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43.4 Behaviors That Increase Fitness
For each type of communication, identify the human receptor.
There are various strategies that increase an individual's fitness.
According to investigators, certain behaviors lead to increased survival and production of offspring.
The adaptive value of the behavior we can observe in a species is still present.
In order to gather food, many animals have a home range.
An animal's territory may have a good food source, and the area in which the animal will reproduce.
gibbons live in the tropical rain forest of South and Southeast Asia.
They can travel their home range in about 3-4 days.
Gibbons are territorial and monogamous.
Territories are maintained by loud singing.
Men sing just before sunrise and women sing duets in the morning.
Males show evidence of fighting to defend their territory in the form of broken teeth and scars.
It takes energy to sing and fight off other people.
They both have the same task of marking their territory by singing.
In monogamous relationships, the sexes are similar in appearance.
The male and female are above each other.
Territoriality must have an adaptive value in order to continue.
Territoriality provides access to a source of food, breeding opportunities and a place to rear young.
Too large a territory can't be defended, and too small a territory can't contain enough resources.
A large territory is required by cheselers to hunt for their prey.
They need to mark their territory in a way that will last for a while.
Hummingbirds are known to defend a small area because they depend on a small patch of flowers for their food.
Territoriality can occur during reproductive periods.
Seabirds have large home ranges of hundreds of kilometers, but when they reproduce they become fiercely territorial.
Each bird has a small area on the beach where they build their nest.
Foraging for food is when animals are looking for food.
An animal needs a food source that will give it more energy than it needs to get the food.
One study showed that shore crabs prefer to eat intermediate-sized mussels if they are given equal numbers of different sizes.
The net energy gained from medium mussels is greater than the net energy gained from crabs.
The large mussels take too much energy to open.
Foraging for food.
The highest rate of net energy return measured in Joules per second is provided by this size.
It can be shown that animals that take in more energy are more likely to produce more offspring.
If an animal forages in a way that puts it in danger and it is killed and eaten, it has no chance of producing offspring.
Animals face trade-offs that lead to modification of their behavior.
Many primate species are polygamous, meaning that a single male mate with multiple females.
Females tend to invest more energy in their offspring than males.
It is adaptive for females to be concerned about a good food source.
Females congregate in small groups around food sources that are clumped.
Males will attempt to defend the few females that are receptive from other males.
Males compete for the limited number of receptive females that are available.
There are New World monkeys that live in Central and South America.
One female mate with more than one male in a group of one or more families.
The fathers usually carry the twins when the female gives birth to them.
This could be the reason these animals are polyandrous.
The environment does not have enough resources to support several young at a time.
gibbons have a reproductive strategy.
Both males and females help with the rearing of the young because they are monogamous.
Men are often grooming and handling infants.
Prosimians, monkeys, and apes are mostly monogamous.
Monogamy occurs when males have limited breeding opportunities, territoriality exists, and the male is certain his offspring are his.
In gibbons, females are evenly distributed in the environment, which can lead to an increase in aggression between females.
Females will attack an electronic speaker if it plays female sounds.
Sexual selection favors features that increase an animal's chances of getting married.
These features are adaptive and lead to increased fitness.
Female choice leads to male competition in sexual selection.
It is more adaptive for females to be morechoosy about their mate than males, because most females produce a limited number of eggs relative to the number of sperm produced by the male.
The parents' fitness has increased if they choose a mate that will cause a male offspring to be chosen by other females.
Whether females choose features that are adaptive to the environment is questionable.
Peahens are likely to choose peacocks with the most elaborate tails.
A fancy tail could make a male more likely to be captured by a predator.
The daughters of a zebra finch underwent the process of imprinting after an extra ornament was attached to their father.
The females were more likely to choose a mate with the same artificial ornament.
Males don't have this certainty that their offspring is theirs.
Men often produce a lot of sperm.
The best way for males to increase their fitness is to have as many children as possible.
Competition may be required for them to gain access to females, and ornaments such as antlers can enhance a male's ability to fight.
A number of loud screams and grunts can be heard when bull elk compete.
The two bulls walk parallel to each other if a clear winner isn't found.
If one of them doesn't back off, the pair resorts to ramming each other with their antlers.
The intent of the fight is for one male to gain dominance over the other, not to kill his rival, although these encounters may have fatal consequences.
Evolutionary biology can be used to study social behavior in animals.
