Evolution Flashcards
Define evolution
The process in which significant changes in the inherited traits (the genetic makeup) of a species occurs over time
Based on astronomy, history, and biblical study, who declared the Earth was created on Sunday, October 23, 4004 BC?
Archbishop James Ussher
Define fossil
Any preserved remains or traces of an organism or its activity
Who found numerous seashell fossils high in the Tuscan mountains and concluded that the remains must have been from an ancient ocean?
Leonardo da Vinci
Which period in history marked a time of increased awareness of evolutionary biology?
Mid 1700s
Who was the first scientist to recognize that evolution of species were influenced by environmental factors?
Jean Baptiste Lamarck
Who was the grandfather of Charles Darwin, heavily involved in his first ideas of evolution?
Erasmus Darwin
Who postulated the Principle of Population in 1798, which influenced Charles Darwin?
Thomas Malthus
What does Malthus’ Principle of Population describe?
That the preservation of a species depended on availability of resources such as food
Which two scientists worked together on the Punctuated Equilibrium theory, published in 1972?
Stephen Jay Gould and Niles Eldredge
Describe Gould and Eldredge’s Punctuated Equilibrium
Long periods of stability in a population punctuated with branches of rapid evolutionary change
In which year did Darwin embark on the HMS Beagle?
1831
What was the primary purpose of the HMS Beagle’s voyage?
To survey and map the coastal waters of South America for the British
What was Darwin’s intended role on board the HMS Beagle?
To collect specimens of rocks, minerals, plants, and animals to find evidence supporting biblical creation
Which animal did Darwin study that was the key to biogeography?
Finch
What observation did Darwin make about finches on the Galapagos Islands?
They had adapted their beaks according to which type of food was found on the island on which they lived
Define homologous feature
Structures that share a common origin but may serve different functions in modern species
What is an example of homologous features and what makes them so?
Seal flippers and human arms are similar in bone structure but they carry out different functions
Define analogous features
Structures that are similar in function but not in origin or anatomical structure
What is an example of analogous features and what makes them so?
Wings of birds and insects. They share similar functions but have a different internal anatomy
Define vestigial features
Structures that serve no useful function in living organisms
Give two examples of vestigial features
Pelvic bones in whales, appendixes in humans
What does the pelvic bone indicate in whales?
That they evolved from ancestors that had legs
What happens to species that cannot adapt to their surroundings?
They become extinct
What factors determine the survival of a species?
Variation, how organisms interact with their environment, being able to reproduce and pass along traits to their offspring
Define adaptation
A structure, behaviour, or physiological process that helps an organism survive and reproduce
Give an example of adaptation in appearance
Stick bug
Give an example of physiological adaptation
Hibernation
Why is hibernation an example of physiological adaptation?
It allows animals to survive in harsh climates, reducing a species’ metabolism to save energy
Give two examples of animals that hibernate
Squirrels, bears
What are the four types of adaptation?
Structural, behavioural, physiological, mimicry (special type of structural)
Give an example of structural adaptation
The needle-sharp talons and excellent vision of owls makes them a good predator in their environment
Define mimicry
A special type of structural adaptation in which many harmless species resemble a harmful species colouration and structure
Give an example of mimicry
The viceroy butterfly which is edible mimics the monarch butterfly which is inedible
What are the result of gradual, accumulative changes that help an organism reproduce and survive?
Adaptations
What are structural, functional, or physiological differences between individuals?
Variations
What determines if a variation has a positive, negative, or no effect?
Environmental conditions
Describe how positive variation affects an organism
It will increase the survival and reproduction of that individual and thus, help them pass on their variation to their offspring. In time, this variation will be the norm and become considered a trait
Define variation
Any difference between individuals of the same species. These are inherited traits that make an individual different from the others
Define adaptation
Any trait that helps an organism survive and reproduce
In what ways can species show variation?
Genetically and environmentally
Give an example of environmental variation
Industrial Melanism
Define industrial melanism
The adaptation of a population in response to pollution
Describe how the peppered moth adapted to the changing landscape of England in the 1800s
During the time of the Industrial Revolution, the lush green countryside was transformed by factories into polluted environments. The peppered moth blended into the white trees, keeping them safe from predators. When pollution caused the tree bark to blacken, the moths evolved to be black, while the white moths died
Describe how variation happens
Arises due to differences in the genes. Through sexual reproduction, the number of possible combinations results in genetic variation. Mutations that occur in the gametes are what get inherited and are thus the starting point of genetic variation
What are the genetic variations that we can see?
Phenotypes
What are the genetic variations that have no visible effect?
Genotypes
Define mutation
Changes in the DNA of an organism that provide new alleles in a species
How do mutations occur?
Can occur spontaneously during the S phase of interphase or through mutagens (UV, environmental agents, etc.)
Are all mutagens harmful?
Some can be harmful, some can be silent (neutral), and others can be beneficial
Define selective advantage
A genetic advantage of one organism over its competitors. It will cause an organism to be favoured in terms of survival and reproduction
Give an example of selective advantage
Daphnia with a mutation that enables it to survive in temperatures between 25 and 30°C can live in the warming waters while others without this mutation will die
What species benefit the most from selective advantage?
Rapidly reproducing species
Give an example of rapid reproduction providing selective advantage
Antibiotic resistance: certain strains of bacteria have a new allele that make them resistant. Because they reproduce so quickly, the next generation has a greater chance of survival
Describe natural selection
The process of change in the characteristics of a population over many generations
Why does natural selection occur?
