How does natural selection apply to humans? The fields of Biology and Psychology diverged instead of coming together as Darwin once thought they would.
John Broadus Watson symbolized the behaviourist approach and that psychology should not concentrate on its concern with unobservable entities such as minds and feelings. Both animals and human psychology should abandon any reference to consciousness and stess the importance of environmental conditioning. Watson was in opposition with Darwin and was very anti-evolutionary and anti-hereditarian when it came to human behavior.
William James looked at animals for the instinctive roots of human behaviors and morality and noticed they were modified by experience. Francis Galton associated the ideas of heredity and instinct with dangerous political thoughts. They misinterpreted the science and used it to their advantage. The thoughts such as, care for the sick and needy led to the procreation of the less fit, gives a crazy outlook on behavior. The thought was brought up that the STATE should INTERVENE to modify human mating choices. The eugenics movement was born from these thoughts. This lead to some practiced in the United States such as compulsory sterilization and restriction of immigration.
Evolutionary Psycology thought that there was an environmental connection to evolutionary adaptiveness and that module-based capabilities in the brain evoled. Nearly all sociobiologist and evolutionary psychologists now assert the psychic unity of mankind, regaurdless of race or ancestry all human’s cognitive make up are the same, are not our of political correctness.
Evolutionary Pschology versus Human Behavioral Ecology/Sociobiology
What is the Modular Brain Concept? It is the differenct components of the brain deal with different specific functions, such as, vision, hearing, talking. Perceptual modules operate quickly, immune from interference by memory, experience or reflection.
Because it tastes good! Most people have a taste for sugar. Well, why do we like sugar? Physiologically we can answer that question by looking at the receptors to the brain. The neurological path tells us that this tastes good. This is a mechanistic reasoning.
These questions can be answered proximatly, the here and now, or ultimate, evolutionary history. The proximate analysis deals with how genetic-developmental mechanisms inflluence the assembly of an animal and its internal components. Proximate analysis also deal with neuronal-hormonal mechanisms which develop within an animals lifetime that control animal behavior. The ultimate analysis deals with evolutionary history of a species and their adaptive values.
The Ultimate Analysis
The selection and adaptation of a species will determine the cause for certain behaviors such as manogamy. In Praririe voles, the evolution history shows that their decendants were first polygynous, but their manogamy developed overtime. This could probably be due to female sparceness.
The Proximate Analysis
At the proximate level we look at the hormonal-nervous system mechanisms. In Praririe voles, bonding of vasopressin with receptors triggers chemical activies that affect neural pathways. This provides the males with positive rewards. The rewards cause males to stay near one female. It is a proximate cause for manogamy.
The Proximate Mechanisms
The mechanisms of proximate causes include neurophysiology and genetic activity. The key sensory, environmental, inputs must cause some gene activity and produce changes in biochemistry. The biochemistry alters neurophysiological mechisms that lead to learning.
What are the Advantages and Disadvantages of Learning?
The disadvantage of having to learn a skill is that it takes a lot of time and energy. This lengthen the time it takes to be ready to do the actions this skill requires. The time, energy, and neuromechanisms used for learning means you can’t use those things for other activities.
The advantages of having to learn a skill are vast. These advantages inclue being able to match the skill to the social environment.
Nature vs. Nurture
The development of and organism is an interactive process. The genes and environment is continually interacting throughout the lifespan of the organism that cause changes. The genetic information interacts with changing internal and external environments. The genes are either turned off or on by signals. These signals are internal, cellulcar, chemical or external environmental stimuli. The interactions alter the assembly of the organism, its neural network, as well as other aspects of its physiological or anatomical systems.
DNA IS BOTH INHERITED AND ENVIRONMENTALLY RESPONSIVE – Gene Robinson
In this class we take a look at the reproductive control males and females try to have over the fertilization of eggs. These topics are varied and vast.
Sperm competition is more actively controlled by the animal that is involved. There is a variety of ways that males and females try to have the upperhand in fertilization. This occurs in insects, birds, and a variety of other species.
Males and Females can remove sperm from individuals. Some females will store sprem and control which sperm is fertilizing their eggs.
