BIO FINAL EXAM Flashcards
(25 cards)
What factors influenced Darwin as he synthesized the theory of evolution by natural selection?
Observations during voyage on HMS Beagle & artificial selection by humans
How would you best measure an organism’s fitness?
reproductive success / # of viable offspring it leaves in the next generation.
How is genetic variation preserved in populations?
Diploidy, balancing selection (ex: heterozygote advantage), frequency-dependent selection, and neutral mutations
How can a detrimental allele remain in a population?
Recessive & hidden in heterozygotes / Heterozygotes have an advantage (like with sickle cell and malaria) / Helps in a certain environment
In a population with two alleles, B and b, where b = 0.5, what is the frequency of individuals with the homozygous dominant genotype under Hardy-Weinberg equilibrium?
p = 0.5 (B) → Homozygous dominant = p² = 0.25 or 25%.
How does antibiotic and antiviral resistance relate to natural selection?
Resistant microbes survive the drugs, reproduce, and pass on resistance
What are the characteristics of different species concepts?
Biological - Reproductive isolation / Morphological - structural features / Ecological - Niche / Phylogenetic - shared ancestry
Characteristics of Prezygotic reproductive barriers?
Habitat / temporal / behavioral / mechanical / gametic isolation
Characteristics of Postzygotic barriers?
Reduced hybrid inviability / Reduced Hybrid Fertility / Hybrid breakdown
What is adaptive radiation? Example?
Rapid diversification of species into many new forms, especially when new habitats/niches are available. / Darwin’s finches.
A new plant species (C) forms by hybridizing species A (2n=20) and B (2n=16). What is the chromosome number in gametes of species C?
18 chromosomes.
What can happen in hybrid zones?
Reinforcement - of reproductive barriers / Fusion - of species / Stability (continued hybrid production)
What factors contribute to allopatric speciation?
Geographic isolation, genetic drift, natural selection, and time.
Why are India’s plants and animals different from nearby Southeast Asia?
India was once a separate landmass and collided with Asia later, leading to independent evolution of species.
Why were ancient photosynthetic prokaryotes important?
Released oxygen into the atmosphere, enabling aerobic respiration & evolution of complex life.
The evolution of the swim bladder from lungs is an example of what?
Exaptation - where a structure evolves for one function & co-opted for another.
How would you choose an outgroup for your ingroup in a phylogenetic tree?
Choose a species that is closely related to, but not part of, the ingroup to help determine ancestral vs. derived traits
What provides the best data for determining the phylogeny of very closely related species?
Comparison of DNA sequences
What causes changes in the seasons?
Tilt of Earth’s axis as it orbits the Sun.
What are the characteristics of a desert biome?
Low precipitation, extreme temp variation, sparse vegetation, & adapted organisms.
Which sea creatures are pelagic vs. benthic?
Pelagic - live in open water (e.g., tuna, jellyfish) / Benthic - live on the sea floor (e.g., crabs, sea stars)
Where do phytoplankton reside?
In the photic (sunlit) zone of aquatic environments where photosynthesis can occur.
What are the levels of ecology?
Organism → Population → Community → Ecosystem → Biome → Biosphere
What is social learning?
Learning behaviors by observing others, often seen in animals/humans.
