Chapter 10 Flashcards
(124 cards)
1
Q
Term/Front
A
Definition/Back
2
Q
What significant event occurred around 3.8 billion years ago in the evolution of life on Earth?
A
The emergence of prokaryotes.
3
Q
When did eukaryotes first appear in the history of life on Earth?
A
Around 2 billion years ago.
4
Q
What major evolutionary development occurred approximately 1 billion years ago?
A
The emergence of multicellular life.
5
Q
What is the significance of the Cambrian explosion, which occurred around 535 million years ago?
A
It marked a rapid diversification of life forms in the oceans.
6
Q
When did mammals first appear in the evolutionary timeline?
A
Around 251 million years ago.
7
Q
What significant development in plant evolution occurred around 140 million years ago?
A
The emergence of flowering plants.
8
Q
What did all living things on Earth evolve from?
A
A single-celled prokaryote that existed around 3.8 billion years ago.
9
Q
What significant ability did some offspring of the early prokaryote evolve?
A
The ability to photosynthesize.
10
Q
What major event marked a rise in the diversity of living things?
A
The Cambrian explosion.
11
Q
What is the significance of mass extinctions in Earth’s history?
A
They provide evolutionary opportunities for other species to flourish and diversify.
12
Q
What event is believed to have wiped out three quarters of plant and animal life on Earth?
A
The mass extinction that occurred 65 million years ago, which wiped out the dinosaurs.
13
Q
What does the fossil record provide information about?
A
The history of life on Earth.
14
Q
What conditions are necessary for fossils to be created and last over time?
A
Certain specific conditions that allow for preservation.
15
Q
What usually happens to an animal’s body after it dies?
A
It is either consumed or decomposes completely, leaving no evidence.
16
Q
What is the fossil record?
A
The fossil record refers to all fossils, both discovered and undiscovered, that allow us to study evolutionary changes by comparing living descendants to their long-dead ancestors.
17
Q
What conditions are necessary for fossilization to occur?
A
Fossilization typically occurs when the remnants of an organism are rapidly covered by sediment, protecting them from oxygen, microorganisms, and disturbances that would increase decomposition.
18
Q
How does sediment contribute to the formation of fossils?
A
Over time, sediment layers build upon each other and compact, layer by layer, until pressure cements them together to form sedimentary rock, within which fossilized remains can be found.
19
Q
What are the different forms that fossilized remains can take?
A
Fossilized remains can take many forms, including permineralised fossils, moulds, or casts.
20
Q
What are trace fossils?
A
Trace fossils are indirect evidence of an organism’s existence, such as footprints or nests.
21
Q
What conditions increase the likelihood of fossilization?
A
Conditions include physical protection from scavengers, areas of rapid sediment accumulation, constant cool temperatures, low oxygen availability, and low light exposure.
22
Q
What is a permineralised fossil?
A
A permineralised fossil is formed when mineral-rich groundwater deposits minerals like silica and calcite into organic material, creating a mineral relic.
23
Q
What is the definition of fossil?
A
A fossil is the preserved body, impressions, or traces of a dead organism.
24
Q
What is sediment?
A
Sediment is naturally occurring solid material, such as earth and rock, that is broken down into very fine pieces and typically settles at the bottom of a liquid.
25
What is sedimentary rock?
Sedimentary rock is rock that has formed through the accumulation of sediment that hardens under pressure.
26
What is a mould fossil?
A mould fossil is formed when a living thing decomposes underneath sediment, creating a cavity in the shape of the dead organism.
27
How is a cast fossil formed?
A cast fossil is formed when a mould fossil is filled with sediment.
28
What is a trace fossil?
A trace fossil is a fossil or structure indicating the presence of organisms, rather than the organisms themselves, such as nests, footprints, and burrows.
29
What is relative dating?
Relative dating is a technique used to determine the relative age of a fossil by comparing its position to other fossils or rock in surrounding rock strata.
30
What does the law of fossil succession state?
The law of fossil succession states that fossils closer to the surface are younger than those found below them due to the accumulation of sedimentary layers.
31
What is absolute dating?
Absolute dating is a technique used to determine the absolute age of a fossil by measuring the relative amounts of radioisotopes to their products, also known as radiometric dating.