Sociobiologists think that living in a society has a better reproductive benefit than reproductive cost.
A cost-benefit analysis can help determine if the hypothesis is supported.
Group living has benefits.
It can help an animal find food.
A group of impalas is more likely to hear a predator than a single impala.
A would-be predator might be distracted by fish moving in multiple directions.
Weaver birds form giant colonies, which help protect them from predators, and the birds may share information about food sources.
A group of baboons signal to each other when they find a fruit tree.
Large prey, such as zebra and buffalo, can be captured by lions working together.
Group living has some disadvantages.
There can be disagreements over access to the best feeding places and sleeping sites when animals are crowded together.
Dominance hierarchies can be used to apportion resources, but they can also be used to disadvantage subordinates.
Among red deer, sons are preferable because they will result in a greater number of grandchildren.
For a longer period of time, larger sons need to be nursed more frequently.
Subordinate females tend to rear only daughters because they don't have enough food resources to adequately nurse sons.
Subordinate females in a red deer harem may be better off in terms of fitness if they stay with a group.
At the start of the breeding season, male bowerbirds use small sticks and twigs to build elaborate display areas called bowers.
They decorate the area with items that attract females and clear the space around the bower.
After the bower is complete, the male spends most of his time near his bower, calling to females, renewing his decorations, and guarding his work against possible raids by other males.
A female may approach the male.
He faces her, fluffs up his feathers, and flaps his wings.
The two will mate if the female enters the bower.
Males can mate with up to 25 females per year.
Biologists found that females preferred males with well-built bowers.
Male bowerbirds are not gaudy in appearance, but their displays are intense and aggressive.
Their displays are similar to those used by males.
Males can startle females if they are too intense too soon.
If females are startled, they may not be able to assess male traits.
Communication between the sexes might help maximize the benefits of intense male displays.
The degree of crouching reflects the level of display intensity she will tolerate without being startled.
By giving higher-intensity displays when females increase their crouching, males could increase their attractiveness without threatening the females.
The hypothesis was that males respond to female crouching signals by adjusting their intensity, and that a particular male's ability to respond to female signals is related to his success in courting.
It was not clear whether males were responding to females or vice versa, so it was difficult to measure a male's ability to modify his display.
A robotic female bowerbird was used to solve the problem.
Researchers were able to control female signals and measure male responses using these "fembots".
Male responsiveness to female signals may be an important part of successful courting.
Males that respond best under experimental conditions are more likely to startle live females.
parasites can easily pass from one animal to another and living in close quarters exposes individuals to illness.
Some of the proximity disadvantages are mitigated by social behavior.
Baboons and other types of social primate spend a lot of time grooming one another.
It is most likely that this will decrease their chances of contracting parasites.
Humans use extensive medical care to help offset the health problems that arise from living in densely populated cities.
"the other" is a behavior that has the potential to decrease the lifetime reproductive success of the altruist while benefiting the reproductive success of another member of the society.
In some insect societies, reproduction is limited to the queen and her mate.
Inclusive fitness suggests that relatives increase an individual's reproductive success.
When sterile nurses help the queen produce offspring that are related to them, they are being altruistic.
There are three sizes of sterile female workers in the army-ant society.
The smallest workers, called the nurses, are the ones who feed the queen and keep her clean.
Most of the population are intermediate-sized workers who go out on raids to collect food.
The soldiers, with huge heads and powerful jaws, run along the sides and rear of raiding parties to protect a column of ants.
The altruistic behavior of sterile workers can be explained by their fitness.
The genes are passed from one generation to the next in two different ways.
Direct is the first way to go.
The second way is if a relative reproduces and passes a shared gene to the next generation.
The queen of social bees is diploid, but her mate is haploid.
Sister workers will be related to each other if the queen has only one mate.
75% of their genes are the same as their father's.
It is possible for a worker to achieve a greater inclusive fitness by helping her mother produce additional sisters than by directly reproducing.
A behavior that appears altruistic is more likely to evolve.
Animals whose offspring only receive half a set of genes from their parents can be indirect selection.
Consider that your brother or sister has 50% of your genes, your niece or nephew has 25% of your genes, and so on.
If one sibling goes on to reproduce, the survival of two nieces or nephews is worth it.
In Africa, a female in estrus copulates with several members of the same group, and the males don't try to interfere with her.
Their apparent altruism appears to be related to their genetics.
