1
Q
What are genes?
A
The fundamental unit of heredity
2
Q
What is genetics?
A
The study of genes, genetic variation, and heredity in organisms
3
Q
What is a genotype?
A
- The genetic makeup of an organism
- Also used to describe a single gene or set of genes that determine the organism’s phenotype
4
Q
What is a phenotype?
A
The observable characteristics or traits of an organism
5
Q
Are all traits controlled by more than one gene?
A
Yes!
- All traits are controlled by multiple genes
- Some traits have predominantly one gene governing their expression, others have many
6
Q
Are traits only genetically determined?
A
No.
- Some traits are strongly genetically determined
- Others have a stronger environmental influence
7
Q
What is a recent example of genes and the environment affecting phenotype?
A
- Autism Spectrum Disorders (ASD)
- Studies have found that certain genetic mutations + early life infections can lead to symptoms of ASD later in life
8
Q
What genetic principles account for passing of traits from parents to offspring?
A
- Blending Hypothesis: Genetic material from two parents blends together
- Particulate Hypothesis: Parents can pass on discrete heritable units (this explains reappearance of traits after several generations)
9
Q
What did Gregor Mendel do, in a nutshell? When did he live?
A
- Mendel used the scientific method with pea plants to study inheritance
- 1822-1884
10
Q
What are some of the advantages to using pea plants to study inheritance?
A
- Available in many varieties, which have distinct heritable features/characters (each variant for a character is a trait)
- Short generation time
- Large number of offspring from each mating
- Mating could be controlled
11
Q
What are the pollen-producing organs in the pea plant flowers?
A
Stamens
12
Q
What are the egg-bearing organs in the pea plant flowers?
A
Carpel
13
Q
What are the three components of a carpel?
A
Stigma (receptive tip), style, ovary
14
Q
How do pea plants fertilize?
A
- Pea plants usually self-fertilize: sperm released from pollen grains from the stamen land on the carpel of the same flower and fertilize eggs.
- They also can be cross-pollinated
15
Q
What are the two components of a stamen?
A
Anther, filament
16
Q
What happens when true-breeding plants self fertilize?
A
They produce offspring with the same phenotype (ex. purple parent –> all purple flowers)
17
Q
What was the first cross Mendel did?
A
Mendel cross pollinated two contrasting, true-breeding pea plants.
18
Q
What is the cross-breeding of two true-breeding plants called?
A
Hybridization
19
Q
In Mendel’s pea plant experiment, what are the true-breeding parents called?
A
The P-generation
20
Q
In Mendel’s pea plant experiment, what are the hybrid off-spring of the P-generation called?
A
F1 generation
21
Q
What results when F1 offspring self or cross pollinate with another F1 hybrid?
A
F2 generation
22
Q
Explain what happened in the F1 and F2 generations of Mendel crossing a white and purple parent plant.
A
F1 - All purple
F2 - 3:1 purple:white
23
Q
What is ecology?
A
- The scientific study of interactions between organisms and the environment
- Includes biotic and abiotic interactions
24
Q
What are some examples of biotic factors?
A
- Predators/prey
- Conspecifics
- Mutualism
- Parasitism
25
What are some examples of abiotic factors?
- Temperature
- Water and moisture
- Geology and substrates
- Weather and climate
26
Who coined the term "ecology"?
Ernst Haekel in 1866, refining it in 1869
27
Who defined ecology as the "study of interactions that determines the distribution and abundance of organisms"? When?
Andrewartha and Birch, 1953.
28
Who defined ecology as the "study of broad-scale ecosystems mechanics; considering the flow of biomass and energy"? When?
Odum, 1971
29
What is not ecology?
- Simple natural history
- Environmentalism or activism
- Eco-tourism
- Sustainable farming, fishing, or hunting
They aren't ecology because they lack the scientific method and **math**!
30
What drives the formation of biomes?
Biotic and abiotic interactions
31
What are the primary abiotic factors that shape an environment?
Temperature & moisture
32
What is the relationship between ecological interactions and evolutionary change?
- Ecological interactions (change) alters selective pressure in populations, causing evolutionary change
- Evolutionary change alters outcomes of ecological interactions
Ecological interactions can cause evolutionary change (and vice versa)!
33
What do ecologists do?
They study interactions between organisms and their environments at various levels of the biological hierarchy - from individual organisms to the biosphere.
34
What happens in the larger scales of ecological organization?
Integration of biotic aspects of community structure with broad-scale abiotic factors
35
What happens in community ecology (broadly)
Predation, interspecific competion, succession, etc.
36
What happens in population ecology? (broadly)
Intraspecific competition, life history strategies
37
What does autocology study?
Individuals (behaviour, diet, physiology)
38
What types of scales do we use to approach the complexity of ecology?
- Fine scale controlled lab experiments
- Small to medium scale controlled field manipulations
- Small to large scale field observations
- Historical studies (paleoecology)
Temporal and spatial scales must be carefully selected based on the questions being asked and organisms involved
39
What is organismal ecology?