32
What is the principle of fossil succession?
The principle that fossils of the same age will be in the same layer of sedimentary rock, with fossils in higher or lower layers being younger or older, respectively.
33
What does relative age refer to in paleontology?
The age of a fossil as determined by relative dating techniques, comparing it to other fossils rather than providing an exact age in years.
34
How does the law of fossil succession assist in determining the age of fossils?
It allows scientists to assign a relative age to a fossil based on the age of the rock stratum in which it is found, as sedimentary rock layers develop in chronological order.
35
What are index fossils and why are they important?
Index fossils are fossils from organisms that were geographically widespread and existed for a short, precisely known period of time, helping researchers determine the relative age of new fossils.
36
What characteristics make for the best index fossils?
The species must be physically distinctive, have had a large population, and existed for a short, well-defined period.
37
What is an index fossil?
An index fossil is a group of widespread fossils that existed for a short period and have a known age, used as a reference to determine the age of unknown fossils.
38
What are transitional fossils?
Transitional fossils are fossils that serve as intermediaries between an ancestral species and a descendant species, demonstrating evolutionary changes and traits common to both.
39
How do transitional fossils assist with relative dating?
Transitional fossils help with relative dating by showing the evolutionary link between species that are morphologically distinct, illustrating how certain features evolved over time.
40
What is the significance of transitional fossils?
Transitional fossils are significant because they exhibit traits common to both ancestral and descendant groups, helping to demonstrate evolutionary changes.
41
What is absolute dating in the context of fossils?
Absolute dating involves using the known half-lives of different radioisotopes to measure the absolute age of a fossil.
42
What is the main difference between relative dating and absolute dating techniques?
Absolute dating techniques can be used to calculate the absolute age of a fossil in years, while relative dating does not provide a specific age.
43
What is radioactive dating?
Radioactive dating is a method for determining the age of fossils by comparing the ratio of radioactive isotopes found in the fossil to the stable amount in the atmosphere.
44
What is a radioisotope?
A radioisotope is an unstable element that breaks down over time into a more stable product.
45
What does half-life describe in the context of radioactive dating?
Half-life describes the amount of time before half of the mass of a radioisotope is broken down into predictable and stable products.
46
Why is carbon-14 not useful for dating very old fossils?
Carbon-14 has a relatively short half-life of 5,730 years, making it unsuitable for dating fossils that are millions or billions of years old.
47
How do scientists determine the age of a fossil using radioisotopes?
Scientists measure the ratio of the radioisotope present in the fossil to its breakdown product to calculate the time that has passed since the organism's death.
48
What is a radioactive isotope?
A radioactive atom of a specific element that breaks down into a predictable and stable product.
49
What is half-life in the context of radioactive isotopes?
The time taken for half the mass of a radioisotope sample to break down into its products.
50
What is the dating period in radioactive dating?
The range of time since fossilisation in which a particular radioisotope series can be used.
51
What is radiocarbon dating?
A specific type of radioactive dating that uses the radioisotope series carbon-14 to nitrogen-14.
52
How do scientists determine the age of a fossil using radiocarbon dating?
By measuring the amount of 14C present in the fossil and comparing the 14C:12C ratio in the fossil to that in the atmosphere.
53
What happens to the levels of 14C and 12C when an organism dies?
The levels of 12C remain constant while levels of 14C decay at a known rate.
54
What is radiocarbon dating?
A form of absolute dating used to determine the age of a fossil by measuring the properties of radiocarbon, a radioactive isotope of carbon.
55
Why is dating fossils important?
It allows us to map different changes to species over geological time.
56
What conditions increase the likelihood of fossilization?
Physical protection from scavengers and decomposers, areas of rapid sediment accumulation, constant cool temperatures, low oxygen availability, and low light exposure.
57
What are the two main techniques used to date fossils?
Relative dating techniques, which assign a relative age, and absolute dating techniques, which assign an absolute age in years.
58
What has the fossil record helped us understand?
The development of life over billions of years, from early single-celled prokaryotes to modern-day humans.
59
What are homologous structures?
Homologous structures are physical similarities between two species that indicate they have a common ancestor.