Members of a group share more than 50% of their genes because they never leave the territory in which they are born.
In some bird species, offspring from a previous clutch of eggs may stay at the nest to help parents rear the next bunch of offspring.
A study of scrub jays in Florida found that the number of young produced by an adult pair doubled when they had helpers.
Pairs with helpers reared 3.6 pups in certain mammal groups.
While their mother is away, a meerkat is babysitting for their sisters and brothers.
The older meerkat's helpful behavior can lead to increased inclusive fitness.
Staying behind helps raise young.
A helpers contribution to the survival of its own kin is the first.
A nonhelper is more likely to inherit a parental territory than a helpers.
Helping involves making a short-term reproductive sacrifice in order to increase future reproductive potential.
In animals that are not closely related, helpers at the nest are also practicing a behavior called reciprocal altruism.
An animal helping another animal does not gain any immediate benefit.
The animal that was helped repay the debt eventually did.
Cheaters in altruistic acts are not appreciated in the future.
Vampire bats live in the tropics.
The bats share their blood meal with each other when they return to the roost.
If a bat fails to share blood with another bat that has previously shared blood with it, the bat that cheated will not be allowed to share blood in the future.
Experiments show that the nervous system controls behavior.
Human identical twins have been shown to have certain types of behavior.
The endocrine system controls behavior in marine snails.
The laughing gulls have a red bill.
As the chick learns, her begging behavior improves.
It shows an increased ability to recognize its parents.
The existence of a sensitive period, during which an animal is primed to learn, is one of the elements of song learning in birds.
In classical conditioning, two different types of stimuli cause an animal to form an association between them.
Dogs can be conditioned to salivate at a bell.
Animals learn behaviors when they are rewarded.
During migration, animals use the sun, stars, and the Earth's magnetic field.
Information is passed from one person to another in social behavior.
The exchange of information between sender and receiver is fostered by a variety of signals.
Animals have the ability to signal others without having to use chemicals.
The individual is expected to have an overall advantage due to reproductive success.
Animals have more energy left over when they choose foods that return the most net energy.
Animals use different reproductive strategies depending on the environment and social structure.
Males are expected to compete for female fertility.
Females are expected to bechoosy about their mates.
Living in a social group can give you advantages, such as being able to avoid predators, raise young, and find food.
Tension between members, spread of illness and parasites, and reduced reproductive potential are some of the disadvantages.
The benefits must outweigh the costs if animals are to live in groups.
This is a behavior in which an individual benefits the reproductive success of another member of society while limiting its own.
People help their parents.
Social insects help increase their mother's chance of reproductive success, but this behavior seems reasonable when we consider that siblings share 75% of their genes.
A parent's territory may be passed on to their offspring.
Pick the best answer for the question.
Any action that is learned is behavior.
One lovebird carries one strip at a time, while another carries several.
A diagonal line with an upward incline is what it would be.
A diagonal line with a downward incline is what it would be.
The development of singing patterns in white-crowned sparrows is influenced by social experience.
Birds were trained to sing by other birds.
When birds learned from tape recordings, the period in which they learned from other birds was larger.
Match the type of communication in the key to the description for the questions.
Answers can be used more than once.
When aphids sense they are in danger, they release an alarm pheromone.
Male peacocks have elaborate displays of feathers to attract females.
Squirrels make an alarm call to warn others of a predator.
Male silk moths are attracted to females by releasing a sex attractant.
The segull grouses perform a dance.
Territoriality gives all of the benefits except access to mates.
The observation that male bowerbirds decorate their nest with blue objects is associated with insight learning.
Some members of a population act as sentries and exhibit altruistic behavior.
Different chemicals used in our environment have been shown to disrupt the production of pheromones in animals and humans alike.
If a colony of bees were exposed to a chemical, the consequences could be dire.
There were a number of incidents in which 5-ton orca whales appeared to attack their trainers.
Many people are questioning the ethics of keeping animals in captivity.
Some people think that freedom is never absolute.
An animal in the wild is restricted by its environment.
Nowadays, zoos and aquariums usually get their animals from other facilities.
Most people don't think taking animals from the wild is a good idea.
Zoos and aquariums should not be involved in the illegal trade of wild animals.
Today's zoos and aquariums are more involved in the care of animals than they were in the past.
While animals are recovering from injury or increasing their numbers until they can be released back into the wild, they provide the best home possible.
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