Module 4 Flashcards
(201 cards)
1
Q
What did Chinese philosophers believe about the world?
A
The world is in constant transformation
This perspective emphasizes change and dynamism in nature.
2
Q
What was the classic Greek and Roman debate about?
A
Whether species change or remain fixed over time
This reflects early philosophical discussions on the nature of life and species.
3
Q
How were species viewed in Europe historically?
A
Species were considered special creations, fixed for all time
This idea was prevalent before the acceptance of evolutionary theory.
4
Q
What are the two main ideas proposed by Darwin?
A
- Descent with Modification
- Natural Selection
5
Q
What does ‘Descent with Modification’ imply?
A
- Common ancestor
- Inherited traits
- Occasional changes
6
Q
What is the concept of Natural Selection?
A
- Variation within populations
- Individuals struggle to survive and reproduce
- Successful individuals pass on their traits
- Populations adapt over generations
7
Q
Who influenced Darwin’s understanding of gradualism?
A
Geologists Hutton and Lyell
Their work suggested that slow processes shape geological features over time.
8
Q
What did Hutton propose regarding geological features?
A
Gradual mechanisms could explain geological features
This contrasted with the fundamentalist view of a young Earth.
9
Q
What is the main idea of gradualism?
A
Slow and subtle processes shape the Earth and cause substantial biological change
Gradualism is key to understanding both geology and evolution.
10
Q
What did Malthus calculate about population growth?
A
The rate of population growth was greater than the rate of food supply increase
This idea introduced the concept of competition for resources.
11
Q
How did Malthus influence Darwin’s thinking?
A
Darwin concluded that better-adapted individuals would survive and reproduce more
This led to the concept of ‘struggle for survival’ in Natural Selection.
12
Q
What was Lamarck’s hypothesis of evolution?
A
Transmutation: Evolutionary change occurs over time, with acquired characteristics passed to offspring
Examples include the giraffe’s neck and blacksmith’s arms.
13
Q
What did Lamarck believe about organ use?
A
If an animal used an organ, it would become larger and this could be inherited
This idea is known as the inheritance of acquired characteristics.
14
Q
What was Darwin’s view on Lamarck’s ideas?
A
Darwin agreed that gradual evolution could occur via small changes but focused on variation within populations
Darwin’s understanding of inheritance was limited.
15
Q
What was the duration of Darwin’s voyage on the Beagle?
A
1831-1836
This voyage was crucial for Darwin’s observations about biodiversity.
16
Q
In what year did Darwin describe his theory of evolution?
A
1844
This essay outlined his observations and hypotheses about adaptations.
17
Q
What does ‘Natural Selection’ as a process involve?
A
Individuals with certain inherited traits leave more offspring
This mechanism explains adaptation.
18
Q
What is the difference between Natural and Artificial Selection?
A
Artificial selection is when breeders choose which individuals will breed based on traits
This can lead to rapid changes in species.
19
Q
List Darwin’s observations regarding populations.
A
- Members of a population vary in inherited traits
- All species can produce more offspring than the environment can support
20
Q
What is Darwinian Selection?
A
Individuals with advantageous traits tend to leave more offspring
This leads to the accumulation of favorable traits over generations.
21
Q
What is a possible objection to Darwin’s theory regarding intermediate forms?
A
Lack of intermediate forms in nature may lead to extinction of these forms
Successful adaptations can out-compete others.
22
Q
What issue arises with complex, specialized structures in evolution?
A
Intermediate forms may not be functional, but they can still serve some purpose
Examples include gliding animals and simple light-sensing eyes.
23
Q
True or False: Many features of organisms are adaptive and produced by natural selection.
A
False
Some features may seem non-adaptive due to unknown functions.
24
Q
What does modern population genetics help explain?
A
Non-adaptive features in organisms
It provides insights into traits that may have been useful in the past.
25
Who traveled to the Amazon and East Indies, inspired by other naturalists?
Alfred Russel Wallace and naturalist Bates
## Footnote
They were influenced by the travels of accomplished naturalists like Darwin.
26
What essay did Wallace write to solidify his ideas on natural selection?
"On the tendencies of varieties to depart indefinitely from the original type"
## Footnote
This essay was sent to Darwin and linked Malthus' ideas on population growth with evolution.
27
What phrase did Wallace use to describe the concept of natural selection?
"Survival of the fittest"
## Footnote
This concept suggests that the most fit organisms survive and pass their traits on to future generations.
28
Which concept did Wallace's essay precede in publication?
Darwin's own work on natural selection
## Footnote
Wallace's ideas were published before Darwin's, highlighting the independent development of the theory.