Mate Guarding Males
Males will gaurd the female, so that they will control female permiscuity. If a male can gaurd another male’s access to the female, then they can be sure their genes will make it into the next generation.
In spiders there is a step up from this mate guarding. Male spiders will produce sperm in their abdomin and use a petipalt to transfer the sperm to the female. The female will store the sperm. The male will break the palp off and it will act as a plug to the females sperm storage area.
This brings up the idea if females are choosing mates on quality.
Key ways the Males and Females try to Control Reproductive Decisions
Male Control:Resource Transferred to Female, Elaborate Courtship, Sexual Coercion, Infanticide.
Some species, one sex consumes the other sex. In sexual cannibalism, there is a subgroup of sexual suicide. The female gets a nurtitional resource. The short length of their life and the small chance of finding a mate leads to a reason why this sexual suicide makes sence.
Good Parent Theory
Females prefer to mate with males that provide more paternal care. Male courtships is linked to his parental abilities. (15- spine stickleback)
When we look at species with ornamental features the question that is brought up is do these ornamental features mean good genes? Is the male healthier? In some species, we see there is a correlation between the beauty of the ornamental feature and offspring health, but this is not always the truth. This is runaway selection. Runaway Selection is an evolution sensory bias of the female the excentuates the feature.
The female mare choice genes and the genes for the prefferred male attribute are inherited together. The daughters inherit the genes for the mate preferencec, and the sons inherit the preferred attribute. The males attract more females with the preference, and the mate preferrence takes on a life of its own. Even when the male do not have the best genes.
Chase-Away Selection Theory
This theory is explained by sensory exploitation. The initial sensory exploitation is started by the viability selection on female sensory systems. The female attration for a male trait from a preexisting bias. This mutation produces a rudimentary male display trait to exploit the females preexisting bias.
The females fitness declines due to this change, so the female mating threshold increases. The male attraction decreases, so the male attractive trait increases and this becauses a circle.
There are a variety of ways that sexual conflict that can occur between males and females.
In this class we discuss the different aspects of foraging and sexual reproduction in the animal kingdom.
Foraging Behavior Aposematism Aposematism is a coloration of an individual that repels predators. The formation of this color repellent was able to evolve because the individual who was wounded did not die, but was not eaten. This individual was able to pass on its genes. The predator also needs to be able to remember that the color mean toxic.
Optimal Foraging In optimal foraging you are going to get the most amount of food for the least amount of energy. This also increases the energy available for reproduction. The optimal foraging theory predicts than an animal should behave in a way that maximizes the benefits, minimizes the costs, and in turn will maximize the net energy gain.
We can look at various species to see if they are foraging optimally. The main thing that could determine the ability to forage optimally is the present of a predator. This will push the individual into a sub-optimal environment.
Profitability of Prey Profitability of prey is the energy gained per unit of handling time. An example of the reduction of optimal foraging is seen in young garden skinks. Their foraging success is lowered in order to reduce the risk of predation. When the number of there are predators sensed there are a smaller number of active lizards, but when you have coverage by a micro-habitat the percentage of lizards that are active increases.
Alternative Foraging Strategies
Frequency-Dependent Selection Frequency-dependent selection is genetically based strategy. As the percentage of a prey species with a specific trait increases overtime it will be consumed more of the time. The predator will eat the more common morph. So, overtime as the the abundance morph will start to decrease, and the other morph will increase. The genotype with a rare genotype is less likely to be consumed. As oscillation of morph frequency will become apparent.
Example: The percent frequency of a blue morph butterfly is larger than an orange morph butterfly. As the more abundance blue morphs are being predated upon, the orange morph will produce more offspring and become more and more frequent. The blue morph becomes more rare because of predation, and the orange morph is more frequent. The predator will then consume the more frequent orange morph. The blue morphs will then be able to reproduce more while the orange morphs are being killed. The occilation of morph frequency starts to appear.
Conditional Strategies Conditional strategies are an inherited mechanism that give the individual the ability to be flexible. The foraging strategies shift from being a predator, competitor, scavengers or commensals. The behavior depends on the environment, but the mechanism to be flexible is genetically inherited.
