behaviour
• Courtship behaviour
– confirms that the potential mates belong to the same
species
– confirms that the individuals are ready to mate
– may provide some indication of the fitness of the
signalling mate
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-25
Sexual selection
• Elaborate displays and ornaments used in
courtship are the product of sexual selection
– sexual selection acts on the characteristics that influence
a male’s chance of fertilising a female’s eggs
• Male–male competition
– intrasexual selection in which males compete with each
other for females
• Female choice
– intersexual selection in which females choose their mates
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-26
Fig. B30.3a: Peacock
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-27
Courtship (cont.)
• Gift-giving occurs among some species
– male lygaeid bugs provide the female with a nuptial gift
containing nutrients that increase the size or number of
her eggs
• Courtship behaviour reduces the likelihood of
sexual cannibalism
– eating the male may provide nutrients for egg-production
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-28
Fig. 30.14: Lygaeid bug
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-29
Sperm competition
• If a female mates with more than one male, there
may be competition between sperm to fertilise her
eggs
• Males reduce the risk of sperm competition by
– guarding a female to prevent other males mating with her
– producing chemicals in ejaculates that make females
unreceptive after mating
– sealing the female genitalia after mating
– dislodging sperm from previous matings
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-30
Parental care
• In those species that provide parental care, one or
both parents may be involved in taking care of the
offspring
• As with many behaviours, the amount of care
depends on the balance between
– benefit of increased survival rate of young
– cost of lost opportunities for mating
• Difference in behaviour
– females commonly invest greater effort in rearing
offspring than males
– males may spend time seeking extra-pair copulations
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-31
Mating systems
• An individual may mate with one or more partners
during a mating season
• Mating systems are divided into four categories
– monogamy
 one male mates with one female
– polygyny
 one male mates with several females
– polyandry
 one female mates with several males
– promiscuity
 males and females mate with several partners
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-32
Social organisation and co-operative
behaviour
• Permanent groups exhibit social behaviour
– individuals in a group cooperate to
 find food
 defend the group
 rear young
• Many groups have complex social structures
depending on the interests and needs of the
individuals
• Conflict is avoided in some groups by establishing
dominance hierarchies
– pecking orders
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-33
Fig. 30.20: Castes of the myrmicine
ant
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-34
Cooperative breeding
• Cooperative breeders share the task of rearing
young between members of a group
• Depending on the species, family members and/or
unrelated helpers assist parents to raise offspring
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-35
Insect societies
• Hymenopteran insects (bees, ants, wasps) and
termites form complex eusocial societies
• Eusocial societies are characterised by
– overlapping generations
– reproductive division of labour
• Colonies are composed of
– reproductive queen
– sterile female workers in one or more specialised castes
– reproductive males
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-36
Insect societies (cont.)
• The queen is the only female that produces
offspring
– fertilised eggs give rise to workers
– unfertilised eggs give rise to males
• When the colony reaches a certain size, the queen
produces reproductive females, which leave the
nest
• Castes in eusocial insects are often highly
specialised
– among honey-pot ants (Camponotus), some individuals
act as sedentary food stores for others in the colony
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-37
Evolution of cooperation
• Altruistic behaviour tends to reduce the
reproductive success of an individual, so why does
it persist in some species?
– most ‘altruistic’ behaviour has a hidden benefit
• Explanations of cooperation in eusocial behaviour
– helping is of mutual benefit to parents and workers
– workers are manipulated into helping parents
– cooperation between individuals that are closely related
evolves because they share a higher proportion of genes,
so sisters may share more genes than mother and
daughter
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-38
Question 2:
Which of the following is true?
a) Natural selection does not favour altruistic
behaviour that causes the death of the altruist
b) Altruism is always reciprocal
c) Natural selection is more likely to favour altruistic
behaviour that benefits offspring than altruistic
behaviour that benefits a sibling
d) Natural selection should favour altruistic acts when
the resulting benefit exceeds the cost to the altruist
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-39
Summary
• Behaviour has a genetic basis and therefore can
be subject to the influence of natural selection
• Behavioural choices generally reflect trade-offs
between costs and benefits
• Conflict over resources can result in contests
between members of the same species
• Courtship behaviour can be auditory, chemical or
visual in nature and often allows for a female to
choose a partner based on behaviour
• Parental care increases the chances of offspring
survival
Copyright  2010 McGraw-Hill Australia Pty Ltd
PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint
Slides prepared by Karen Burke da Silva, Flinders University
30-40