Trophy Hunting and Evolutionary Biology

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Questions and Answers

What is the primary motivation behind trophy hunting?

To rehabilitate vulnerable species

To promote biodiversity in ecosystems

To seek the largest and oldest animals (correct)

To increase food supplies for local communities

How does trophy hunting impact conservation funding?

It serves as a major source of funding for conservation efforts (correct)

It promotes illegal hunting practices

It decreases the amount of funds available for conservation

It only benefits large corporations rather than local communities

What significant change in elephant tusk size was observed between 1960 and 2013?

Decline in tusk size attributed to selective poaching (correct)

Increase in tusk size due to genetic modifications

No change in tusk size over the decades

Increase in tusk size due to conservation efforts

What is true about the alleles in genetics?

Alleles can coexist within the same organism Signup and view all the answers

What encompasses the concept of evolution?

Changes in allele frequency over time Signup and view all the answers

How does selective poaching affect the population dynamics of elephants?

It negatively impacts the average size of tusks Signup and view all the answers

What was one of the key objectives of Community Based Natural Resource Management (CBNRM) in Botswana?

To provide income while conserving resources Signup and view all the answers

What factor contributes to the evolution of organisms as stated in the content?

Natural selection, genetic drift, and gene flow Signup and view all the answers

What is meant by recombinations in the context of offspring?

Offspring with different combinations of alleles from both parents Signup and view all the answers

What is the primary mechanism of evolution described by Charles Darwin?

Natural selection Signup and view all the answers

What does 'descent with modification' imply in Darwin's theory?

Populations become distinct over time through inherited traits Signup and view all the answers

What role does fitness play in natural selection?

It measures an individual’s ability to survive and reproduce Signup and view all the answers

What outcome does natural selection not result in?

Individual organisms evolving within their lifetime Signup and view all the answers

What is one of the major goals of genetically modified organisms (GMOs)?

Pest protection Signup and view all the answers

Which crops account for approximately 95% of soybean and cotton acres in U.S. agriculture?

Herbicide-tolerant and Bt-transgenic crops Signup and view all the answers

What has been the effect of using herbicide-tolerant (HT) and Bt crops over the first six years of commercial use?

Reduced pesticide use by 31 million pounds Signup and view all the answers

How does genetic drift primarily affect populations?

By randomly determining allele transmission Signup and view all the answers

In which scenario is genetic drift most likely to have a significant effect?

Small populations Signup and view all the answers

What can be a consequence of genetic drift in small populations?

Disappearance of certain alleles Signup and view all the answers

What best describes gene flow?

Transfer of alleles between populations through gametes or individuals Signup and view all the answers

What is true regarding GMO regulation in the US?

GMO foods are subject to rigorous regulation. Signup and view all the answers

What is speciation?

The process by which one species splits into two or more species. Signup and view all the answers

What typically leads to speciation?

Barriers that prevent gene flow. Signup and view all the answers

How long did it take for multicellular life to evolve in the history of life on Earth?

50 seconds Signup and view all the answers

What defines a mass extinction event?

A large proportion of species going extinct in a short time. Signup and view all the answers

What is the current status of the 6th mass extinction?

It is primarily caused by human activity. Signup and view all the answers

What is an evolutionary tree?

A graphical representation of evolutionary relationships. Signup and view all the answers

Which species group experienced the largest loss during the 6th mass extinction?

Amphibians Signup and view all the answers

What is required for speciation to occur between new species?

A reproductive barrier must develop. Signup and view all the answers

What characteristic of beak depth in Darwin's finches was noted after the drought in 1977?

Beak depth decreased in the next generation Signup and view all the answers

Which type of natural selection favors individuals with intermediate phenotypes?

Stabilizing selection Signup and view all the answers

What was the key factor that allowed finches with deep beaks to survive during the drought on Daphne Major?

Ability to consume harder seeds Signup and view all the answers

How can evolution be described in the context of environmental changes relating to finch beak depth?

It can be rapid and context-dependent Signup and view all the answers

What is an example of directional selection as discussed in the case study?

Bacteria developing antibiotic resistance Signup and view all the answers

What happens to the beak depth of Darwin's finches after prolonged wet conditions following a drought?

It decreases due to preference for soft seeds Signup and view all the answers

What signifies disruptive selection in a population?

Both extreme phenotypes are favored Signup and view all the answers

Which statement best articulates the nature of heritable traits in finches?

Heritable traits can gain or lose prominence based on environmental factors Signup and view all the answers

Which condition describes the normal distribution of beak depth in the medium ground finch?