The Evolution of Reproductive Behavior
Sexual Selection Sexual selection involve traits that lower survival, but enhances the ability to mate. Sexual selective traits are anything that increases the chance of an individuals getting their genes into the next generation based on their ability to mate. The trade off with the increased ability to mate is with its survival ability. The traits can increase their chances of being predated on, decrease foraging ability, ect.
The variation in reproductive success is greater for males than for females. There are a few individuals who get most of the mates, and many individuals who never mate or mate infrequently as a male. The female do not vary as much in how many times they mate, or how many mates they have. The theory of the variation between males and females are the cost of their gametes. The female have fewer and less frequent production of the egg, and at a higher energy cost. The males produce many sperm and will mate with many individuals. Females will be choosy. This produces a conflict between males and females, the operational sex ratio.
Operational Sex Ratio
The actual sex ratio in the field is 50/50 between males and females, but the operational sex ratio tend to be heavily male biased. That means there are a lot more males running around that are sexual active. The females, once their eggs are fertilized, will stop looking to take care of their egg. This male biased ratio is very common.
The operational sex ratio can be reversed where the ratio is heavily female biased. This can occur when males are focused more on other survival behaviors like foraging.
The Preference of Isopods to Non-Saturated, Partially Saturated,
and Fully Saturated Moisture Levels in Sand
Methods and Materials
An artificial habitat was established in a 10.5” x 5.5” clear Tupperware container containing large granule beach sand. The substrate was sectioned into 3.5” x 5.5” areas using plastic dividers between sectors. The plastic dividers touched the bottom of the container to approximately ¼” under the substrate surface. This method of using plastic dividers was used to prevent transfer of water across the three regions.
The three sectioned areas were each treated with different levels of increasing saturation. The first section did not have any water added to the substrate, the second section was partially saturated with 150 mL of water, and the last section was fully saturated with 300 mL of water.
Figure 1 The habitat set up and three treatments are shown. From left to right saturation levels; 0 mL, 150 mL, 300 mL, of water.
A total of six individuals were observed over 60 second time intervals. All individuals were initially placed in the middle area with the 150 mL saturated substrate. A acclimation period of 30 seconds was provided for the isopods to have a chance to move around before data was recorded.
Collection of Data
The six individuals were separated into two observation groups. One individual in each group was assigned to an observer to record movement data. The observer recorded how much time each individual spend on each substrate over the 60 second interval. The data set for all individuals were compiled and used in a statistical analysis to determine moisture preference.
The behavioral response of the isopods’ preference to moisture was tested using the non-parametric Kruskal-Wallis statistical test. The time spend on different substrates by individuals were ranked. To test the hypothesis that isopods prefer moist environments the longest time spend on a substrate was ranked as number one and decreased as time on substrate decreased. The calculated h-value from the test was compared to find significance level.
Observed data from each individual was arranged and ranked as shown in Table 1. The isopods overall spent more time on the substrate saturated with 300 mL of water. The R-values calculated for the Kraskul-Wallis test demonstrates the findings that isopods spent more time on the 300 mL saturated substrate. The R-values were calculated in a way that the higher the rank, the more time, in seconds, the isopods spent on the substrate. A high rank meant that the isopod spent the most time on that level of saturation. Table 1 shows that the R value of the substrate saturated with 300 mL had the highest ranking. This supports the hypothesis that isopods prefer moist environments.
Substrate Saturation Levels and Ranks
Seconds Individual Spent on Substrate
Table 1 The ranking of time for individuals are established on the basis that the longer an individual is on a substrate the higher they are rank. The data points for each individual’s time on a different level of saturated substrate is listed with their ranks. The R- value relates to the ranking of time spend on one saturation level by the six individuals. The lower the value of R the longer the individuals stayed on that saturation level.
