biodiversity
Why might an ecosystem with low genetic diversity be at greater risk for extinction?
If an ecosystem is not resistant to a certain pathogen or predator, because genes aren't varied they are all vulnerable to attack and wont survive since they have no diverse adaptions that keeps species going
what are the four observations for the natural selection theory
1: All populations have
the reproductive ability to increase
in size over the generations
2: Eventually, there will
be more organisms in a population
than the available resources can
provide for
3. Within a population, most
individuals have the same traits, which
are heritable
4. These traits occur in slightly
varied forms (polymorphisms)
A population shows nonrandom mating and strong selection pressure from a new parasite. is this in hardy weinberg equilibrium why or why not
The population is not in Hardy–Weinberg equilibrium because multiple assumptions are violated.
Two bird species perform different courtship dances and refuse to mate. Explain what type of isolation this and what kind of barrier
Behavioral isolation, a prezygotic barrier.
Why can radiocarbon dating NOT be used for dinosaur fossils?
Carbon-14 only works for about 50,000 years, while dinosaurs lived millions of years ago.
there is a jungle filled with trees, monkeys, rivers, fungi, shade since the trees block the sun. List the abiotic factors
river, shade (sunlight blocked)
t/f natural selection can act on genotypes
false - acts on phenotypes
Brightly colored male fish attract mates but are eaten more often by predators. what does this display
Sexual selection favors reproduction, while natural selection favors survival, creating evolutionary tension.
A mountain range splits a population, and speciation follows. Why is this common?
Geographic barriers stop gene flow, allowing populations to evolve independently (allopatric speciation).
Why do mass extinctions often lead to bursts of evolutionary innovation?
Extinctions open ecological niches, reducing competition and allowing surviving groups to diversify (adaptive radiation).
A lake becomes contaminated with mercury. Explain why birds that eat fish from the lake are more affected than the fish themselves.
Birds that eat contaminated fish are more affected because mercury biomagnifies up the food chain. As each predator consumes multiple contaminated prey, the toxin concentration increases, leading to the highest levels in top predators.
what type of natural selection does this demonstrate: In ancient humans, very small men might not be very attractive to women because they can't defend their family as well but large men might have a more difficult time finding enough food. Very large men would tend to be slower and have less endurance.
stabilizing - doesnt favor either extremes
Penguins have wings structured like other birds but cannot fly. Cave fish possess nonfunctional eyes. Explain how each one of these are evidence to evolution and why?
Penguins - Homologous structures, indicating shared ancestry despite different functions.
cave fish - Vestigial structures, evidence that ancestors once relied on vision.
When species re-contact, three outcomes are possible:
Reinforcement: stronger reproductive barriers
Fusion: populations merge
Stability: hybrids continue forming
Why is radiometric dating considered more reliable than relative dating?
It provides an absolute numerical age, whereas relative dating only determines whether something is older or younger.
latitude / wind ocean currents; A monsoon is a seasonal shift in wind direction that brings periods of heavy rain and dry weather.
After a hurricane wipes out most of a beetle population, the surviving beetles are mostly green instead of brown purely by chance. what is this an example of
bottleneck effec
Explain why evolution is not goal-directed using antibiotic resistance as an example.
Mutations occur randomly; bacteria did not evolve resistance “on purpose.” The environment simply favored resistant individuals.
Put the protocell stages in logical order and explain why membranes were critical:
Abiotic synthesis of organic molecules
Polymer formation
Membrane formation
Self-replicating molecules
Membranes allowed separation from the environment — a key step toward true cellular life.
During which era did life diversify rapidly in the oceans in an event sometimes called an evolutionary “explosion”? Why was it significant?
The Paleozoic Era (Cambrian Explosion). Most major animal body plans appeared, shaping future evolution.
what biome is characterized by rainy and cold season around 50-70 N of equator
coniferous forest/ temperate rainforest
A few birds colonize a remote island, and generations later the population shows very different allele frequencies than the mainland population.
what is this an example of
founder effect
DKPCOFGS is hierarchical. If two organisms share the same genus but different species, what can you infer?
They are closely related and share a recent common ancestor.
Why do redshift and CMB together provide stronger evidence than either alone?
Redshift shows expansion, while CMB confirms an early high-energy origin. Together they independently support the Big Bang.
Early Earth (Precambrian time) was dominated by microbial life. What does this reveal about evolution?
Simple organisms can thrive for billions of years; complexity is not required for evolutionary success.