Bio Final flashcards

What is a chronogram?

A type of diagram (tree) that displays the timing of evolutionary events or processes and the number of lineages at those times, often using branches to show the relationships and timing of species divergence.

What is the K/T boundary?

The geological marker that signifies the extinction event that led to the demise of the dinosaurs.

What does a phylogenetic tree represent?

The evolutionary relationships among species are indicated without specific times. It illustrates the divergence and common ancestry of those species.

What is the significance of the Grande Coupure?

It was a major extinction event that allowed for modern mammalian diversification.

Give an example of adaptive radiation in mammals.

Mammals diversified after the extinction of dinosaurs due to reduced competition.

What conditions are necessary for adaptive radiation?

Ecological opportunity, reduced competition, or evolutionary innovation. These conditions allow for rapid diversification of species into new ecological niches.

What determines whether a species can occupy a niche?

Tolerance to environmental conditions and access to necessary resources.

Define 'realized niche'.

The actual conditions and space a species occupies with competitors present.

Define 'fundamental niche'.

The potential conditions and space a species could occupy without competition.

What is interference competition?

Direct interactions between species that hinder each other's access to resources.

What factors allowed Old World diseases to devastate Native Americans?

Lack of prior exposure and immunity to diseases like smallpox and measles.

What is the SIR model in epidemiology?

A model tracking individuals through Susceptible → Infected → Recovered or dead states. It helps understand disease dynamics and spread in populations.

What is rinderpest and how is it relevant to human disease?

It is a livestock disease closely related to human smallpox. Rinderpest is a viral disease affecting cattle that historically caused significant livestock mortality, impacting food security and economies, and provided insight into disease eradication strategies that can also apply to human diseases.

Why are diseases like COVID more deadly in marginalized communities?

Due to high-density living, limited healthcare access, and structural inequalities.

What is zoonotic spillover?

The transmission of diseases from animals to humans.

How did agriculture influence disease evolution?

It increased population density and contact with domesticated animals, enabling new diseases.

What is COVAX?

A global effort to ensure equitable vaccine distribution worldwide.

Why might pandemics continue in the future?

Due to continued human-animal interactions and environmental changes.

What limits our ability to predict evolution?

Unpredictable innovations and environmental changes.

How does one species split into two?

The process depends on the degree of interbreeding between populations. If interbreeding is common, speciation is less likely due to continued gene flow. If interbreeding is rare or absent, genetic differences can accumulate, potentially leading to reproductive isolation and the formation of two distinct species.

What is an evolutionary innovation?

A new trait that enables access to untapped ecological opportunities or niches. These innovations can lead to diversification and adaptation in species.

Why wouldn't rabbits evolve into deer-like forms?

Because deer already occupy that niche, leaving no ecological opportunity for rabbits to fill it. Rabbits lack the evolutionary adaptations and ecological niche needed to become deer-like.

What role does geography play in speciation?

Geographic isolation (allopatry) can prevent interbreeding and promote divergence.

What does phenotypic clustering suggest about species?

It indicates reproductive communities where interbreeding promotes cohesion.

What example illustrates limited divergence despite environmental variation?

Florida and Maine mice use different nest materials but remain the same species.

What does the diversification of birds' beaks illustrate?

Adaptation to different ecological niches through divergence.

What kind of diseases emerged during the agricultural era?

Childhood diseases that required large, settled populations to sustain transmission.

What is meant by chronic vs. acute disease transmission?

Chronic diseases persist over time, while acute diseases like measles require continuous transmission.

What prediction did Dougal Dixon make about rabbits post-human extinction?

That they might evolve into large herbivores to fill ecological voids.

How does Dougal Dixon predict rats would evolve?

Into forms occupying dog and cat ecological niches.

How do physical conditions affect species distribution?

They indirectly limit species by tipping competitive balances.

Why do some Drosophila species depend on acorns?

Because their survival is tightly linked to the availability of specific resources, like acorns.

What characterizes a permissive protein?

It has a high rate of neutral mutations and a high rate of molecular evolution.

What determines the probability of fixation of a new neutral mutation under genetic drift?

Only the population size. Genetic drift refers to the random fluctuations in allele frequencies within a population, and the probability of fixation is independent of the mutation rate or any selective advantage/disadvantage of the mutation. Furthermore, this assumes the mutation is present only once in the population.

True or False: Horizontal gene transfer can only occur between closely related organisms.

False

Why is horizontal genetic transfer less likely to result in phage resistance than antibiotic resistance?

Because phage-resistance genes are less likely to be on plasmids, are rare in distant relatives, and phages have narrow host ranges.

What is an example of ecological isolation?

Finch populations adapted to different foraging environments (trees vs. ground).

What is an example of temporal isolation?

Two populations of maple trees flowering at different times of the year.

What happens if a population exceeds its carrying capacity in the logistic growth model?

(K - N) becomes negative and the population size will decrease.

Under what conditions is exponential growth expected?

When a species colonizes a new area with abundant resources and no predators.

What are examples of interference competition?

Birds pecking to defend territory, and antelopes butting heads for mates.

Why are evergreen conifers more successful than deciduous trees in boreal forests?

Because waxy needles survive winter and allow earlier photosynthesis.

How do fossils aid in building molecular clocks?

They help calibrate the rate of divergence in evolutionary trees.

Why are fossils important for understanding adaptive radiations?

They reveal radiation (rapid diversification) in extinct groups and deep evolutionary history.