Evolution Flashcards
(133 cards)
1
Q
Scientists estimate that the earth, moon, and other planets are about how old?
A
4.5 billion years.
2
Q
How do scientists estimate the age of the earth (what process do they use)?
A
Radiometric dating.
3
Q
What is radiometric dating for determining the age of the earth?
A
Using isotopes that are old, such as uranium, which turns into a different element over time. Look at the oldest rocks and observe the amount of isotope, less material=older.
4
Q
Define half-life.
A
The time it takes for half of a substance to decay and turn into a different isotope.
5
Q
What is the half-life of carbon?
A
5,730 years.
6
Q
What is the half-life of uranium?
A
4.5 billion years.
7
Q
How much uranium should we expect to see today?
A
1/2 of the original amount because we have gone through one half-life.
8
Q
What is Carbon 14?
A
It is an isotope with extra neutrons. All of our cells have the same ratio of carbon 14. It is useful for carbon dating because when we die, the carbon in our bones stays and decreases over time.
9
Q
What is spontaneous generation/origin?
A
The idea that life could come from non-living things.
10
Q
What was the “evidence” to support spontaneous generation?
A
If you leave meat out, maggots will just “appear.”
11
Q
How was spontaneous generation disproven?
A
An experiment was conducted. An open container with meat had maggots, a cork-sealed container had no maggots anywhere, and a gauze-covered container had no maggots on the meat, but there were maggots on top of the gauze.
12
Q
What are two origin of life theories?
A
It came from outer space, or primordial soup.
13
Q
What is the theory of the origin of life coming from outer space?
A
The theory is that there was life on a comet that crashed to earth.
14
Q
What is the primordial soup theory?
A
Since early life was supposedly from the oceans, it is theorized that there was a puddle of materials, such as amino acids, that could form simple cells with the help of electricity.
15
Q
What is one piece of evidence for the primordial soup theory?
A
Miller and Urey’s experiment.
16
Q
What was Miller and Urey’s experiment?
A
They took gases present on earth that were unrelated to life (methane, hydrogen gas, H2O gas, etc.) and added a spark to simulate lightning. Organic compounds could form in this way as long as there was water. It produced simple amino acids.
17
Q
What was the significance of Miller and Urey’s experiment?
A
It did not create life, but it created things necessary for life to show up.
18
Q
What is the issue with the primordial soup theory?
A
The absence of the ozone, which would result in dangerous UV light passing through life and destroying DNA.
19
Q
Because of the lack of ozone, where do scientists think early life was found?
A
In deep-sea vents. The further down, the greater UV protection. Also, hydrothermal vents have water and certain necessary gases for life.
20
Q
What is the first step in the formation of life?
A
Simple organic molecules (sugars, amino acids, fatty acids, nitrogenous bases). The formation of these was shown by the Miller and Urey experiment.
21
Q
What is the second step in the formation of life (after simple organic molecules)?
A
Complex organic molecules (carbohydrates, proteins, phospholipids, nucleotides). Certain experiments demonstrate how phospholipids can show up in the right conditions.
22
Q
When you mix phospholipids with water, what do you get? (Third step in the formation of life).
A
Protobionts and microspheres.
23
Q
What are protobionts and microspheres?
A
A microsphere is a fat that is balled up with water on the outside. The phospholipid creates a container. It creates a different environment on the inside called a protobiont (because it is necessary to separate the inside environment from the outside of a protocell).
24
Q
What do microspheres and protobionts lead to? (Fourth step in the formation of life)
A
Prokaryotic cells like archaebacteria.
25
What do scientists say is the oldest and simplest form of bacteria? What is the evidence for this?
Archaebacteria. There is fossil evidence, but no experimental evidence for this because we cannot create bacteria in a lab.
26
What organism was likely the dominant form of life for a very long time?
Archaebacteria.
27
What is endosymbiosis?
A mutualistic relationship in which one organism lives inside another. Endo=inside, symbiosis=living together.
28
What structure inside our cells resembles archaebacteria?
Mitochondria.
29
How are mitochondria similar to archaebacteria?
They have their own unique DNA, they can reproduce on their own, and they are similar in size and shape to bacteria.
30
How does endosymbiosis relate to mitochondria?
Mitochondria may resemble prokaryotic archaebacteria, but they are in a symbiotic relationship with our cells. They cannot survive without our cells, and our cells cannot survive without them.
31
How does endosymbiosis relate to chloroplasts?