Beak depth varies consistently across the population Signup and view all the answers

In the case of Darwin's finches, what effect did the extreme drought have on the finch population?

It resulted in high mortality, favoring deep beak survivors Signup and view all the answers

Study Notes

Trophy Hunting

Trophy hunting targets the oldest, most mature animal from a population.
It provides income for residents of the land.
Ecotourism alleviates poverty and supports conservation.
Trophy hunting is historically a big funder of conservation.

The Evolutionary Impact of Trophy Hunting

Hunting and fishing regulations can target older, larger males; which reduces their ability to sire large numbers of offspring.
Selective poaching caused a dramatic decline in elephant tusk size in two generations.
Despite tusk size decreasing, shoulder height increased.

Natural Selection

Darwin proposed populations change through "descent with modification" which occurs through natural selection.
Natural selection favors individuals who leave more offspring and have improved fitness.
Evolution is gene frequency change over time.
Recombinations are offspring that have a different allele combination than either parent.

Darwin's Theory of Evolution

Darwin worked on the HMS Beagle from 1831-1836, and published The Origin of Species by Means of Natural Selection in 1859.
Darwin's theories were similar to Alfred Russel Wallace's.
Darwin's theory of evolution notes that species become different over time through natural selection.
Organisms have modifications that improve their fit for their environment.

Natural Selection in Populations

Natural selection can cause populations to diverge over time.
Populations, not individuals, evolve.

Case Study: Beak Morphology in Galapagos Finches

Darwin's Finches on Daphne Major have beak depths that follow a normal distribution.
Beak depth is a heritable trait.
Daphne Major has significant climate variability.
During an extreme drought, finches with deep beaks survived better because they could access harder seeds that remained available.
In wet years, beak depth decreased as soft seeds were easier to access.
This example demonstrates that the same trait can be advantageous in one environment and disadvantageus in another.

Types of Natural Selection

Directional selection favors individuals with one extreme trait.
Stabilizing selection favors individuals with intermediate traits.
Disruptive selection favors individuals with extreme traits on both ends of the spectrum.

Antibiotic Resistance

Antibiotic resistance can be viewed as directional selection.
Mycobacterium tuberculosis has a gene that can prevent rifampicin (an antibiotic) from being effective.

Selective Breeding

Historic selective breeding techniques were used to intentionally breed animals with desirable traits- such as breeding dairy cattle with higher milk production.

GMOs

GMOs (Genetically modified organisms) have major goals of pest protection, herbicide resistance, and drought tolerance.
In the US, GMO foods are regulated to the same standard as non-GMO foods, but they do not have to be labeled in the US.
No proven ill effects have been reported in humans from consuming GMOs.
Herbicide tolerant and Bt-transgenic crops dominate US agriculture.

Mechanisms of Evolution: Genetic Drift

Genetic drift is a random process that affects small populations, causing unpredictable changes in allele frequency.
Genetic drift can lead to the loss of alleles in a population.

Mechanisms of Evolution: Gene Flow

Gene flow occurs when alleles transfer between populations through the movement of individuals or gametes.

Long-Term Consequences of Evolution

Speciation, mass extinction, and adaptive radiation shape long-term patterns of evolution.
Speciation is the process by which one species splits into two or more species.
Speciation often occurs due to geographic or ecological barriers that prevent gene flow.

Speciation

Speciation results in a reproductive barrier between the new species.

Mass Extinction

A mass extinction event occurs when a large proportion of species worldwide go extinct in a short timeframe.
Mass extinction events have occurred throughout history, with each one leading to changes in dominant species on Earth.
For example, amphibians were replaced by reptiles as the dominant terrestrial vertebrates 265 million years ago, and reptiles were replaced by mammals 65 million years ago.

Sixth Mass Extinction

Evidence suggests a sixth mass extinction may be occurring due to human activities; with many species disappearing at an accelerated rate compared to typical extinction rates.
Amphibians are particularly vulnerable to this sixth mass extinction.

The Evolutionary History of Life

Evolutionary trees represent the evolutionary history of a group, showing branching patterns of speciation and extinction.
Evolutionary trees show the increase of species through speciation events, and the loss of species through extinction.

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Description

Explore the intricacies of trophy hunting and its evolutionary implications. This quiz covers the economic aspects of hunting, its impact on animal populations, and how natural selection shapes species over time. Delve into Darwin's theories and the consequences of selective pressures on wildlife.