In the Origin of Species, instinct in not clearly defined by Darwin in chapter 7. He believes the attempt to define instinct in not something required because everyone either knows it or not. Essentially instinct is an action. Actions need requirements, those are: done without experience, action is done in the same way, and done without knowing the purpose or end goal. However, the requirements for action are not universal for instinct because of reason and judgment, these are factors towards those actions. Darwin begins to acknowledge the difference between habit and instinct. The two can actually be confused with each other. Since both habit and instinct have repeated actions, they seem to be the similar.
The difference between the two is that instinct contains inherited actions while habit contains learned actions. He uses the remaining of chapter 7 to differentiate the two with examples. The first example he mentions is the caterpillar hammock. Caterpillar thoughts seem to be habitual. They create hammocks that are very complicated. If the caterpillar completed its hammock, and its placed at the 3rd set, it will continue to finish the hammock out, but if it was on the 3rd and was moved to the 6th, it will feel the need to go back and finish. They essentially feel “Forced to go back and finish the train of thought” (Chapter 7).
Which in turn, this refers to either habit or instinct. According to Darwin, both habit and instinct are very similar that it may become hard or indistinguishable. In order to fully understand what instinct really is, natural selection is mentioned. Natural selection leads to variation but also preserves that variation within instinct. Instinct can arise through “slow and gradual accumulations” (Chapter 7), rather than through natural selection. Darwin’s theory is that “The instinct of each species is good for itself, but has never as we can judge, been produced for the exclusive good of others”. This theory shows that instinct only benefits the user and not others. In further examples, this theory changes.
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The next example that Darwin mentions to differentiate instinct and habit is about the ants and aphides. The Aphides represent instinct. Aphides are an example of a species that do not show that their instincts are good for themselves, but rather for others. Darwin experimented with these aphides. They are prone to excrete, and he artificially tickled and stroked their hair; however, there was no excretion. He then allowed the ants to approach the Aphide, which then the aphide began to excrete. The ant consumes the excretion. This ‘instinct’ gave beneficial use to other insects, which in turn does not support his theory; however, his conclusions exemplify that the action of the excretion is instinctual, convenient for themselves, and not only for the sole purpose of the ants.
“Accidental variations’ are displayed in domestic instincts. Domestic instincts are ancestral instincts that an animal could have that was passed down generation after generation. For example, dogs and wolves share those domestic instincts. Hunting, pointing, and retrieving are good examples of domestic instincts. These qualities are comparable between many and yet young dogs, making them instinctual. These ancestral instincts are long term instincts that are acquired. Natural instinct and domestic instincts are similar; however, natural instincts are lost through habits in each generation. This has been done through selections by man and by the loss of those through generations.
The Cuckoo also displays instincts. The female cuckoo’s lays her eggs in other bird’s nests. This is an instinct of theirs. Behaviors change over time, such as the raising of their own or becoming a brood parasite. By these birds laying their eggs in other birds’ nests, it has become instinctual, and is not a habit. Most cuckoos raise their own offspring, and some do not; the reasoning to this is because their behaviors change throughout generations. Through close observations, the Cuckoo actually produced this instinct. This instinct arose from habits that the young observed through their mothers. Can habit generate future instincts?
Slave making instincts were first observed by Pierre Huber. Ants are the main species that show that these instincts are boldly expressed. Ants always depended on their slaves to care for them. The “master” is dependent on its slave ants. The large master ant is red while the slaves are small and black. Once they are born, behaviors are not learned, they are instinctual. These instincts are communicated to the rest of the population, to care, feed, and carry them. All of the slave ants are worker ants.
The next set of instincts that Darwin mentions is the Cells of the Hive Bee. The bees create hexagonal cells that are double layered and are made for the sole purpose to hold as much honey as possible. While another bee species, called the Mexican Melipona Bee, is a cross between the Humble Bee and the Hive Bee. Their method to create cells for their honey is quite different. They make circular cells that are not connected with one another. Darwin then created his own Bee research; his hypothesis was that the hive bee while undergoing natural selection, obtains their instincts of building. There are three main steps to this research: 1. He separated the combs with strip of wax, 2. Separated combs with vermillion, 3. Then he observed bees continuously moved towards problems in the same way, which insinuates that it is instinct. Natural selection refines instincts to make them more advanced.