In a similar process to mitochondria, chloroplasts could have once been separate organisms taken in by similar cells and then formed a symbiotic relationship.
32
What is the support for endosymbiosis?
1. Mitochondria and chloroplasts are similar in size to prokaryotes. 2. Mitochondria and chloroplasts have their own DNA and ribosomes. 3. Mitochondria and chloroplasts replicate by binary fission during cell division.
33
What is the order of events from the formation of earth to humans existing?
Formation of earth (hot, molten); formation of core; moon formation; formation of zircon crystal; formation of acasta; isua; apex chart (earliest fossils); rise in atmospheric oxygen; first cell with a nucleus; first hard-shelled animals; dinosaurs; humans.
34
What is zircon crystal?
One of the first solid rocks.
35
What is acasta?
The oldest rock that has not been recycled by plate tectonics.
36
What is isua?
First sedimentary evidence for oceans and earliest isotopic evidence for life.
37
According to the apex chart, what do the earliest fossils resemble? How old are they?
They resemble bacteria. They are about 3.5 billion years old.
38
How long did it take for life to show up?
1 billion years.
39
When did atmospheric oxygen show up?
2 billion years ago.
40
How did atmospheric oxygen show up?
Cyanobacteria, which were the first photosynthetic organisms. They allowed for more life.
41
What did the presence of oxygen from the cyanobacteria allow to happen?
It allowed the ozone to form.
42
What did the development of the ozone allow to happen?
It allowed a huge number of new creatures to show up, specifically land animals because it acts as a shield from UV radiation.
43
Before the ozone, where was the only habitable place on earth?
The ocean.
44
Why are mass extinction events significant for new life?
Exctintion events lead to new species. After extinction events, the number of taxonomic species increases because the change in the environment (volcanic ash clouds, temperature changes, extinctions, etc.) open up new niches for organisms to fill.
45
What did the end of the dinosaur period lead to?
The start of the mammal hypothesis because the dinosaur extinction created space for mammals.
46
Who was Lamarck?
The first person to propose an explanation for evolution. He proposed the law of acquired characteristics.
47
What is the law of acquired characteristics?
The idea that evolution occurs through the use and disuse of physical features, like giraffes' necks getting longer so that they could get food.
48
Who was Lyell?
One of the first people to show that the earth is very old using principles of geology.
49
Who was Malthus?
An economist who looked at necessary human resources and learned that overpopulation leads to the depletion of resources.
50
Who was Charles Darwin?
A naturalist and a theologian who toured the world on his ship, the Beagle, as he made observations and collected specimens.
51
What did Darwin do during his journey?
He observed and recorded various plants and animals, and he observed farmers breeding crops and animals for better characteristics. These helped him make his work.
52
Define evolution.
A change in allele frequency over time.
53
What was Darwin's explanation for natural selection?
The environment, not the organism/individual, determines the fit trait. The organism cannot decide to adapt or evolve.
54
What are Darwin's four requirements for natural selection?
Variation, overpopulation leads to a struggle for survival/competition, one variation is better able to survive, and reproduction passes on the fit trait.
55
What is variation?
There are different possible alleles for a gene and they are displayed within a population. Ex: the peppered moth has two colors: Black and peppered.
56
What is an example of overpopulation (or just a threat in general) leading to a struggle for survival/competition?
Ex: If there was a high level of predation from birds, not all the peppered moths would survive to reproduce.
57
What is an example of one variation being better able to survive/being more fit?
The light green lichens provide a way for the light/pepper colored moths to hide themselves from predators.
58
What is an example of reproduction to pass on the fit trait for survival of the fittest?
Now, since the camouflage helped the pepper colored peppered moths to survive, more of that variation will survive and reproduce. This will now be the greatest/most common allele frequency.
59
What is artificial selection?
Humans deciding the better/fit trait, even if it is not necessarily better for survival.
60
What are some examples of artificial selection?
Breeding racehorses, breeding certain types of dogs like pugs and dachshunds, artificially selected size for wheat seed.
61
What is sexual selection?
Within a species, certain traits are more "fit" (or at least desirable) because the member of the opposite sex tends to look for those traits.
62
What are some examples of sexual selection?
A female bird choosing a male bird based on his dance or call, flowering plants trying to attract pollinators, female peacock looks for the male with the best tail feathers.
63
Is sexual selection always beneficial for survival? Explain and give an example.
No, because certain desirable traits can actually make it harder to survive. For example, a female bird might prefer a brightly colored male, but that male will have a harder time hiding from predators.