29
What key difference did Darwin and Wallace have regarding the inheritance of traits?
Darwin believed in the inheritance of acquired traits; Wallace rejected Lamarck's idea
## Footnote
Wallace did not provide a better suggestion for explaining variation.
30
What did Darwin stress as the cause of natural selection?
Competition
## Footnote
Darwin emphasized competition among organisms in the process of natural selection.
31
What did Wallace emphasize regarding species adaptation?
Environmental pressures
## Footnote
Wallace highlighted that environmental pressures forced species to adapt to their surroundings.
32
What controversy surrounded Darwin's idea of evolution by natural selection?
It was met with huge controversy
## Footnote
The debate between Wilberforce and Huxley in 1860 exemplified this controversy.
33
Who was known as 'Darwin's bulldog' during the famous debate?
Huxley
## Footnote
Huxley defended Darwin's theory against Wilberforce.
34
What was the outcome of the debate over Darwin's theory by 1870?
Darwin's idea of Natural Selection was accepted by most scientists
## Footnote
This acceptance occurred within a decade after the debate.
35
What did Darwin and Wallace not understand about inheritance?
How traits were inherited
## Footnote
They lacked knowledge about genetic inheritance.
36
Who conducted significant research on inheritance at the same time as Darwin and Wallace?
Mendel
## Footnote
His work on pea plants was hidden until after his death in 1900.
37
What are the key ideas from Mendel's work?
* Offspring receive characteristics from both parents
* Only the dominant characteristic trait is expressed
## Footnote
Mendel's findings laid the groundwork for modern genetics.
38
What triggered a huge effort from biologists regarding evolution and genetics?
The revelation of Mendel's work
## Footnote
This led to studies linking environmental pressures to characteristic selection in populations.
39
What is the Modern Synthesis in evolutionary biology?
It brought Darwin's Natural Selection back to the center of evolutionary theory
## Footnote
Huxley played a significant role in this synthesis.
40
How has the structure of DNA changed evolutionary biology?
* Better understanding of mutation processes
* Better understanding of effects of mutations
* Genome-wide genetic studies
* Importance of chromosome structure
* Complexity in evolutionary models
## Footnote
These discoveries have added realism to the study of evolution.
41
What is natural selection?
The unequal survival and reproduction of organisms resulting in the preservation of favourable adaptations.
42
What are the two requirements for evolution by natural selection?
* Heritable variation in a population
* Non-random survival and reproduction
43
Define microevolution.
Any change in the frequency of genetic variants in the population.
44
How does natural selection relate to microevolution?
Natural selection is a form of microevolution.
45
What is a population in biological terms?
A group of individuals of the same species that live in the same area and interbreed.
46
What distinguishes most distinct populations?
They are often separated by geographic barriers or other factors like behavior and timing of breeding.
47
What is the smallest unit of evolution?
Population.
48
Do individuals evolve?
No, populations evolve.
49
What causes heritable trait variation?
DNA mutations at certain loci in the genome.
50
What are heritable variants called?
Alleles.
51
What is non-heritable variation?
Variation that is not due to genetic differences but rather environmental factors.
52
Give an example of non-heritable variation.
* Coloring your hair a different color
* Traits affected by diet in caterpillars
53
What is a dominant allele?
An allele that has the same phenotype in both heterozygotes and homozygotes.
54
What is a recessive allele?
An allele that has no effect in a heterozygote.
55
What is a codominant gene?
A gene where a heterozygote has an intermediate phenotype.
56
What are Mendel's basic ideas about genetics?
* Genetic elements (alleles) come in pairs
* Alleles do not change over generations
* Pairs of alleles separate during gamete formation
57
What does a Punnett square show?
Parental gametes and genotypes of the next generation.
58
Define gene pool.
The total of all copies of every allele of every gene in all members of the population.
59
What does evolution represent in terms of allele frequencies?
The change in allele frequencies over generations.
60
What is Hardy-Weinberg Equilibrium (HWE)?
A state where a population is NOT evolving, and allele frequencies remain constant.
61
What does the Hardy-Weinberg Equation represent?
p² + 2pq + q² = 1, used to predict genotype frequencies.
62
Under what conditions is a population at Hardy-Weinberg Equilibrium?
* Extremely large
* Isolated with no gene flow
* Random mating
* No mutation
* No natural selection
63
What does it indicate if genotypes in a population don't fit expected proportions?
At least one assumption of the HWE model must not hold, meaning the population might be evolving.
64
What are potential causes for deviations from Hardy-Weinberg Equilibrium?
