ACC BIO life on earth exam 2 study guide
What two things did Darwin infer from his observations?
1) The individuals who inherited a set of characteristics that best allowed them to survive in their environment were the ones who had more offspring (this is called differential reproductive success) 2) Because those offspring will make up a larger proportion of the next generation, their traits will become more common in the next generation.
What are the two conditions required for evolution in a population?
1) There must be genetic variation. 2) There must be pressure from the environment that favors one combination of DNA over others.
In the scenario in the SW United States, lava replaced the normal sandy habitat for the pocket mouse with a black environment. A mutation for a black mouse (a founding mutation) occurred. If the advantage of being a black mouse on black lava is 1%, how many generations did it take for 95% of the mice to be black in color?
1,000
impression fossil
A shallow imprint, such as dinosaur skin, left behind in the sediments by an organism
examples of body fossils
Acorns Bones Leaves Shells Teeth
Evolution can be defined as a change in the _____________ ______________ of a __________________ over time.
Gene pool, population
How did Darwin's finches give Darwin important insights into the theory of evolution?
He had originally thought they were a collection of blackbirds, wrens, and finches, but come to find out they were all finches from the same place. That led Darwin to conclude that all life had evolved.
When Darwin compared Galapagos Island mockingbirds to the mockingbirds from mainland South America, what did he notice?
He noticed the variation in the different forms on the island that were not evident on the mainland. This was curious because on the mainland (South America) there was very little variation but on the islands there was a lot of it.
What insights into evolution did Darwin learn from the pigeon breeding experiments?
He saw for what was happening in nature. Give enough time, Darwin and Wallace argues, natural selection could produce new types of body parts, from wings to eyes.
inherited genetic variation
In any species, there are differences between individuals that are passed from generation to generation
According to Darwin, why do individuals compete?
Individuals compete for resources because organisms often produce more young than can survive on the existing resources.
How do radioactive isotopes get into living organisms?
Isotopes are different forms of the same chemical element that are found in all matter. For instance all living material contain a mixture of Carbon-12 and Carbon-14 because they are present in the environment. Carbon-12 is stable which means it is not radioactive and is not useful for dating but Carbon-14 is not stable which makes it radioactive. While an organism is still alive, it maintains the same level of Carbon-14 and other isotopes in its body. But after it dies, the radioactive isotopes begin to decay and they are not replaced by new ones. We use absolute dating on a fossil to make an assumption on how much Carbon-14 was in its body when it was alive.
How does relative dating of fossils work?
It is the process of deciding whether an object is older or younger than others. It's method involves comparisons of the sequence of layers in which fossils are found. And when fossils are found in undisturbed rock, those on the bottom are the oldest and those on top the youngest.
Identify the features of scientific inquiry that were mentioned in the video, Who Was Charles Darwin?
Observation - He spent much of his voyage on the HMS Beagle observing Hypothesis forming - Based on his observation he hypothesized that all life had a common ancestor.
Describe the organisms that lived on Earth prior to the evolution of cyanobacteria:
Prokaryotic cells. They were the dominant life on earth for over a billion years prior to the cyanobacteria.
The narrator on the video points out three differences among the mockingbird species found on the Galapagos Islands. What are they?
Dark chest band Size Beak Shape
As discussed in the video, Who Was Charles Darwin, what information led to Charles Darwin changing his mind about the origin of species?
Darwin noticed patterns of animal behavior, structure and function that tied organisms together in relationships. This convinced him that there had to be an explanation for these patterns that didn't required the divine hand of God.
Survival and reproduction of a particular hummingbird is strongly affected by its ability to feed. Feeding is affected by bill length, bill shape and wing shape. This is an example of what process of natural selection?
Differential survival and reproduction
Some fossil organisms were not buried in sediment. For example, some fossil mosquitoes were trapped in
amber
Hummingbirds compete for nectar, a limited resource. This is an example of what process of natural selection?
struggle for existence
The homology of human, seal and bat limbs
supports the idea of common ancestry because even though the limbs of the human, seal and bat have different shapes, the underlying bones are of the same origin and same character.