60
How can structural morphology be used to assess relatedness between species?
Structural morphology involves looking for similarities in physical features, such as skeletal structures, to determine the relatedness between different species.
61
Can you give an example of homologous structures?
An example of homologous structures is the upper limb of humans, cats, whales, and bats, which share a similar bone structure despite having different shapes and functions.
62
What does the presence of homologous structures suggest about species evolution?
The presence of homologous structures suggests that the species diverged from a common ancestor that had a similar limb structure.
63
What is divergent evolution?
Divergent evolution is the process in which a common ancestor evolves into two or more descendant species, often due to adaptation to different selection pressures.
64
What are analogous structures?
Analogous structures are structures that serve similar biological functions but are not derived from a common ancestor, indicating convergent evolution.
65
What is convergent evolution?
Convergent evolution is the process in which distantly related species evolve similar traits over time due to similar selection pressures.
66
What are vestigial structures?
Vestigial structures are remnants of organs or structures that had a function in an organism's ancestors but have lost their original purpose due to changing selection pressures.
67
How can vestigial structures be used in evolutionary studies?
Vestigial structures can be used to infer relatedness between species, as they indicate common ancestry despite having no current function.
68
What is an example of a vestigial structure in humans?
The human coccyx, or tailbone, is a vestigial structure that is a remnant of our ancestors' tail, which was used for balance.
69
What are vestigial structures and give examples?
Vestigial structures are features that have lost all or most of their usefulness due to evolution by natural selection. Examples include pelvic bones in snakes and whales.
70
Why do snakes and whales have pelvic bones despite not having legs?
Snakes and whales have pelvic bones because they are descendants of reptiles and mammals, respectively, that had legs.
71
What is molecular homology?
Molecular homology is the study of the similarities between organisms at a DNA and amino acid level to establish relatedness.
72
What are conserved genes?
Conserved genes are genes that have remained largely unchanged throughout evolution and are found across the genomes of many different species.
73
How is amino acid sequence similarity used in evolutionary studies?
Amino acid sequence similarity is used to determine how related different organisms are by analyzing proteins from conserved genes found in various species.
74
What is the primary function of Haemoglobin (Hb) in different species?
Haemoglobin plays an important role in carrying oxygen from the lungs to the cells around the body.
75
How many polypeptide chains compose Haemoglobin, and what are their types?
Haemoglobin is composed of up to 4 polypeptide chains: 2 alpha chains and 2 beta chains.
76
Which species has the highest level of similarity in their haemoglobin amino acid sequence compared to humans?
Chimpanzees have the highest level of similarity in their amino acid sequence for haemoglobin compared to humans.
77
What is Cytochrome c and where is it found?
Cytochrome c is an enzyme present in mitochondria that consists of 104 amino acids.
78
Which organism shows more similarity in cytochrome c amino acid sequence to humans, rats or yeast?
Rats show more similarity to humans in the cytochrome c amino acid sequence than yeast does.
79
What is cytochrome c?
An enzyme found in mitochondria that carries electrons in aerobic and anaerobic respiration reactions.
80
What is mitochondrial DNA (mtDNA)?
Circular DNA found in mitochondria.
81
How can DNA sequences be used to determine evolutionary relatedness?
By comparing the DNA sequences of different species, a higher similarity in DNA sequence implies a closer level of relatedness.
82
What are the nitrogenous bases found in nucleotides?
Adenine (A), cytosine (C), guanine (G), thymine (T), and uracil (U).
83
What does a comparison of DNA sequences reveal about humans, rats, and yeast?
Humans and rats have three nucleotide differences, while humans and yeast have seven nucleotide differences, indicating that rats are more closely related to humans than yeast.
84
What is DNA?
A double-stranded nucleic acid chain made up of nucleotides that carries the instructions for proteins required for cell and organism survival.
85
What is a nucleotide?
The monomer subunit of nucleic acids, made up of a nitrogen-containing base, a five-carbon sugar molecule, and a phosphate group.
86
What is a genome?
The complete set of DNA housed within an organism.
87
What is a genome?
The complete set of DNA housed within an organism.
88
Where is nuclear DNA located?
In the nucleus of a cell.