64
Define adaptation.
Any trait that benefits the individual by helping it in some way.
65
Define morphological adaptation.
An adaptation relating to shape, such as the streamlined shape of a fish.
66
Define behavioral adaptation.
An adaptation relating to behavior, like a bear hibernating when food is scarce.
67
Define physiological adaptation.
An adaptation relating to function, like a snake producing venom to make it easier to catch prey.
68
List the three kinds of adaptations.
Morphological, physiological, and behavioral.
69
List some examples for evolutionary evidence.
Homologous structures, vestigial structures, fossils, embryology, industrial melanism, antibiotic-resistant bacteria.
70
What is a fossil?
It is a trace left over from organisms from long ago. They are mostly hard structures from an organism's body that found the right sediment, allowing minerals to leach in and replace the bone.
71
Aside from bones, what are some other types of fossils?
Imprints of skin or tissue, fossilized poop (coprolite).
72
Does DNA have a half-life? Why is there an issue presented because we found DNA in a dinosaur skeleton?
DNA does have a half life (521 years). Finding DNA in a dino skeleton shouldn't have happened because DNA wouldn't have lasted long enough to stay within the bones. (This suggests a much younger skeleton.)
73
What are two ways to figure out fossil age?
Radiometric dating and relative dating.
74
What is radiometric dating for determining the age of fossils?
Relying on isotopes and the fact that each radioactive element has a half-life. Using this to determine how old the fossil is.
75
If we have 100 radioactive isotopes, after one half-life we will have...After another half life we will have...and after a third half-life we will have...
50, 25, 12.5.
76
What is relative dating? Also give an example.
Determining the age of something relative or comparative to another. Ex: If we have layers of sedimentary rock, we know that the bottom layers are older than the top layers.
77
Why is relative dating useful for fossils?
Because we find the most fossils in sedimentary rock, we can determine how old the fossil is in comparison to the layers it is buried in.
78
Where do we typically find sedimentary rock?
Wet lowlands, slow-moving streams, lakes, areas near volcanoes.
79
Why is uranium a bad choice for radiometric dating in fossils?
It has not reduced enough because it has a very long half-life.
80
Why is C14 (carbon 14) also a bad choice for radiometric dating in fossils?
Its half-life is too short; there would be almost nothing left over in the dinosaur bones.
81
What does C14 turn into over time?
N14 (nitrogen 14).
82
How do you use radiometric dating to determine a fossil's age?
Since there is some percent of the isotope left, identify how much isotope there is now and how much there would've been when the animal died. Match this percentage up with the half-life.
83
What is one piece of evidence supporting evolution that we have found from the fossil record? (Hint: It has to do with the evolution of one particular animal.)
Whale evolution over 60 million years. It appears that whales were very similar to a common ancestor in their form. We can use this to help us determine the relationship between them, also based on location, age, physical form, etc.
84
What are some reasons for the gaps in the fossil record?
Not all fossils have been discovered, not all organisms can form fossils due to body composition or location (dry areas=no bones left over), and adaptations are not always morphological and therefore cannot be seen in fossils.
85
What are homologous structures?
Structures that are similar between two different organisms, indicating a possible common ancestry.
86
What are some examples of homologous structures?
Cats and humans have similar arm structures.
87
What are vestigial structures?
They are structures that organisms may have that were useful in previous ancestors, but not anymore. They are now useless and not beneficial for survival.
88
What are some examples of vestigial structures?
Tail bone, ear wiggling (other animals benefit by wiggling their ears, but not humans), appendix, and wisdom teeth apparently suggest common ancestry with organisms with the same structures.
89
What is comparative embryology?
Looking at how common ancestors have similar-looking embryonic development. As the embryos grow, however, the differences become more pronounced.
90
What are some examples of comparative embryology?
Human development looks very similar to rabbits, cows, and pigs. Chickens develop similarly to tortoises. Salamanders develop similarly to fish as embryos.
91
What do humans seem to be more closely related to based on comparative embryology? What do we seem to be more distant from?
We are similar to rabbits, cows, and pigs. We are distant from fish and salamanders.
92
What is DNA hybridization?
Comparing DNA nucleotide sequence similarities. 500 genes are shared among all organisms, and we can look for genes that humans and chimps or humans and bacteria share for example.
93
What is protein analysis?
Comparing amino acid similarities: do they have the same function between two different organisms? We can see how closely related two organisms are, and we can look at mutations, DNA, etc.