Organismal ecology studies how organisms' structure, physiology, and behavior meet environmental challenges
- includes physiological, evolutionary, and behavioural ecology
40
What can happen when organisms meet environmental challenges?
They can respond with changes in physiology, behaviour, or evolutionary adaptations
41
What is the law of toleration?
Distribution and abundance of species depends on deviation between local conditions and optimal conditions for species
42
What is the niche?
The set of resources and conditions under which an organisms can survive and reproduce
- Hutchinson (1957) defined niche as *n-dimensional hypervolume*, where *n* equals the number of environmental factors important to survival and reproduction of a species
43
What is competitive exclusion?
- Proposes that two species which compete for the same limited resource cannot coexist
44
In competitive exclusion, what happens when one species has an advantage over the other?
- When one species has an advantage, the other one will be outcompeted in the long term
- This leads to either extinction of the weaker competitor or some form of adaptive change
45
What facilitates coexistence of species?
Niche segregation
46
What would happen if species all stuck to their fundamental niche?
* They would overlap and compete more
* Competion has forced the narrowing from fundamental to realized niche
47
What is population ecology?
Population ecology focuses on factors affecting population size over time
48
What is a population?
A group of individuals of the same species, in the same area, and capable of interbreeding
49
What is population size?
A product of increases and decreases
50
What is growth rate?
Births + immigration - deaths - emigration
51
What are limiting factors?
- The resources and environmental conditions that affect the growth of a population.
- Biotic and abiotic
52
What is the home range?
The area in which an animal lives and moves around within on periodic basis
53
What is the species range?
The geographic area over which all the individuals of that species live.
54
What is dispersal?
The movement of individuals away from centers of high population density or from their area of origin
55
What is community ecology?
- Community ecology examines the effect of interspecific interactions of community structure and organization
56
What is a community?
A group of populations of different species in an area
57
What are interspecific interactions (symbiosis)
Relationships between species in a community
58
What is competition?
Occurs when individuals of different species vie for limited resources
59
How can scientists examine competition?
Scientists can study ecological niches, compare the degree of niche overlap and competitive ability, and determine the likelihood of competitive exclusion.
60
What is a fundamental niche?
Niche potentially occupied by a species
61
What is the realized niche?
Portion of fundamental niche actually occupied by a species
62
What is predation?
When one species (predator) kills and eats the other (prey)
63
What is herbiovory?
When one organism eats part of a plant or alga
- There are many vertebrates examples, but most are invertebrates
64
What is parasitism?
- When one organism (parasite) derives its nourishment from another organism (host)
- Parasites can significantly affect the survival and reproduction of their host
65
What is an endoparasite?
Parasite that lives within the body of their host
66
What is an ectoparasite?
A parasite live on the external surface of the host
67
What is mutualism?
- This interaction benefits both species
- Can be obligate (one species cannot live without the other) or facultative (both species can survive alone)
68
What is commensalism?
When one species benefits and the other species is neither helped nor harmed
69
What is ecosystem ecology?
The integrated study of biotic and abiotic components of an ecosystem and the communities within
70
What is an ecosystem?
All the organisms and the physical environment with which they interact
71
What is landscape ecology?
Landscape ecology focuses on the factors controlling exchanges of energy, materials, and organisms across multiple ecosystems
72
What is a landscape (or seascape)?
A mosaic of interconnected ecosystems
73
What is global ecology?
Global ecology examines the influence of energy and materials on organisms across the biosphere
74
What is the biosphere?
Sum of all of the planet's ecosystems
75
Where do archaea live?
Most habitats on Earth, including most extreme environments
76
When were archaea considered seperate from bacteria? What was originally thought about archaea?
1977. Originally thought to be rare and only in extreme
environments, but they are diverse, abundant, and can be
found almost everywhere
77
Why is little known about archaea?
They are very difficult to grow in the lab, and it's difficult to sample their environments since equipment is very expensive and logistics are complicated.
78
What similarities in anatomy do bacteria and archaea have?
- Single celled
- No nucleus or organelles
- DNA in the form of single circular chromosome (and plasmids)
79
What similarities in reproduction and genetic diversity do archaea and bacteria have?
- Binary fission
- Horitzontal gene transfer
- Transformation
- Transduction
- Conjugation
80
How do archaea get nutrition?
Can be both autrophs (produce their own food) or heterotrophs (get food from other sources)
81
What similarities do archaea have to eukarya?
Similarities in DNA replication and organization, and protein synthesis
82
What makes archaea unique from eukarya and bacteria?
Ability to live in extreme environments
83
What are extremophiles?
Organisms that exist in extreme conditions that most life cannot tolerate
84
Why are archaea thought to be similar to the earliest life on Earth?
Because early life on earth would've experienced the harsh conditions where archaea thrive, such as:
- Little to no oxygen
- Extremely hot
- Acidic and toxic chemicals present
85
What are acidophiles?
Organisms that can grow in high acidic conditions (pH < 3)
86
What's an example of an archaea that is an acidophile?
ARMAN archaea: thought to be the closest known relative to the common ancestor of all life - discovered in 2006 in acidic mine drainage in California
87
What are halophiles?
