Chapter 1- Introduction Flashcards
The tendency for characteristics that contribute to the survival of a species to persist, and for those that do not to disappear
Natural selection
Darwins theory was published in 1859
He did not understand the genetic basis of variation. Gregor Mendel discovered the genetic basis for natural selection
Darwin gave examples in nature: how animals coats get thicker when the climate turns gradually colder
Describe Richard Dawkins pebbly beach analogy
In a pebbly beach, the pebbles are not arranged at random, the smaller pebbles tend to be found in segregated zones running along the length of the beach, the larger ones in different zones are stripes. The pebbles have been sorted, arranged, selected, but without intelligent intervention. It is from the mechanical, unthinking force of the waves as big stones and small stones are affected differently by the waves and end up in different places
Describe the evolution of characteristics of the peppered moth
Feeds at night and rests during the day on the trunks and limbs of trees. Survival depends on its ability to escape detection. At one time these moths were a mottled light gray colour which resembled the lichen-covered trees, and a rare black variation stood out against this background which made it highly vulnerable. Pollutants in industrial areas killed the lichen and a darkened the bark of trees, which made the light coloured moths fall more increasingly as prey, whereas the dark moths tended to survive and reproduce. Near industrial centers, the black had increased in number and the light ones declined
Describe the grants study of the finches of the Galápagos Islands
Two species of finches ate the Caltrop seeds , The ones with the beak 11 mm long could crack the shell, and ones with a beak 10.5 mm long could not. During severe drought when the seeds are the only food available, the average beak size increased as birds with smaller beaks died off but when the rains finally returned and larger seeds became harder to find, the smaller beak birds had the advantage
Significance: small differences and changes make big differences. Depends on the changes in the environment
Any change in a gene. When the modified gene occurs in a reproductive cell, the mutation may be passed on to offspring
Mutation
A relationship between a specific event and a simple, involuntary response to that event. Usually refers to an unconditioned one
Reflex
Describe the reflexes that exist in the amoeba
Protects the amoeba from injury by immediately withdrawing from noxious substances. Minimizes the harmful effects of the substance
When encounters some edible objects, it immediately responds by engulfing it and making a meal of it
Describe the salivary reflex
Important for food consumption. The flow of saliva that begins the process of digestion and trigger swallowing
When reflexes fail to function properly. It may happen as a result of an allergic reaction to medication or as a result of injury or disease or in people who have consumed excessive amounts of alcohol or other drugs that depress the central nervous system
Reflex failure
Example: death from alcoholic intoxication when alcohol interferes with the respiratory reflex or when the intoxicated person vomits inadequately and chokes to death
An increase in the intensity or probability of a reflex response resulting from earlier exposure to a stimulus that elicits that response
Sensitization
Describe Powell and Holtzmans work that illustrates how sensitization works in the context of drug addiction
May play a role in drug addiction. Animals given an addictive drug over a period of time are later more sensitive to their effects. Gave rats morphine for 1 to 2 days and then tested their reaction to the drug after a period of abstinence. The rats showed an increased response to morphine, sensitization, for up to three months after their last dose
A decrease in the intensity or probability of a reflex response resulting from repeated exposure to a stimulus that elicits that response
Habituation
When babies first hear a noise they respond with an increase in heart rate but with repetition of the noise at regular intervals, the change in heart rate becomes less and less pronounced until in some cases, the noise has no measurable effect at all
What is the relationship between fetal habituation and intellectual development after birth
Slow fetal habituation tends to be associated with difficult pregnancy, and there is some evidence that the rate at which a foetus habituates is correlated with intellectual development after birth and may one day be used to identify prenatal medical problems
Who originally said that change is the only constant?
The Roman philosopher Lucretius 2000 years ago
The world is constantly changing although our time here is too brief to notice
Any largely inherited series of interrelated acts, usually elicited by a particular stimulus (the releaser). Formerly called instinct
Fixed action pattern
Used to be called instincts, but this term is no longer used because it came to refer to any more or less automatic behaviour