Evolution and Natural Selection

These flashcards cover key concepts from the lecture on evolution and natural selection, providing a comprehensive review for the exam.

What is evolution?

Evolution is defined as 'descent with modification' and the change in characteristics of populations over time.

What central mechanism drives evolution?

Natural Selection is the central mechanism of evolution whereby organisms better adapted to their environment survive and reproduce.

Define Natural Selection.

Natural selection is the evolutionary process where individuals with certain heritable traits are more likely to survive and reproduce.

What concept explains population changes over time?

Evolution focuses on how allele frequencies change over time.

Name the three key observations Darwin based his theory of natural selection on.

1) Overreproduction 2) Individual Variation 3) Genetic Variation.

What is meant by 'fitness' in evolutionary terms?

Fitness describes an individual's reproductive success; an organism has higher fitness if it leaves more offspring that survive to reproduce.

What is adaptive radiation?

Adaptive radiation is the evolution of a group of organisms into a wide variety of types adapted to specialized modes of life.

How does natural selection relate to survival?

Natural selection weeds out individuals that are unfit in a particular environment.

What is artificial selection?

Artificial selection is causing evolutionary change by human choice, such as selective breeding.

What role do mutations play in evolution?

Mutations are random changes in the DNA that introduce genetic variation, serving as the ultimate source of genetic diversity.

What is the difference between microevolution and macroevolution?

Microevolution refers to small genetic changes within populations, while macroevolution describes larger evolutionary changes observed in species over time.

What evidence supports the theory of evolution?

Evidence includes fossil records, biogeography, and homologous structures among diverse species.

Who was Thomas Malthus and how did he influence Darwin?

Thomas Malthus wrote about population growth and competition for resources, influencing Darwin's ideas on natural selection.

What is genetic variation and why is it important?

Genetic variation refers to differences in DNA among individuals within a population, which is crucial for natural selection.

What are vestigial structures?

Vestigial structures are remnants of organs or structures that had a function in early ancestors but are now reduced or nonfunctional.

What is the significance of Darwin's Beagle voyage?

Darwin's voyage allowed him to observe variations in species and gather evidence that contributed to his theory of natural selection.

What does 'descent with modification' mean?

Descent with modification refers to the principle that each generation of organisms is different from its ancestors.

How does competition influence natural selection?

Competition for limited resources leads to a struggle for existence, where only the fittest individuals survive.

What is the role of environments in natural selection?

Environments act as agents of selection, influencing which traits are advantageous for survival and reproduction.

How can evolutionary change occur rapidly?

Evolution can happen in a few generations, particularly in response to strong selective pressures.

What is the importance of allele frequency in evolution?

Changes in allele frequency within a population over time indicate the process of evolution.

How did Darwin explain similarities among species?

Darwin proposed that similarities among species arise from common ancestry shared by these organisms.

What is the impact of global warming on species?

Global warming affects breeding times and behaviors of many animal species due to environmental changes.

How does sexual selection differ from natural selection?

Sexual selection is a mechanism of evolution related specifically to mate choice and reproduction rather than survival.

What is the modern synthesis in evolutionary biology?

The modern synthesis is the integration of genetics with Darwin's principles of evolution.

What are experimental evolution studies?

Experimental evolution studies allow scientists to observe evolutionary changes in controlled lab settings.

What is the difference between homologous and analogous structures?

Homologous structures share a common ancestry while analogous structures perform similar functions but do not share a common ancestry.

What does the term 'struggle for existence' refer to?

It refers to the competition between organisms for limited resources necessary for survival and reproduction.

How did Darwin contribute to the understanding of biogeography?

Darwin studied the geographic distribution of species, leading to insights about how species evolve in isolation.

What is the significance of allele recombination during sexual reproduction?

Allele recombination introduces new genetic variations that can influence evolutionary outcomes.