Individuals with certain inherited traits survive specific local environmental conditions and, through reproduction, pass their alleles on to their offspring
What term describes an organism that produces offspring that also survive to reproduce
Fit for the environment
Under which circumstance can natural selection only occur?
If there is genetic diversity within a population. That diversity arises from random mutations accumulating in the population
Describe selective pressure
When an environmental condition selects for or against certain characteristics in some individuals
Temperature change, light level change, change in predators, and change in competition are all example of what?
Selective pressure
Give an example of selective pressure
A dense tree population with little sunlight reaching the floor in a forest. This favours organisms able to survive in low light levels
Define artificial selection
A selective pressure exerted by humans on a population in order to improve or modify particular traits
Although practiced for thousands of years, why is artificial selection considered a form of biotechnology?
It uses organisms to produce useful products
Give examples of artificial selection
Cats bred for appearance, cows bred to increase muscle for meat consumption, chickens bred to produce more eggs
Give an agricultural example of artificial selection
The wild mustard plant can be developed into many different crops, such as kohlrabi, kale, broccoli, brussel sprouts, cabbage, and cauliflower
Give a general and specific example of a consequence of artificial selection
It often decreases the genetic diversity of a population, which makes it less fit for environmental changes and natural selection. English bulldogs are bred to have flat faces, but as a result, many suffer from respiratory problems
Where is artificial selection commonly used in agriculture?
In monocultural planting, where a large area has one type of plant with little genetic diversity
What are the consequences of monoculture in agriculture?
Although it is easier to manage, there is high risk that environmental change such as a new disease could wipe out the crop
Describe the importance of gene banks
They include seeds from early, wild versions of plants that still include the genetic diversity our modern crops have lost
Who was one of the first scientists to carry out empirical studies on the natural world?
John Ray
Who developed a classification system for plants and animals based on anatomy and physiology, that were refined by Linnaeus?
John Ray
Who was one of the first people to publicly challenge the idea that life forms are unchanging?
Georges-Louis Leclerc, Comte de Buffon
Who noted the similarities between humans and apes and speculated that we came from a common ancestor, suggesting species change over time?
Georges-Louis Leclerc, Comte de Buffon
Who worked as a fossil hunter and uncovered the first plesiosaur (aquatic reptile)?
Mary Anning
Whose work was confirmed by Georges Cuvier, the founder of palaeontology?
Mary Anning
Define palaeontology
The study of ancient life through the examination of fossils
What evidence was provided by Cuvier that species could become extinct?
He found that each stratum (layer of rock) had their own unique fossil species and that the deeper the stratum, the more different the life was from modern form. As he worked from stratum to stratum he found evidence of new species as others disappeared
Define catastrophism
The theory that catastrophes killed many species and that these events corresponded to the boundaries between the fossil strata
Which theory rejected Cuvier’s theory of catastrophism?
Uniformitarianism
Describe uniformitarianism
Geological processes in the past operate at the same rate as they do today, suggesting that a slow and continuous process could result in substantial changes in the long term
Who proposed the theory of catastrophism?
Georges Cuvier
Who proposed the theory of uniformitarianism?
Charles Lyell
How old was the Earth as agreed upon by Lyell and Cuvier?
6000 years old
Who proposed a “line of descent” progression between current species and fossil forms?
Jean-Baptiste Lamarck
Describe the line of descent theory
Species increased in complexity and became better adapted to their environment over time
What is the term which describes how traits developed during an organism’s life could be passed on to offspring?
Inheritance of acquired characteristics
Which economist wrote the Essay on the Principles of Population that explained how populations might change over time?
Thomas Malthus
What was the key idea of Malthus’ Essay on the Principles of Population?
Populations produce far more offspring than their environments can support
What theory did Darwin propose based on observations of the coast of South America?
Theory of natural selection
Describe the theory of natural selection
Life has changed and continues to change, due to natural pressures (refer to other cards on natural selection)
Who made observations and conclusions similar to Darwin, and recognized the importance of Malthus’ essay?
Alfred Russel Wallace
Describe the idea of “survival of the fittest”
Organisms can produce more offspring than can survive, therefore organisms share limited resources. Individuals of a population vary extensively, and those better suited to the environment produce more offspring
What is the term for how quickly evolution occurs?
Descent with modification because the change does not demonstrate progress (improvement), it is simply change with no set direction
What observations did Darwin make that led to his theory?
The flora and fauna were different in different regions. He found fossils of extinct animals that looked similar to living animals. He also found that finches resembled each other but were different in some characteristics, adapted to the food source on each island
What are the main sources of evidence for evolution?
Fossil evidence, biogeography, anatomy, embryology, DNA
How can we determine the age of an organism through fossils?
The deeper the layer of rock stratum, the older the organism, showing the successive evolution of groups of species
What is the study of the past and present geographical distribution of organisms?
Biogeography
What hypothesis did Darwin and Wallace make with respect to biogeography?
Species evolve in one location and then spread to others
Give four examples to support biogeography
Geographically close environments are more likely to be populated by related species, animals found on islands often closely resemble animals on the nearest continent, fossils of the same species can be found on the coastlines of neighbouring continents, closely related species are almost never found in exactly the same area
What is the study of pre-birth stages of an organism’s development?
Embryology
What is common among all vertebrate embryos?
Have paired pouches or out-pocketings of the throat that later develop into ears/throat or gills
What is common among related species embryologically?
Share common embryological stages and timings of structural development
Describe evidence from DNA
Species that have similar DNA have a common ancestor
