Exam 1: Lecture 4 Flashcards
What chromosome is structurally similar between males and females?
the X chromosome the y is more complex and different
What percentage of genes are the same across humans, and what percentage is different?
Around 0.5% of genes differ within humans, while 99.5% of genes are the same across individuals.
How many chromosomes do gametes have?
Gametes contain half the number of chromosomes, specifically 23 unpaired chromosomes in each sperm or egg
How many chromosome combinations are possible in gametes?
There are 2^23 possible combinations of chromosomes in gametes, leading to genetic diversity. This variation in gametes contributes to the genetic uniqueness of offspring
How do cells determine their function?
all cells have the same genes but they specialize based on which genes are active
what is the central dogma?
describes how DNA is transcribed into RNA, which is then translated into proteins.
What performs most biological functions?
proteins and the variation in proteins is largely determined by which genes are expressed in specific cells
How many chromosomes do chimps have?
48 chromosomes (24 pairs) this is due to how they are organized
Why do humans have 46 chromosomes and not 48 like our great ape ancestors?
Some chromosomes in great apes have fused in humans, leading to the reduction from 48 to 46 chromosomes. Each end contains a telomere, and one in the middle of the chromosome indicating 2 were fused
what is a telomere?
Each chromosome has telomeres at its ends, which protect the DNA from unraveling or fraying. this is common across species and serves to maintain DNA integrity
what are alleles and how many do humans have?
different forms of a gene located at a particular locus on a chromosome. Humans typically have two alleles for each gene (one from each parent), but some loci may have multiple alleles, contributing to genetic variation. This variation is responsible for individual differences and population diversity.
how much of our genes are shared with chimpanzees?
98.5% (4x as great as the differences between humans)
What are 3 ways genetic diversity is introduced?
migration, sexual recombination, and gene flow from immigration
Does genetic diversity continuously increase?
no
does selection reduce or increase the variety of genes?
selection reduces the variety of genes
How do alleles become more common?
Selection leads to the spread of beneficial genes within a population, making certain alleles more common.
What is a fixed gene?
If an allele becomes present in all individuals in a population, it is no longer considered an allele but rather a fixed gene
penetrance
how widely a particular allele is expressed across the population.
what percentage of genes do humans share with rats?
90%
Why are we so different from other species despite genetic overlap?
Even with such high genetic overlap, the expression of genes (which genes are turned on or off) plays a major role in the distinct characteristics of species (appearance, behavior, and physiological traits).
Which has a greater role, nature or nurture?
they both have the same effect, 100%
Is there more evidence that humans are biologically special or more against it?
more against it. The charles darwin theory that humans were not vastly different from other species this upset many people
what makes humans “unique”? Name 7 things
- bible
- have a mind/soul independent of the brain
- unique body
- tool use
- intellect
- language
How did Darwin view conflict with religious teachings?
in the context of creationism (humans created on a different day), it was one of the earliest arguments, Many religions also believe a soul survives biological death, although science has never proven that
What other animals use tools and what do they use them for?
chimps use branches to collect termites, long-tailed macaques use stones to break open shells, whales use air bubbles to corral fish, sand wasps use fragments of mollusk shells to create nests, and polar bears use rocks to hunt, especially when hunting walruses, Caledonian crows use twigs to get insects; they save their tools to reuse and keep the ones that took more effort, showing they understand the value of effort invested.
New Caledonian crows have high behavioral plasticity. What does that mean?
remarkable problem-solving skills
how do monkeys make sex toys? what does this tell us about tools?
use stones as tools for sexual stimulation (this shows tools can have non-survival uses)
What is the definition of a tool?
A tool is any object that helps manipulate the environment to achieve a goal, such as obtaining food.
what is reflexive behavior?
Reflexive behavior, where actions are driven by instinct without conscious reflection (all nonhuman species are assumed to have this)
What is control processing?
when a species is capable of conscious thought and control over their actions (it was assumed that only humans have this)
Are nonhuman species smarter than we previously thought?
Yes, they show evidence of complex thought and problem-solving abilities, and we as humans may not be as intellectually advanced as one assumed. We may share more intellectual abilities than we originally thought
is human behavior influenced by actions without awareness?
yes many actions become automatic and this develops early in life making it second nature ex: we walk without conscious thought
Do our minds link experiences to certain objects or events?
Yes, e.g., a researcher ate a steak with sauce, so did his colleagues, but they didn’t get sick. Years later, he still cant look at the sauce without his stomach turning; his brain linked the sauce to his sickness
is there a mismatch between introspection and actual behavior?
yes ex: Tiger Woods was asked about his golf swing and his description didnt fully match his actions, Woods thought he was providing an accurate report but his muscle memory took over, showing a disconnect between introspection and actual behavior
neural pathways
Information can be processed through neurons in the spinal cord without conscious awareness reaching the brain.
learning seen in cats with spinal injuries
Cats with spinal injuries still exhibit learning behaviors, like withdrawing their foot in response to painful stimuli, even though the brain is not involved.
What are Aplysia (sea slugs) and sea peligence (tiny wormlike creatures) useful for?
Aplysia has large neurons, making it easier to study how learning works in animals with simpler nervous systems.
Sea Peligence: Despite its tiny brain with only 200 neurons, it can still learn, and that learning mechanisms is widespread across species
Do species have different intellects?
Yes: each species has a different level of intellect, but it’s unclear if human intellect is vastly superior compared to other species.
Why cant apes talk like us?
Apes have higher vocal cords compared to humans, which limits their ability to produce human-like speech.
Despite this, they can learn simple signs in American Sign Language.
the ape experiment
An experiment by a couple at the University of Nevada raised a chimpanzee alongside their child to observe language development.
The child developed normally, but the chimpanzee began imitating sounds but didn’t develop full language.
what sounds do chimps make to warn about predators or about food?
one sound is for predators that can climb trees; another is for those that cannot. also when food is found and what food
Can chimps develop an understanding of syntax?
to some degree but not the level of complexity seen in humans
What did the chimps Vicki, Washoe, Sara, and Nim Chimpsky learn?
Vicki—oral speech
Washoe—American Sign Language
Sara—magnetized plastic shapes
Nim Chimpsky—symbols on keyboard
Alex the parrot
Alex couldn’t fully speak like humans, he demonstrated the ability to use words and understand simple syntax.
Alex’s researcher dedicated 30 years to teaching him language-like communication, and Alex could recognize objects, express feelings, and engage in simple conversations.
Alex got his own obituary in the New York Times
dogs and vocab learning (chaser)
Chaser, a boarder collie learned over a thousand object names and was able to identify them when asked. (this shows vocabulary learning
a gene that produces our speech is also found in what other species?
Birds this suggested a genetic link in communication. Mice performed tasks with shapes with the same gene. This suggested a genetic link for learning and communication that is fundamentally similar across different animal species
