Evolution and Natural Selection Quiz

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Questions and Answers

What is the fundamental mechanism through which Darwin proposed that populations evolve over time?

Natural selection.

Explain how the concept of heritability is important to Darwin's theory of evolution.

Heritability means that certain traits can be passed from parents to offspring, which is essential for natural selection to occur.

What major flaw in Lamarck's theory of acquired characteristics was identified by later scientists?

There is no evidence to support the inheritance of acquired characteristics.

How did the work of Alfred Russel Wallace contribute to the understanding of evolution?

Wallace independently formulated a theory of evolution by natural selection, supporting Darwin's ideas. Signup and view all the answers

Describe the role of competition and resource limitation in natural selection.

Competition for limited resources results in only the most adapted individuals surviving to reproduce. Signup and view all the answers

What role do relative abundances of models and mimics play in predation rates?

A large ratio of models to mimics decreases predation, but if mimics become too common, predators learn to target them. Signup and view all the answers

List two factors, besides predator defense, that influence coloration in species.

Intraspecific sexual communication and thermoregulation. Signup and view all the answers

What is optimal foraging theory concerned with?

It examines how organisms maximize their net rate of energy gain in their foraging activities. Signup and view all the answers

Explain how prey quality affects foraging behavior.

Organisms encounter prey of unequal value, influencing their choices based on the potential energy gain from the prey encountered. Signup and view all the answers

What limitations do mimics face when relying on models for protection?

Mimics require the presence of models to gain significant protection from predators. Signup and view all the answers

How do multiple aposematic models contribute to polymorphism in mimic species?

They allow mimic species to adopt various warning signals, enhancing their survival by confusing predators. Signup and view all the answers

Why might coloration be minimal for some species that are nocturnal or subterranean?

These species may operate in environments with little or no light to reflect colors, diminishing the utility of coloration. Signup and view all the answers

What factors are considered in assessing food resource availability for foraging?

Food resources vary spatially, temporally, in quality, and in terms of accessibility. Signup and view all the answers

What does the variable 'r' represent in population growth equations and how is it calculated in this scenario?

The variable 'r' represents the intrinsic rate of population growth, calculated as the number of individuals added (R) divided by the total population size (N), which equals $16/1000 = 0.016$. Signup and view all the answers

What are the implications when r is greater than, equal to, or less than zero?

If r > 0, the population experiences exponential growth; if r = 0, the population is at equilibrium; and if r < 0, the population size decreases over time. Signup and view all the answers

Define carrying capacity (K) and explain its significance in population dynamics.

Carrying capacity (K) is the maximum population size that an environment can sustain, and it is significant because it influences growth rates based on resource availability. Signup and view all the answers

What is the logistic growth model and how does it differ from the exponential growth model?

The logistic growth model incorporates carrying capacity (K) into the growth equation, leading to a decrease in growth rate as the population approaches K, unlike the exponential model which assumes unlimited resources. Signup and view all the answers

Discuss an example of exponential growth in a species despite having a slow birth rate.

African elephants can illustrate exponential growth even with slow birth rates and late maturity due to favorable reproductive conditions in their environment. Signup and view all the answers

How do limiting factors affect the intrinsic rate of population growth (r)?

Limiting factors such as food, shelter, and water reduce the resources available to individuals, ultimately decreasing the intrinsic rate of population growth (r). Signup and view all the answers

What happens in populations when the carrying capacity is temporarily exceeded?

When the carrying capacity is temporarily exceeded, some organisms, such as certain female animals, may store food reserves to support the larger population until resources are depleted. Signup and view all the answers

Who is Thomas Malthus and what was his contribution to understanding population dynamics?

Thomas Malthus noted in 1798 that population growth is checked by limited resources, leading to struggles for subsistence which ultimately limit population size. Signup and view all the answers

What is industrial melanism, and how is it exemplified by the peppered moth?

Industrial melanism refers to the phenomenon where species evolve darker colors in response to industrial pollution. In peppered moths, the carbonaria morph (brown moth) became more common after 1850 in polluted areas, replacing the lighter typica morph. Signup and view all the answers

How does habitat influence the predation rates of the different morphs of Timema cristinae?

The grey morph of Timema cristinae faces higher predation when on plants, while the green morph has higher predation rates on the ground. This is because each morph is better camouflaged in its respective habitat. Signup and view all the answers

What are some limitations of crypsis for insects like Timema cristinae?

Limitations of crypsis include the need for selecting a proper background for concealment, which restricts insect mobility, and the requirement for secondary defenses if primary defenses fail. These factors can limit their habitat range. Signup and view all the answers

Define Müllerian mimicry and give an example.