The substrate saturated with 0 mL and 150 mL of water were more closely ranked. However, the substrate with no water was ranked higher than the partially saturated substrate. A H-test was used to calculate the level of significance for these findings. The calculated h-value was 6.75. This value was compared to non-parametric ANOVA for samples with 6 individuals. The calculated value supported that the data was significant (p=0.05, when h>5.801, our h=6.75). These results show that there is a significant difference from the null hypothesis and there is a preference in isopods to different moisture levels.
In this lesson we start to analyze animal communication. Communication can take place between the same species (conspecific) or different species (heterospecific). Communication systems will continue as long as signalers and receivers gain fitness benefits from the interaction. There ware a variety of modalities for communication including; visual, chemical, auditory, electrosensory, and mechenical sensory. A resulting modification of communication is sensory exploitation.
In sensory exploitation, one individual sends a signal that activates a preexisting sensory emchanism already present in the reciever. An example of this can be seen in male cichlid fish. The males (signaler) possess large orange spots on its anal fin. The female (receiver) has evolved to brood her eggs in her mouth. Since the large orange spots on the males anal fins look the same as her eggs she will get close to his anal fin to pick up what she perceives to be her eggs. At this moment the male cichlid will release sperm into the females mouth hoping to fertilize the eggs she has already picked up.
This trait does not reduce the fitness of the female. Infact, by the fetilization of her eggs her genes are able to be passed on. This can explain why nature has selected for this trait. It has a benefit to the male and the female cichlid.
Another ‘colorful’ example of this sensory exploitation is the Orchid mantis. The ornate colors of the mantis attracts insects to him. The insects link color to nectar-filled flowers, hence their attraction to the Orchid Mantis.
Harmless Threat Displays
The majority of species will put on a harmless threat display. This saves the individual energy and minimizes the risk of injury from fighting. The barking gecko is a darling example of this sensory communication behavior.
1. Explain the extra androgen hypothesis and evidence that support or refute it.
The extra androgen hypothesis states that the Psuedopenis is cause by developing females with high levels of testosterone. The clitorus and penis are made from the same embryonic tissue. The reason that it is either a penis or a clitorus depends on the androgens the tissue is exposed to. However, studies have shown that pregnant females giving a androgen receptor antagonist had little effect on the daughters Psuedopenis.
2. Give some alternate explanations for how the Psuedopenis may not be adaptive.
When hyenas greet each other they inspect anogenital regions. Hyena females are more dominant than males. During a greeting of two females, if one female has a Psuedopenis she may not be perceived as dominant. Hyenas with a Psuedopenis also produce high androgen levels that increases her size and aggression. This makes her an alpha, and alphas cubs get more food.
3. How could sensory exploitation play a role in the adaptive origin of the Psuedopenis?
Sensory exploitation plays a role in the adaptive origins because of the social greetings that hyenas already possess.
4. What is one possible adaptive value of this structure that doesn’t support sensory exploitation?
One possible adaptive value of this structure that doesn’t support sensory exploitation is the increase of testosterone that makes these females more aggressive. This behavior enables them to increase their fitness, but makes are seen as weaker. When greetings occur they are perceived as the weaker sex.
Animals engage in various kinds of social interations. In this lesson we learn about the breeder/helper social behaviors of animals. This includes primary helpers and secondary helpers as they relate to altruistic behaviors between individuals.
There are individuals known as breeders and helpers in groups of various species. The helpers can be categories into two differet groups, primary and secondary. These forms of altruism are more common than reciprocity because individuals who participate in reciprocity run the reick of never being repaid. This careful calibrative altruism to relatives will be repaid. An alternative to the helpers are known as delayers. They do not help or mate and will wait until the next mating season. For example, a male pied king fisher who can not mate can either be a primary, secondary, or delayer.
The primary helpers will help relatives. This increases their indirect fitness since they are helping relatives with the same genes. Seconday helpers will help non-relatives. This is possibly because of post pone cooperation. The seconday helper will hope to inherit the mating site and this leads to direct fitness. The evolution of this seconday help has been promoted by natural selection due to it gain in direct fitness for helpful individuals. The delayer will not use any of their energy to help relatives or non-relatives and will wait until the next season to mate.