Some fossil organisms were not buried in sediment. For example, some fossil dire wolves and sabertooth cats were trapped in
tar
Which of these is not an environmental condition that will affect survival and reproduction of pocket mice?
coat color
In the hummingbird video, what part of the hummingbird's life represented the "struggle for survival"?
competition for nectar
How did cyanobacteria change the world?
created new life forms and iron deposits, which we can use to form steel to make buildings. helped create the formation of plants and the chloroplasts inside plants are actually related to cyanobacteria
What determines the length of an individual hummingbird's bill?
the individuals DNA
Discuss the Snowball Earth hypothesis, including evidence and effect of life.
the surface of earth was frozen entirely or almost entirely. There is evidence supporting this, such as drop stones. Drop stones are stones that were on a part of a continent that were picked up by a glacier, and as the glacier moved so did the rock. When the glacier melted away the rock was then dropped onto the ocean floor. Most of the life on earth was crushed by the overwhelming amount of glaciers.
What is the definition of "science" according to the National Academy of Sciences?
the use of evidence to construct testable explanations and predictions of natural phenomena as well as the knowledge generated through this process.
Adaptation can occur in an individual during its life.
false
Soft structures fossilize better than hard structures.
false
In the hummingbird video, what environmental condition influenced differential survival and reproduction?
flower tube length
Some hummingbirds have long bills while other hummingbirds have short bills. The length of the bill has a strong genetic component. This is an example of what process of natural selection?
genetic variation
Name and describe the four processes of natural selection
genetic variation, overproduction of offspring, struggle for existence and differential survival and reproduction.
In nature, the advantage of being a black mouse on black lava is
greater than 10%
Explain how the body of Spriggina relates to it's lifestyle.
has a head, segments and a tail. Around their head were sensory organs to help them find food. Their long bodies allowed them to move towards food. The segments between their head and tail had hooks and claws. The tails allowed them to get rid of waste products.
Describe the observations on which Darwin based his theory of natural selection.
he spent eight years studying barnacles pigeon breeding, played a significant role both in the development of his theory of natural selection
natural selection
how nature selects for traits in organisms basic mechanism that had brought about the diversity of life on the earth.
Describe artificial selection
humans, not nature, choose the characteristics that we want to develop in plants or animals
Describe struggle for existence using hummingbird example.
hummingbirds compete for nectar, a limited resource.
Some fossil organisms were not buried in sediment. For example, some fossil wooly mammoths were trapped in
ice
differential reproductive success
individuals who inherited a set of characteristics that best allowed them to survive in their environment were the ones who had more offspring
What is the normal color for the pocket mouse?
light
What two types of variation occur in the hummingbird bill length described in the video?
long bills and short bills
Pollen is an example of a tiny microfossil formed without any
mineralization
Describe Overproduction of offspring using hummingbird example.
over a lifetime, a humming has dozens of offspring but only one or two survive to become adults.
What does descent with modifications mean?
refers to the evolution of organisms and how they have been modified over time by natural selection but are descendants from ancestors that may have lacked those specific traits. For example, a bat wing is a highly modified forearm. The bat shares this character as a forearm with other mammals but has been modified for flight.
Describe Differential survival and reproduction using hummingbird example.
Survival and reproduction of a particular hummingbird is strongly affected by it's ability to feed. Feeding is affect ably bill length, shape, and wing shape.
After noticing these differences, Darwin wrote in his notebook that these differences might mean _________________.
That species change
In the hummingbird example, what environmental factor determines which hummingbirds do well and which do poorly?
The DNA they inherited by their parents.
.Sponges
These animals have no tissues and are collections of simple cells held together by a protein called collagen.
Jellies
These animals have two layers of tissues arranged around an interior cavity with one opening, known as the gastrovascular cavity.
What did Charles Darwin and Alfred Russel Wallace figure out?
They both discovered natural selection.
Why do the offspring of these individuals who survived and reproduced have an advantage?
They have an advantage because the variation that allowed their parents to survive has been passed on to them.
If scientist rely on indirect clues, how can they be confident in their explanations of natural phenomena?
They must find a way to test their explanations against more evidence. The better the job that an explanation does, the more confidence the scientist have in it.
Explain this statement: Fractal animals were an evolutionary dead end.
They were immobile creatures which caused them to be incapable of evolving.