* Natural selection
* Mutations
* Genetic drift
* Gene flow
* Non-random mating
65
What is mutation?
Changes in the DNA sequence
## Footnote
Causes include radiation, viruses, and carcinogens
66
What are the types of mutations?
* Deletion
* Duplication
* Inversion
* Insertion
67
What is genetic drift?
Random changes in the frequencies of alleles from generation to generation
68
What causes genetic drift?
Accidents of sampling during reproduction and life
69
How does population size affect genetic drift?
The smaller the population, the stronger the genetic drift
70
What is the founder effect?
New areas colonised by a small number of founders from a larger population
71
What is a genetic bottleneck?
An extreme genetic drift event when a population is very small
72
What are the consequences of a genetic bottleneck?
* Random genetic changes
* Limited genetic diversity
* Increased susceptibility to disease and inbreeding
73
What is gene flow?
The movement of individuals and their alleles among populations
74
How does gene flow affect allele frequency?
It changes the frequency of alleles in recipient populations
75
What is natural selection?
Reproductive success depends on traits, affecting allele frequencies
76
What determines an organism's fitness?
* Survival
* Reproduction
77
What is absolute fitness?
Total number of healthy offspring produced
78
What is relative fitness?
Reproductive success relative to others in the population
79
What is continuous genetic variation?
Common in nature, cannot typically be attributed to particular loci
80
What are the types of natural selection?
* Directional Selection
* Stabilising Selection
* Disruptive Selection
* Sexual Selection
* Balancing Selection
81
What does directional selection favor?
One extreme of the distribution
82
What is stabilising selection?
Removes extreme phenotypes, shifting towards optimum phenotype
83
What does disruptive selection favor?
Variants at both ends of the distribution
84
What is sexual selection?
Traits that affect ability to attract or access mates
85
What is heterozygote advantage?
Heterozygotes are fitter than both homozygotes
86
True or False: Natural selection is random.
False
87
What does natural selection increase?
The frequency of beneficial alleles
88
What is adaptation?
Features that have evolved through natural selection for a particular function
89
What shapes evolution by natural selection?
Geography and historical processes
90
What is homology?
Similarity resulting from shared ancestry
91
What is convergent evolution?
Natural selection produces similar features in organisms with different ancestry
92
Fill in the blank: Natural selection is constrained by _______.
[existing structures and historical constraints]
93
What is non-random mating?
Occurs when there is a bias for or against mating with similar individuals
## Footnote
Non-random mating can lead to changes in genotype frequencies in a population.
94
What is assortative mating?
Mating of similar individuals
## Footnote
Assortative mating increases the production of homozygotes.
95
What is disassortative mating?
Mating of dissimilar individuals
## Footnote
Disassortative mating increases the production of heterozygotes.
96
What is inbreeding?
Mating with relatives
## Footnote
Inbreeding is a common form of non-random mating.
97
What effect does inbreeding have on genotype frequencies?
Increases the frequency of homozygous genotypes compared to random mating
## Footnote
This increase can lead to a higher frequency of recessive genetic disorders.
98
Inbreeding can be a consequence of _______.
assortative mating
99
What does speciation help explain?
The continuity of life and the diversity of life
## Footnote
Speciation links microevolution and macroevolution
100
Why is the classification of species important?
It helps describe and understand patterns of diversity
## Footnote
Species are the units of evolution
101
What defines individuals within a species?
Individuals share an evolutionary trajectory
## Footnote
Different species are evolutionarily independent
102
What is the Morphological (Typological) Species Concept?
A group of individuals that differ from other groups by possessing constant diagnostic characters
## Footnote
Example: 12 different butterflies recognized by their appearance
103
What is a limitation of the Morphological Species Concept?
Seasonal, ontogenetic, environmental or sexual variation can change looks
## Footnote
This makes it challenging to classify species
104
How is the Biological Species Concept defined?
Species are defined by their ability to interbreed, not by physical similarity
## Footnote
Example: Yellow-tailed black and glossy black cockatoos look similar but cannot interbreed
105
What role does gene flow play in the Biological Species Concept?
It holds the gene pool of a species together
106
What characterizes a species according to the Ecological Species Concept?
Its ecological niche
## Footnote
This involves interactions with other organisms and the environment
107
What does the Evolutionary Species Concept emphasize?
A lineage with its own evolutionary tendencies and historical fate
## Footnote
It involves reproductive isolation and applies to fossils
108
What is reproductive isolation?
Biological barriers that prevent interbreeding
## Footnote
It is a driving force behind speciation
109
What are prezygotic barriers?