94
What is industrial melanism?
The ability of gene frequencies to change between generations due to pollution.
95
What is an example of industrial melanism?
The initial population of peppered moths may be mostly light, but after pollution, many may be mostly dark to better camouflage with the pollution.
96
How do bacteria provide evolutionary evidence?
We can observe their resistance to antibiotics.
97
What is one way bacteria develop antibiotic resistance?
Artificial selection. If you start with bacteria and add ampicillin (antibiotic), some mistakes in a few bacteria from binary fission can result in mutations that allow those bacteria to survive. The rest die, but the survivors reproduce and pass on the resistance gene, making the next generation almost completely resistant.
98
Define divergence/speciation.
The end result of evolution, the process of forming new species from existing species.
99
What is adaptive radiation?
The process of speciation/the process by which organisms diversify (sometimes rapidly) into a multitude of new forms.
100
What is geographic isolation?
Geographical features, such as rivers, separate two populations of the same species, like Darwin's finches. The longer the separation, the higher the chances of the two populations never interbreeding and therefore becoming a new species.
101
What is reproductive/genetic isolation?
When slight changes in a big population, or in two populations in the same area, result in two populations not interbreeding even though they are genetically similar and live in the same area.
102
What is an example of genetic/reproductive isolation?
Different zebra mating seasons.
103
What is gradualism?
The idea that small changes over many years can lead to big changes and new species.
104
What is punctuated equilibrium?
A small change or mutation led to an adaptation which led to a new species. It is a quick, small change.
105
What is divergent evolution?
Two or more species were descended from the same common ancestor through adaptive radiation. Ex: Giraffes and cows have similar structure because they are from a common ancestor.
106
What is convergent evolution?
Although the species are not from a common ancestor, they end up with similar adaptations due to their environment.
107
What is bioinformatics?
Tools used in comparative biochemistry for evolutionary relationships.
108
What is comparative biochemistry?
Looking at DNA, RNA and proteins and their sequences/images.
109
What does DNA sequencing help with?
It identifies mutations in DNA.
110
What does RNA sequencing help with?
It identifies tissue-specific gene expression.
111
How can you look at proteins?
Protein 3D structure visualization.
112
When looking at DNA sequences between two organisms, the amount of change in the sequences determines...
Evolutionary relatedness.
113
What are internal nodes?
Points on a cladogram/phylogenetic tree that show a common ancestor.
114
What are external nodes?
The organism we are looking at on a cladogram.
115
What is the function of the outgroup?
It puts in perspective how closely related the rest of the organisms are.
116
A change in a population's genetics over several generations is called:
Evolution
117
What is one piece of evidence for evolution regarding structures that once had functions but no longer do?
Vestigial structures.
118
Humans selecting for desired traits is called:
Artificial selection
119
Two structures in different organisms that are very similar in makeup and therefore seem to support a common ancestor are called:
Homologous
120
The dating of a fossil that involves knowing the half-life of an isotope is called:
Radiometric dating.
121
Is industrial melanism a slow process (>10 years) or a relatively fast process (<10 yrs)?
Slow
122
A theory that helps explain why we don't always see gradualism and progressive change in the fossil record because mutations cause dramatic vs gradual changes or behavioral or physiological changes is called:
Punctuated equilibrium
123
This term is used to describe evolution where different species evolve because they no longer can mate due to temporal isolation, gametic isolation, behavioral or mechanical.
Reproductive/genetic isolation
124
Is genetic drift something that has increased the rate of evolution of new animal, especially mammalian species?
No
125
What has increased the rate of evolution of new animal, especially mammalian species?
Mass extinction events, build-up of ozone, build-up of oxygen.
126
Evolution of similar traits such as fins due to similar environmental pressures (living in water) is a result of this type of evolution.
Convergent.
127
Phylogeny is the study of evolutionary relationships, a phylogenetic tree is also called a:
Cladogram
128
Is a brightly colored peacock an example of sexual selection or speciation due to geographic isolation?
Sexual selection.
129
Which two scientists influenced Darwin? Which one did not?
Malthus and Lyle influenced him; Lamarck did not.
130
Current cladograms use this kind of evidence to support them:
Molecular/DNA
131
What are three possible ways for new variations in a population's gene pool to arise?
Mutations, gene flow, and the founder effect.
132
The most important organism responsible for the initial buildup of the earths oxygen are?
Cyanobacteria
133
Is random mating a possible way for new variations in a gene pool to arise in a population?
No.