The last type of ‘instinct’ in chapter 7 pertains to neuter insects. These insects are sterile females. Instinct is degenerated differently through sterile insects.; however, their instinct to reproduce is diminished. They are very beneficial to the community because they become opted to work rather produce. There are 3 castes: males, females, and workers (sterile females). There are also body structure differences within the three castes. Their body structures change, even though their genes are passed to them, how do their genes continue on through generations if they are sterile? Natural selection for sterile genes are done to the whole of the population rather than the individual. Therefore, the sterile insects are the working class of the population.
A point of discussion in chapter 7 is how habit evolved into instinct. The instinctual parasitism of the Cuckoo arose from habits. The cuckoo is a brood parasite. Brood parasites are clever, and direct the host to raise their young instead of the host taking care of their own. These parasites do not raise their own offspring, losing any maternal care that they could have. These mothers also remove the eggs of the host so that she can place hers in the nest to be taken care of.
The host will then take care of the cuckoo’s offspring as her own. Parasitism evolved within this species through the changes in their eggs sizes, diet, and migration (Davies NB). Seems to show that habit was learned through each generational period. Their habits are well known to scientists today (Glue and Morgan). Each action that they do references back to habit. Studies show that brood parasites are very good examples for species interactions. The host bird and the parasitic cuckoo are in a parasitism state. Which then also leads to the differences in natural selection. The Cuckoo’s characteristics begin to change in order for their host to not recognize that cuckoo’s egg is their own egg.
The color and slight size changes are physical characteristics that change so that the host can raise it as their own. This is known as egg mimicry. Female cuckoos change their egg color in preference to the host they most favor. (Brooke and NB Davies). Due to rejection of the cuckoo’s egg’s by possible hosts, the cuckoo has evolved to mimic the hosts eggs in color and size. In an individual setting, female cuckoo’s can only mimic the eggs of local hosts, not of all hosts (Aviles). The cuckoo’s habit in performing these actions, has equipped to becoming part of natural selection the use of evolution. This leads to how habit has become an instinct for future cuckoo generations.
The cuckoo is a great example showing how habit can generate There are many other examples into which habit is learned and becomes instinct for other animals. Through Lamarckism, animals can pass down their habits into something inherited to their offspring. Social learning is a theory in which an animal can acquire their behaviors based on observations or habits. In a given moment, animals can test their behaviors, and wait for either positive or negative feedback (Reisman). An example of this can be found in monkeys. The mothers eat certain foods, ones that are essentially good to eat, and teach their young which foods to eat. The more the mothers eats the particular food, the more the young observe this behavior.
Through their observations, they also begin to eat that same food frequently. Their successive eating behaviors are attained and then inherited to following generations (Jablonka). How cuckoo’s can change their egg color, physical variation occurs. In giraffes, this is the same, the habit to reach for tall trees to feed, increases their offspring’s actions to do the same. Their sequential generations evolve to be born with longer necks. Through habit, instinct has different variations, either mental or physical (Gould).
It is clear that instinct and habit are similar but through generational periods and paternal care, one can see that they are distinctively different. To mention again, habit is learned while instinct is innate. The heritability of behaviors, if those behaviors come from instinct or habit, does not matter because those behaviors pertain to the species themselves and to the population. Darwin express great curiosity towards innate behaviors. Innate behaviors are behaviors that you are born with but how did those behaviors become innate?
Did they become innate based on previous habits of their parents or become innate through something like domestic instincts? Only through natural selection, these can be answered. Although instinct is very complicated to understand, the examples he describes in this chapter are about the cuckoo, caterpillar hammock, ants and aphides, and the sterile workers; demonstrate how behavioral genetics works.
These examples in themselves are complex, but each animal species have distinct purposes to survive. These variations show the differences in generations and how or what was inherited. Darwin believes that instincts, compared to other features of animals, is the most important. Habit is also involved in animal inheritance; however, instinct is what develops at birth and generates the animals’ behavior at an early stage. The behaviors given by instinct can benefit or harm others. By the cuckoo removing the hosts eggs so that her offspring can survive provides a negative effect to the host. The aphides producing the sweet ejection for the ants is beneficial. The caterpillar’s hammock and train of thought is neither beneficial or harmful to itself.
The last example is the slave making ants caring for their masters, this evidently shows a beneficial factor to the other species but a negative effect to the slave ant. Instincts evolve through generations, Darwin did not know that this was the case through genetics, he only observed that behaviors were actually passed down to next generations. Either it may be instinctual behaviors or habitual behaviors, they seemed to be passed down. The behaviors that are passed down are the one that will provide the species to have the best and strong qualities compared to their ancestors. Through natural selection and genetic variation, species undergo an advancement to survive and live long.