Müllerian mimicry occurs when two or more unpalatable or harmful species evolve to resemble each other. An example includes various species of aposematic insects that share similar warning colorations. Signup and view all the answers

Explain Batesian mimicry and describe a specific example.

Batesian mimicry is when a harmless species evolves to resemble a harmful or poisonous species for protection. For example, some palatable cockroaches mimic the appearance of unpalatable beetles. Signup and view all the answers

What is Peckhamian mimicry, and how does it benefit the mimic?

Peckhamian mimicry involves a predator mimicking its prey to avoid detection. An example is a spider resembling its ant prey, allowing it to approach and capture it without alarming the prey. Signup and view all the answers

Why is crypsis more advantageous for rare species or those facing predators with poor memory?

Crypsis is more advantageous for rare species because it increases their chances of evading detection, especially if predators cannot easily learn or remember which species are harmful. This reduces predation risks. Signup and view all the answers

Discuss the role of aposematic coloration in Müllerian mimicry.

Aposematic coloration serves as a warning signal to predators, indicating that the species is unpalatable or harmful. In Müllerian mimicry, multiple species sharing this warning coloration enhance each other's survival through improved predator recognition. Signup and view all the answers

How does the nutrient status of Calluna affect the natality of grouse populations?

Higher nutrient levels in Calluna lead to increased natality in grouse populations, while overgrazing can decrease natality due to nutrient lock-up in bird bodies. Signup and view all the answers

What role does territory size play in regulating grouse populations?

Territory size influences population regulation through effects on natality and mortality, with larger territories often leading to lower breeding success. Signup and view all the answers

What are density-dependent factors (DDFs) and how do they affect grouse populations?

DDFs are biotic factors that regulate population size, such as high density leading to decreased Calluna quality and increased competition for resources. Signup and view all the answers

Explain the relationship between high grouse density and Chick mortality rates.

High grouse density can lead to lower Calluna quality, resulting in poor nutrition and higher chick mortality rates. Signup and view all the answers

What is the significance of Trichostrongylus tenius in the context of grouse populations?

Trichostrongylus tenius can spread more readily in high-density populations, potentially impacting grouse health and survival. Signup and view all the answers

How do abiotic and biotic factors interact to influence animal group living?

Abiotic and biotic factors shape environmental conditions that can compel animals to live in groups, though grouping does not always indicate social behavior. Signup and view all the answers

What distinguishes a stable population from a non-equilibrium population?

Stable populations maintain equilibrium through regulation, whereas non-equilibrium populations are unstable and subject to fluctuations. Signup and view all the answers

Why is understanding population ecology important for fields like conservation and agriculture?

Understanding population variations helps in designing conservation strategies, managing natural resources, and addressing pest control in agriculture. Signup and view all the answers

What key factor influences the attractiveness of male guppies to females in low predator environments?

In low predator environments, males are selected for bright coloration to attract females. Signup and view all the answers

How does high predator pressure affect the physical attributes of male guppies?

High predator pressure favors males with dull and smaller spots to enhance survival and ensure they can mate. Signup and view all the answers

List the three necessary conditions for evolution by natural selection.

Variation, heritability (offspring resemble parents), and a non-random relationship between phenotype and fitness. Signup and view all the answers

Define an adaptation in the context of natural selection.

An adaptation is a phenotypic variant that results in the highest fitness in a given environment. Signup and view all the answers

What observed trend did Endler discover regarding guppy spot variation in predator-rich versus predator-poor environments?

Guppy populations in predator-rich environments showed a decrease in the number of spots compared to those in predator-poor environments. Signup and view all the answers

What conclusion can be drawn from Endler's field experiments regarding local guppy populations?

Each guppy population exhibits adapted phenotypes reflective of the local balance of sexual and predation selection. Signup and view all the answers

In Endler's experiments, what unique outcome resulted from breeding guppies collected from different predator environments?

Endler created a unique population with mixed spot variations that differed from natural populations when bred together. Signup and view all the answers

How did the visibility of color to predators influence guppy coloration in environments with prawns?

In environments where prawns are the sole predators, guppies developed larger red spots because prawns cannot see red, allowing them to attract mates without risk. Signup and view all the answers

Flashcards

Theory of Evolution

The idea that organisms change over time due to natural processes acting over a long period.

Theory of Acquired Characters

Lamarck's theory (now discredited) that individuals develop advantageous traits during their lifetime and pass them on to their offspring.

Natural Selection

The process by which individuals with heritable traits that make them better suited to their environment survive and reproduce more successfully.

Darwin-Wallace Theory

Individuals within a species show variation, some of this variation is heritable, populations have the potential to grow exponentially but resources are limited, some individuals are more successful in competition, their traits are passed on.