Honors Bio Evolution study key

Briefly explain how radioactive dating works.
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Briefly explain how radioactive dating works.
Compare the amount radio active material left to the amout of stable daughter product.
If a radioactive isotope had a half-life of 1 million years, how much of it would be left after 2 million years?
25 % would be left
Radioactive dating using carbon-14 is accurate for things which are less than how many years old?
Carbon 14 dating is limited to things that are 60,000 years old or younger (after that the ratio of carbon 12 to carbon 14 becomes too small to measure)
If a fossil is made of minerals that have replaced all of the carbon in a bone, how can we tell how old a fossil is using radioactive dating?
Scientists must use a different isotope instead of carbon 14 to date the rock surrounding the fossil.
How old do scientists think the Earth is?
Current estimates for the age of the Earth is a little over 4 billion years old.
If a fossil of a bird is found in a sedimentary layer 15 meters from the surface, and a fossil of a fish is found in another separate sedimentary layer 132 meters deep, which one lived further in the past?
The fish found in the deeper layer would be older. (provided that the layers were undisturbed - law of superposition)
Describe two different kinds of fossils.
Mold - imprint of organism in rock and Cast - basically a mold filled in with rock so it is 3 dimensional
What does it mean when a fossil is found of an organism that is nothing like anything we see today?
It means that the species is extinct.
Why can't acquired traits be passed on to the next generation?
Acquired traits are the result of behavior or experience (like physical fitness or fluency in languages). They can't be passed on because they are not part of the genetic makeup of a person.
What event in Charles Darwin's life led him to form his theories on evolution?
Darwin's observations while on the HMS Beagle to many places including the Galapagos Islands led him to form his theories on evolution to help explain some of the similarities and differences he saw in the animals he encountered.
What is "descent with modification"?Descent with modification how he described animals changing (being modified) from a common ancestor like the finches on the Galapagos Islands.Who influenced Darwin's theory of "modification by natural selection"?Thomas Malthus influenced Darwin's theory of natural selection.Populations of organisms have the potential to grow in number forever. Why doesn't this happen?They are limited by food, water, access to shelter, disease etc.What drives the process of natural selection? (what makes it happen)Natural selection is driven by the environment.Briefly explain the process of natural selection.Natural selection has 4 main parts to it: A. Populations overproduce B. There is genetic variation in the population C. There is a struggle to survive either because of competition within and outside of the species or changes in the environment D. Differential reproduction - those individuals in the population that have slightly more advantageous traits will be more likely to reproduce and pass those traits on to their offspringWhich is able to adapt to their environment, individuals or populations?Populations are able to adapt to their environment (individuals are stuck with their lot in life)Which has greater fitness, very strong animal that lives for a long time but never reproduces, or a weak animal that dies immediately after reproducing?In biological terms, the weak animal that reproduces is more fit because it has passed its genes along to the next generation.What is the difference between homologous structures and analogous structures?Homologous structures are structures in different species that came from a common ancestor like the forelimbs in humans, bats and alligators. Analogous structures are structures that are similar in form like bird, bat and moth wings that evolved independently.Why are vestigial features considered to be evidence of evolution?Vestigial features are the remnants of structures no longer needed but more than likely part of the organisms anatomy in the past like a tailbone in humans and pelvic bones in whales.A lizard embryo, a frog embryo, and a human embryo, all look alike. But the frog and lizard embryos look more like each other than like the human embryo. What does this suggest?The similarities suggest that all 3 share a common ancestor but the frog and lizard are more recently related.What is the difference between convergent and divergent evolution?Convergent evolution is the process where different species develop similar traits like different species of lizards that live in twigs all have slender bodies and long tails. Divergent evolution is when descendants of a single ancestor develop different characteristics like an ancestral lizard whose descendant species may look very different (short, squat bodies vs. long slender bodies.What is the shape of a graph that shows the distribution of traits in a population?Bell CurveAre largemouth bass that live in Ford Lake in the same gene pool as largemouth bass that live in Lake St. Claire?No. Since they are physically separated they do not belong to the same population and therefore are not in the same gene pool.List three things that can cause variation in the traits of a population.1) Mutation: random change in a gene that is passed on 2) Recombination: changes that occur during independent assortment and crossing over 3) Random pairing of gametes: which sperm fertilizes which eggWhat is it called when the allele frequencies of a population stay the same over several generations?The Hardy-Weinberg genetic equilibrium: based on 5 assumptions 1. no net mutations occur 2. no immigration or emigration 3. population is large 4. individuals mate randomly 5. selection does not occur So as long as the environment does not change, the allele and genotype frequencies should not change eitherExplain the difference between gene flow and genetic drift.Gene flow is the process of genes moving from one population to another (through migration or seed dispersal). Genetic drift is the change in allele frequencies in a small population by random events or chance (like a disease breaking out).What kind of selection will occur if wolves only eat very small deer in a population that are on the small side of the bell curve?Stabilizing selection will occur and most of the population of deer will have average to larger body sizes.What kind of selection can result in speciation?Disruptive selection can lead to speciation because the individuals with either extreme variation of a trait are more fit than the average individuals.What is the difference between the morphological species concept and the biological species concept?The morphological species concept defines species based on appearance and structure. The biological species concept defines a species as a single kind of organism that can interbreed to produce fertile offspring. Each concept has limitations. Many species have a variety of phenotypes (don't look alike) but can still breed. The biological definition can't be used for extinct species so we use both ideas to define species.Give an example of geographic isolation.Geographic isolation is the physical separation of members of a population. Some examples are: drying up of a lake so that only small ponds are left, volcanic eruption where lava flows cut off parts of the population, development of a deep canyon, mountain range, new body of waterWhat is the advantage to a population of using prezygotic isolation instead of a postzygotic isolation?If a population is reproductively isolated in a prezygotic matter (premating) by means of having different mating calls or mating seasons, the females won't expend energy being pregnant with offspring that will be weak or die or sterile.Describe the two theories on the rate of speciation.The two theories on the rate of speciation (formation of new species) are gradualism and punctuated equilibrium. Gradualism says that species form slowly over a long period of time (millions of years). Punctuated equilibrium says that species form quickly (1000's of years) in response to great changes in the environment but in between species formation, species remain stable for a long period of time.A lizard embryo, a frog embryo, and a human embryo, all look alike. But the frog and lizard embryos look more like each other than like the human embryo. What does this suggest?