Barriers that prevent mating or egg fertilization if members of different species mate
## Footnote
They can be premating or postmating
110
What is an example of habitat isolation?
Two species that live in the same area but occupy different habitats rarely encounter each other
111
What is behavioral isolation?
Signals that attract mates are often unique to a species
## Footnote
Example: Different species of fireflies flash different patterns
112
What is temporal isolation?
Individuals must be ready to mate at the same time
113
What is mechanical isolation?
Incompatibility of sexual organs of different species
## Footnote
Example: Genital mismatch in snails
114
What is gametic isolation?
Incompatibility of gametes from different species
## Footnote
Example: Purple and red sea urchins' sperm cannot penetrate each other's eggs
115
What are postzygotic barriers?
Barriers that prevent ongoing gene flow after hybridization occurs
## Footnote
Examples include reduced hybrid viability and fertility
116
What happens in reduced hybrid viability?
First-generation hybrids are aborted as embryos do not survive to maturity
117
What is a characteristic of reduced hybrid fertility?
Hybrids are healthy but cannot reproduce
## Footnote
Example: Mule (donkey x horse) is sterile
118
What is hybrid breakdown?
First-generation hybrids are fertile, but cannot produce fertile offspring in the next generation
## Footnote
Example: 80% drop in fertility in F2 sunflower hybrids
119
What does weak reproductive barriers indicate?
Viable, fertile offspring and potential for gene flow
120
What are limitations of the Biological Species Concept?
1. Not applicable to asexual species
* 2. Difficult to apply to fossils
* 3. Reproductive isolation is often incomplete
* 4. Hard to test reproductive isolation
121
What is a challenge in testing reproductive isolation?
Geographically separated populations complicate how to account for interbreeding
122
What is speciation?
The process whereby a new species arises from an ancestral species, typically requiring reproductive isolation.
123
Why is understanding evolutionary relationships important?
It helps us understand speciation events for a group.
124
What are the two major geographic modes of speciation?
* Allopatric Speciation
* Sympatric Speciation
125
Define Allopatric Speciation
New species are formed in complete geographic isolation from each other.
126
What is an example of Allopatric Speciation?
The formation of the Grand Canyon caused an ancestral population of squirrels to split into two groups that could no longer interbreed.
127
What is the first step in Allopatric Speciation?
Some extrinsic barrier splits a species into two populations and prevents the two groups from mixing and interbreeding.
128
What can cause gene pools to diverge in Allopatric Speciation?
* Genetic drift
* Natural selection
129
What happens if two diverged populations re-encounter each other in Allopatric Speciation?
They may no longer be able to interbreed.
130
Define Sympatric Speciation
Speciation in the complete absence of any geographical barriers to gene flow.
131
What is an example of Sympatric Speciation?
Rhagoletis apple maggot flies arise from within the same geographical area of the ancestral species.
132
What role does sexual selection play in Sympatric Speciation?
It drives diversification and forms barriers that prevent interbreeding.
133
What conditions may lead to Sympatric Speciation?
* Presence of two or more morphs in the population
* Morphs maintained by selection
* Assortative mating leading to reproductive isolation
134
What is Polyploid Speciation?
Speciation driven by chromosomal incompatibilities acting as reproductive barriers.
135
What is an example of a reproductive barrier in Polyploid Speciation?
Different numbers of chromosomes can lead to sterile offspring.
136
Define Allopolyploid speciation
An organism with genomes from different species.
137
Define Autopolyploid speciation
An organism with one genome that has been duplicated.
138
What are Hybrid Zones?
Areas where incomplete barriers exist, challenging the biological species concept.
139
What factors can drive speciation?
* Sexual selection
* Environment
* Ecological interactions
140
True or False: Speciation can occur without geographical barriers.
True.
141
When did Earth form?
4.6 billion years ago
142
What was the early atmosphere of Earth like?
Little oxygen, a 'reducing' atmosphere (electron-adding)
143
What energy sources could have started life on early Earth?
Lightning and UV radiation
144
What is abiotic formation of organic molecules?
Formation of organic molecules (C-H, often O and N) without biological processes
145
What experimental evidence suggests the formation of organic molecules?
Volcanic activity, hydrothermal vents, and meteorites
146
What macromolecules were required for early life?
Proteins, DNA, RNA
147
How can RNA catalyse reactions?
RNA can catalyse reactions without proteins or other catalysts
148
What does the term 'RNA World' refer to?
Self-replicating RNA molecules
149
What process allows for nucleotide polymerization in the RNA world?
Non-enzymatic polymerization
150
What are ribozymes?
RNA strands that perform catalytic functions similar to enzymes
151
What is the significance of protocells?