Altruism differes between vertebrates and invertebrates. Vertebrate are involved in facilitative altruism. This type of altruism is flexable or opertunistic in nature. Invertebrates are involved in obligate altruism. This form of altruism has such a long standing pattern of favorable conditions for eusocialism the workers have to work through evolution.
Environment vs. Genes for Behavior
Cooperative breeding is linked to monogamy because there is more relatedness in cooperative groups.
In this lesson, we explore why animals live together in big social groups, and why others do not. At the end of the class we collect behavioral data on meerkats (Suricata suricata), and white-cheeked gibbons (Hylobates concolor) using instantaneous and continuous sampling. Lab Questions are answered at the end of class notes along with a link to my raw data set.
A pack of wolves, a group of orca whale, a pride of lions; why do some animals live together in a large group?
Leopards, praying mantis, red pandas; and why do some animals find it better to be single?
Animals interact in a variety of ways, the key to what works is what will benefit the individual the most, and you better beleive these benefits must outweigh the cost. Advantages of living in a large group gives you better defense against a predator, mutual defense, and can make hunting pray easier, but living with others doesn’t come without its disadvantages. Diseases can be passed easily when more individuals are around, and with more individuals it does become harder to be inconspicuous to your predators. The competition for resourcses, such as food and mates, becomes higher. Its easier to catch a mate if you are the only one there…
When you live in a group helping out can be a huge benefit to the individual. This discussion focuses on three main topics; cooperation, post poned cooperation, and reciprocity.
A simple way to explain Cooperation is when two individual both benefit from helping one another.Ex. Individual A (the helper) and individual B help each other right now and they both gain direct fitness.
Post Pone Cooperation
Post pone cooperation is when an individual eventually gains access to a resource controlled by another individual because of its prior help.
Reciprocityinvolves a interation where the individual was helped directly pays back the individual who helped them.
In your write-up, include copies of your data sheets, and those of your partner or a member of another group. Please address the following points.
1. The similarity between observers is called interobserver reliability. How similar were your observations to another student’s observations? How similar were they to the “researcher sample” observations?
When comparing my observations to Alex’s they were very similar, but did posses some differences. There was a variation of the times were we detected change in events in the gibbons, but what we perceived the subject to be doing were the same. We also had slight differences in the meerkat observation as to how many meerkats we thought were moving as opposed to foraging, and what we understood to be the act of being a sentry.
2. How do you explain any observed differences? Why is it important to minimize these? What could you do to maximize interobserver reliability?
Differences in observations can be attributed to many things. A key factor is viewer perception and perspective. If two observers were watching the meerkats as they scan and one meerkat is sitting on a rock the observes could perceive this in different ways, one may think that the meerkat is sitting up on its feet enough to be a sentry while the other observer things that the meerkat is resting. Another factor is the perspective of observers. If one sees the meerkat from the back hunched over one could think he is resting, but if one sees the meerkat from the front and can see it diggin, then they would mark him down as foraging. Finally, differences can come from the understanding of what can be described as each event. It is important to minimize these differences in observations, so that data can be consistant. To maximize interobserver reliability, each participant should be strictly guided on what they are looking for when deciding what event has occured.
3.Do you think it is possible to eliminate all interobserver variation? Elaborate.
I do not think it is possible to eliminate all interobserver variations because there will be some disagreements on what another observer has seen. There is always the chance one observer was not looking where or when the action happened.
4.What was the percent agreement calculated from the mock data?
The percent agreement calculated from the mock data was 0.9 or 90%.
5.What sort of questions about meerkat behavior could be addressed with the type of data that you collected? What about the gibbons?
The kind of questions that could be addressed with the data collected about the meerkats include; how many meerkats can feel comfortable to feed with one sentry, will the meerkats take turns being sentry, what other events happen during this time, how long does an individual stay at attention? For the gibbons questions the data addresses questions such as; how long does the baby gibbon move around before it needs to rest, is there more interactions between the baby gibbon and the mother or the father, what kinds of interactions are done more with the mother/father?
In this lesson we explore altruism; its meaning, evolution, and helpful terms. Reflection questions are explored at the end of the lesson involving hymenoptera, eusocial speccies, and factors that led to the evolution of eusocial’s extreme form of altruism.