Markuelia
This animal is the first known example of an animal with a complete digestive system. Fossils show the gut extended through the animal's body, with a mouth encircled by rings of teeth at one end and a separate opening (the anus) at the other end.
cast fossil
A copy of an original structure (or organism) that formed when sediment leaked into an imprint and hardened
mold fossil
A deep imprint of the whole body of an organism that was buried
mineralization
A fossil formed when minerals carried in water built up in the spaces of an organism and eventually turned into rock
In the scenario in the SW United States, lava replaced the normal sandy habitat for the pocket mouse with a black environment. A mutation for a black mouse (a founding mutation) occurred. If the advantage of being a black mouse on black lava is 10%, how many generations did it take for 95% of the mice to be black in color?
100
What happened when Darwin received a letter from Alfred Russel Wallace?
At this point Darwin realized that he needed to publish his ideas or not get the proper credit for them he deserved.
How does this competition potentially affect an individual's chances of survival and reproduction?
Because there is competition then some will "win" and some will "lose." This means that some may not survive long enough to reproduce and therefore cannot pass their genes on to the next generation.
all of the following are examples of trace fossils
Burrows Coprolites Dinosaur nests Footprints Worm Trails
Which would be more appropriate to use to date Yuka, a Siberian mammoth found in permafrost that is thought to be 10,000 years old?
Carbon-14
metamorphic rocks
Formed when any kind of rock is changed by heat, pressure or chemical activity
igneous rocks
Formed when molten lava cools and solidifies
sedimentary rocks
Formed when sediments are compressed and cemented
Kimberella
Fossils of this animal show that the animal had a muscular foot that was used for movement and a proboscis that was used for shifting through the mud. This is an early ancestor of today's mollusks.
Spriggina
Fossils of this early animal show the first animal body with bilateral symmetry. These animals had distinct heads, body segments and tails.
How did Darwin convince his contemporaries that natural selection was real?
Many of Darwin's scientific peers had their own land on which they grew crops and livestock. They naturally tried to grow better crops and produce better livestock through breeding-- It was then just a small leap for Darwin to get them to accept the idea that nature does the same thing, only not intentionally.
What is significant about Markuelia? What does that tell us about its lifestyle?
Markuelia has a gut that runs through it's front to tail end of the body and it has teeth. This shows that the gut Markuelia had was able to receive nutrients from the food they eat. The teeth shows that Markuelia was probably eating other animal species, meaning it's a predator. Markuelia is one of the first species that we've discovered that had teeth and shows us that animals were evolving to be predatorial.
What effect did the selective breeding experiments on pigeons have on traits in the pigeon population?
Over many generations, this selective breeding would cause the pigeons to evolve
Over a lifetime, a hummingbird has dozens of offspring but only one or two survive to become adults. This is an example of what process of natural selection?
Overproduction of offspring
Explain how the body plan of Kimberella relates to its lifestyle.
Slug-like animal that used its snout to sift through mud.
Describe Genetic variation using hummingbird example
Some hummingbirds have long bills while others have short bills. the length of the bill has a strong genetic component.
The earthquake in Chile
The earthquake gave Darwin the clue from geology that the earth changes over time by geologic processes. He observed that the shoreline had been lifted a few centimeters as a result.
Discuss the concept of endosymbiosis, using cyanobacteria.
The endosymbiosis theory explains how eukaryotic cells may have evolved from prokaryotic cells. Chloroplasts of plants evolved from an endosymbiosis cyanobacterium, living within a mitochondria-containing eukaryotic host cell. Chloroplasts can arise only from preexisting mitochondria and chloroplasts. They cannot be formed in a cell that lacks them because nuclear genes encode only some of the proteins of which they are made.
Describe the geological evidence that supports the Oxygen Catastrophe hypothesis.
The oxygen in the water started reacting with the iron. Causing a rust (iron oxide) to rain down onto the ocean bed. you can see in some rock formations today where the ocean bed has formed into mountains there are red color lines where the iron oxide fell.
The comparison of land and fish vertebrate embryos
The similarity of embryos between land vertebrates and fish vertebrates suggests that we have a similar development and that land animals show this very fishlike development because our ancestors were once fish.
Which of these radioactive elements would be more appropriate to use to date very old rocks that might be 3 billion years old?
Uranium-238 would be appropriate because it has a half-life of 4.5 billion years.
What would you predict would probably happen in an environment where the flowers were short?
You would predict that hummingbird bills would become shorter over time.
Most fossils are formed when an organism is buried in
sediment
Fossils are more likely to be found in
sedimentary rocks