Abiotic vesicles that can self-assemble and self-replicate
152
What is a major limitation in understanding protocell formation?
Lack of fossil record
153
What role did the environment play in the RNA world?
Certain conditions, like the presence of clay, stimulated vesicle formation
154
What do fossils provide insight into?
The evolution of life over billions of years
155
Where are most fossils found?
In sedimentary rocks like sandstone, mudstone, amber, and frozen soil
156
What are the two main types of fossil dating?
Relative dating and radiometric dating
157
What does relative dating rely on?
The order of layers (strata) in rock
158
What is radiometric dating based on?
The decay of unstable isotopes at a statistically predictable rate
159
What are the four eons of geological time?
Hadean, Archean, Proterozoic, Phanerozoic
160
What significant event occurred 3.5 billion years ago?
The emergence of single-celled prokaryotes
161
What major event occurred 2.7 billion years ago?
The Oxygen Revolution due to photosynthesis
162
What is endosymbiosis?
The process of engulfing bacteria leading to the formation of mitochondria and plastids
163
What are stromatolites?
Layered rocks containing fossilized early prokaryotes
164
What occurred during the Cambrian Explosion?
Most present-day animal phyla appeared suddenly in the fossil record
165
What adaptations appeared in plants around 420 million years ago?
Waxy coating, vascular system, roots, and leaves
166
What is the cause of speciation and extinction rates changing over time?
Catastrophic events and large-scale processes like plate tectonics
167
What is continental drift?
Movement of Earth's crustal plates due to mantle convection
168
What was Pangea?
A supercontinent that existed at the end of the Paleozoic era
169
What are the consequences of continental drift?
* Alteration of physical environment and climate * Promotion of allopatric speciation * Similarities in flora and fauna across continents
170
What percentage of species are estimated to have gone extinct?
98%
171
What caused the Permian mass extinction?
Volcanic activity, ocean warming, and acidification
172
What likely caused the Cretaceous mass extinction?
Asteroid impact and volcanic activity
173
What is adaptive radiation?
The formation of many new species from a single ancestor through adaptation to new niches
174
Is evolution goal-oriented?
No, evolution is not goal-oriented
175
What is a notable trend in the fossil record?
Changes in body size and complexity
176
What does macroevolution involve?
Major evolutionary changes at or above the level of species
177
What are the processes involved in macroevolution?
* Evolutionary stasis
* Speciation
* Extinction
178
What is the purpose of taxa in classification and taxonomy?
Named groups nested at several levels
179
What is Linnaeus' Systema Naturae?
Distinguishes groups but isn't informative about relationships
180
What is the format for binomial species names?
Genus + species, both italicized; Genus has a capital letter, species does not
181
What are strict codes of nomenclature used for?
To remove ambiguity and ensure consistency
182
What is the main benchmark used in modern taxonomy?
Phylogenetics
183
How do shared taxonomic groups reflect evolutionary relationships?
They reflect shared ancestry
184
What do phylogenies represent?
The evolutionary history of species or higher-level groups
185
What do the tips of phylogenetic lines represent?
Extant members of that group
186
What are clades?
Hierarchical groupings or nested groups
187
What is a characteristic of bifurcating trees in phylogenies?
Each branch can only split into 2 branches
188
What do nodes in phylogenies indicate?
Where speciation occurred in the most common ancestor
189
True or False: Phylogenies show patterns of descent.
True
190
What do phylogenies not indicate?
When species arose
191
What defines a monophyletic group?
An ancestor and ALL its descendants
192
What is a paraphyletic group?
A group that does not include all descendants of the common ancestor
193
What do polyphyletic groups often share?
Convergent traits
194
What is homology?
Phenotypic similarity due to shared genetic ancestry
195
What is analogy?
Similarity due to independently evolved features
196
What is the principle of parsimony in building phylogenies?
Trees with the fewest changes are most likely
197
How do you build phylogenies using the principles of parsimony?
* Start with morphological and/or molecular data
* Draw possible phylogenies
* Focus on DNA sequence sites and mark changes
* Repeat for each site
* Determine the tree with the fewest changes
198
What are some applications of phylogeny?
* Taxonomy and classification
* Ecology and evolution
* Medicine
* Crop improvement
* Forensics
199
What is the difference between macroevolution and microevolution?
Macroevolution involves the origin and extinction of lineages; microevolution applies to evolutionary change within a lineage
200
What is the gradualism model?
Evolution is a gradual process with no clear demarcation of species change
201
What is the punctuated equilibrium model?
Long periods of stasis interrupted by rapid bursts of change tied to speciation events