Ground Squirrels: The squirells were making a high pitch noise when predators were present. Why would the squirrels make this noise that would alert predators to their location?
Weaver Ants: The ants were holding leaves together to form a bridge for the worker ants to move across. Why would the ants express this behavior?
In the eusocial Hymenoptera, a order of insects including bees, ants, and thousands of other insect species, consist of individuals unable to pass on their genes due to various reasons. In the case of the weaver ants, most of the ants are sterile. So, How can these individuals pass on genes if they are unable to reproduce?
To investigate this questions we must understand altruism and the altruistic behaviors these species manifest. Altruism can be defined as the helpful behavior that lowers the helper’s reproductive success while increaing the reproductive success of the individual being helped. The ultimate puzzle og the evolution of altruism was questions by Darwin. If the self-sacraficing altruists were unable to reproduce it would be a logical assumption that this behavior would be naturally selected against and should disappear over time. So, Why have altruism evolved and not been selected against?
A number of rationale have been theorized to answer this questions including; intelligent disign theory, group selection, indirect selection, and kin selection. Animal Behavioralists tend to employ kin selection theory. This theory have been proven time after time to be useful for scientific investigations. “Kin selection theory has been used to show altruism can spread through a population if the cost to the altruist in terms of a reduction in the number offspring produced [multiplied by the coefficient of relatedness between the altruist and those offspring] is less than the increase in the number of related individuals helped by the altruist [multiplied by the average coefficient of relatedness between the altruist and the helped relatives].(Animal Behavior, John Alcock)”
Exploring this theory further we must know specific terms including:
Direct Selection: Acts on traits that promote success in personal reproduction
Direct Fitness: A measure of personal reproduction (your own offspring that survive and reproduce.)
Indirect Selection (Kin Selection): Acts on traits that promote success in the reproduction of nondescendant relatives.
Indirect Fitness: A measure of the number of relatives that the altruist helps to survive and reproduce.
Inclusive Fitness: Direct Ftiness + Indirect Fitness (A total measure of the genetic success of an individual)
An altruist can promote transmittion of their genes indirectly by their behaviors helping a relative. Kin or Indirect Selection results in a increase of genes transmitted indirectly by an individual to the next generation in the bodies of relatives that exist because of the altruist’s help. The Kin selection theory underlies modern “gene-centered thinking.”
Individuals should behave in a way that boost their inclusive fitness (defined above), this is achieved by self-sacrafice or self- serving conflict with others.
Who would an individual be more inclined to be altruistc towards?
This question can be easily answered in a quantitative sense. Imagine a woman is left to raise 2 nephews and 1 neice. Would it be more benefitial in terms of fitness to raise 1 child of her own or these 3 nephews/neice?
Upon review of the picture above we can see that from one child the woman would have .5 direct fitness and from 3 nephews/neices she would only have .375 indirect fitness. Since .5>.375 it would be more benefitial for the woman to raise her own child.
What are Hymenoptera? Hymenoptera are “membrane winged” insects which include; bees, ants, and wasps. There are over 150,00 species of Hymenoptera
What are some main characteristics of Eusocial Species? A Eusocial Species is the highest level of organization of animal sociality. The characteristics they possess include; cooperative brood care, overlapping generations within a colony of adults, and division of labor.
What factors led to the evolution of this extreme form of altruism? In a paper written by M.A. Nowack, ‘The evoltuion of Eusociality.’, the evolution of eusocial species are lead by five factors. The first is a formation of groups this leads to the next factor that the occurance of preadaptive traits caused the groups to form tightly giving the colony a valuable and defensible nest. Appearances of mutations also caused the persistance of the group, silencing dispersal behavior. Natural selection by environmental factors shaped the emergent traits caused by interactions of the group members, and multilevel selection drove changes in the colony life cycle and social structure.
Nowak, M.A., Tamita, C.E., & WIlson, E.O. (2010). THE EVOLUTION OF EUSOCIALITY. Nature, 466(7310), 1057-1062. http://doi.org/10.1038/nature09205