89
What do amino acid and DNA sequence analysis help determine?
The relatedness between different organisms.
90
When should scientists use DNA sequence analysis over amino acid sequence analysis?
When species are closely related and share very similar sequences for certain proteins.
91
What is a limitation of analyzing amino acid sequences?
Closely related species are likely to share very similar sequences for certain proteins.
92
What can scientists compare to determine the relatedness of different species?
Whole genomes of different species.
93
What does a higher degree of similarity between genomes indicate?
The species are more related and more recently diverged from a common ancestor.
94
Which two species are mentioned as having very similar genomes?
Humans and chimpanzees.
95
What is a phylogenetic tree?
A phylogenetic tree is a diagram that shows the evolutionary relationships between different species.
96
What is the purpose of phylogenetics?
Phylogenetics is the study of the evolutionary history of an organism or group of organisms, aiming to describe their relationships to other organisms, both past and present.
97
What components make up a phylogenetic tree?
A phylogenetic tree includes components such as a root, branches, nodes, and leaves.
98
How can phylogenetic trees be useful?
Phylogenetic trees can display the timeline of lineages, relatedness between taxa, shared characteristics of different taxa, and the structure of the tree itself.
99
What does evolutionary relationship refer to?
The relatedness of organisms based on shared ancestry.
100
What is a lineage?
A direct sequence of species that evolved from a common ancestor.
101
What is a taxon?
A unit of biological classification into which related organisms are classified.
102
What does the root of a phylogenetic tree represent?
The most recent common ancestor for all members of the tree.
103
What does a branch on a phylogenetic tree represent?
An evolutionary path.
104
What is a node in a phylogenetic tree?
The splitting point between two branches, representing a speciation event.
105
What does a leaf represent on a phylogenetic tree?
The current (or final) form of a species.
106
How can phylogenetic trees be read to determine relatedness?
They can be read backwards to determine the most closely related species to a particular taxon.
107
What does node A represent in the context of humans and monkeys?
The most recent common ancestor of humans and monkeys.
108
What does node B separate in the phylogenetic tree?
Humans and monkeys from dolphins and sheep.
109
What does the branch length in a phylogenetic tree with a timescale represent?
The branch length represents time.
110
How do you determine the first divergence in constructing a phylogenetic tree?
Identify the trait shared by the largest number of animals, such as the presence of four legs.
111
What trait is used to branch off the bony fish in the phylogenetic tree example?
The absence of four legs.
112
Which group of animals branches off before the fur trait in the phylogenetic tree?
Amphibians branch off before the fur trait.
113
What is the relationship between marsupials and placental mammals in the phylogenetic tree?
Both marsupials and placental mammals branch directly from the trait fur.
114
What does the lack of a node between species Y and Z in a phylogenetic tree indicate?
It indicates that the exact divergence point between species Y and Z is unknown.
115
What does the break between species W and X in a phylogenetic tree suggest?
It suggests that W is possibly an ancestor of X, but there is no evidence of transitional fossils to support this hypothesis.
116
What does it mean when a branch with species S does not reach the end of the phylogenetic tree?
It indicates that species S is extinct.
117
What does it signify when a node splits into three or more lineages in a phylogenetic tree?
It signifies that it is unclear which species diverged from the others first, often due to insufficient data or closely occurring speciation events.
118
What is adaptive radiation?
Adaptive radiation is the rapid divergent evolution of a species, producing a wide array of species/forms.
119
How can genetic material be exchanged between groups after they have diverged?
Genetic material can be passed between groups, as seen in the interbreeding of modern humans and Neanderthals, which is depicted using a line between branches in phylogenetic trees.
120
What are phylogenetic trees used for?
Phylogenetic trees are diagrams used to show the relatedness between organisms.
121
How can we understand the relatedness of organisms?
By interpreting phylogenetic trees, we can understand how related some organisms are to others.
122
What can be traced back using phylogenetic trees?
Phylogenetic trees allow us to trace back the lineage of different groups of organisms.
123
How is a phylogenetic tree constructed?
A phylogenetic tree can be constructed by looking at the traits shared by a large group of species.
124
Created on OmniSets
https://www.omnisets.com/set/250359/