Organisms that can grow in extremely salty conditions, way saltier than the ocean
88
What's an example of archaea that is a halophile?
Haloarchaea: autotrophic archaea that contains a bright pink pigment and thrive in salty water
89
What are thermophiles?
Organisms that can grow in extremely high temperatures ( > 100 degrees Celsius)
90
What's an example of an archaea that is a thermophile?
Sulfulobus: autotrophic archaea that grow in hot volcanic springs
91
What is methanogenesis?
- A form of anaerobic respiration that produces methane gas (CH4) as a waste and is only performed by some Archaea (methanogens)
- Occurs deep in the water and in the digestive tracts of animals
92
Is the most extreme organism on Earth in the domain Archaea?
NO!
93
What are tardigrades?
- Micro-animals
- Mostly microscopic
- Can go decades without food/water (suspend their metabolism - cryptobiosis)
- Can withstand really high pressure and temperature extremes (-272 to +151 C)
94
What are protists?
- "The simplest definition is that protists are all the eukaryotic organisms that are not animals, plants, or fungi"
- Not a distinct lineage
- A diverse collection of mostly unicellular eukaryotes
- More structural and functional diversity than other eukaryotes
- Very complex (ex. all biological functions carried out by a single cell in unicellular protists)
95
Where do they (protists) fall on the tree of life?
- The organisms in most eukaryotic lineages are protists
96
What is an example of a eukaryotic protist?
Forams - unicellular; marine; pseudopod structures (fake arms vibes)
97
What is an example of a protist in the domain archaea?
Ciliates - unicellular organisms; hair life structures; found anywhere there is water; long, stringy, weird
98
What is an example of a protist in the domain bacteria?
Amoebas - unicellular; can change shape; move via pseudopods
99
Are protists their own kingdom?
- No
- Used to be
- Because of genetic discoveries and similarities between eukaryotes, we reclassified them into super groups
- Protists are polyphyletic (classified into the same group but come from different ancestors)
100
How many supergroups of protist classficiations are there?
6
101
How do protists get their nutrition?
Most nutritionally diverse of all eukaryotes
- Photoautotrophs (plant-like protists)
- Heterotrophs (animal-life protists)
- Mixotrophs (not seen in any other domain) (use a combination of autotrophy and heterotrophy)
102
How do protists reproduce
- Mostly binary fission
- Some protists reproduce sexually under stressful conditions
103
What is the benefit to protists reproducing sexually in stressful conditions?
- Increase genetic variation
- Hoping for mutations to help survive changes in environment
104
How are protists important primary produces?
- Protists use the energy in sunlight to build organic molecules that accumulate in the form of biomass
- Really important for the bottom of the food web
105
How are diatoms important primary producers?
- Diatoms are unicellular algae with a unique two-part, glass-like wall of **silcon dioxide**
- A major component of phyto-plankton
- Fossilized diatom walls compose much of the sediments known as diatomaceous earth
106
How are dinoflagellates important primary producers?
- Dinoflagellates are unicellular organisms with two flagella
- Abundant components of phyto-plankton
- Can trigger toxic "red tides"
107
What is an example of a pathogenic protist?
Plasmodium - genus of parasitic protists that cause the disease Malaria
Transmitted to humans by female mosquitos
Feed on red blood cells, causing fever, fatigue, vomiting, and more extreme in severe cases
108
What is evolution?
- Descent with modification
- More specifically, a change in gene frequency within a population over many generations that confers a fitness advantage
109
What was Aristotle's theory on evolution?
- He saw species as fixed, unchanging
- Life forms could be arranged on a ladder of increasing complexity
- *Scala naturae*
- 384-322 BCE
110
What were Carolus Linnaeus' thoughts around evolution?
- He sought to classify life's diversity "for the greater glory of God", grouping organisms similar based on pattern of their creation
- Plants and animals were different
- Similar things could be grouped
- 1707-1778
111
Who was Erasmus Darwin and what were his thoughts on evolution?
- He published first formal theories of evolution = Zoonomia
- Grandfather to Charles Darwin
- Lacked a strong testable framework, but set the tone
- 1731-1802
112
Who was James Hutton and what were his thoughts on Evolution?
- Father of Modern Geology
- He proposed the principle of gradualism
- Change occurs gradually
- The Earth underwent continuing transformation over long periods of time
- 1726-1797
113
Who was Georges Cuvier and what were his thoughts on evolution?
- Largely developed paleontology, the study of fossils
- Put forward that fossils are remains or traces of organisms from the past
- Believed in catastrophism, the idea that Earth has been shaped by sudden, short-lived events
- 1769-1832
114
Who was Charles Lyell and what were his thoughts on evolution?
- Authored Principles of Geology and proposed the principle of uniformitarianism:
- Earth's geologic features could be explained by gradual mechanisms and geological events occur at the same rate now as they have always done
- He also visited Joggins Fossil Cliffs in Nova Scotia
- Discovered, with William Dawson, *Hylonomus lyelli*, the earliest unquestionable reptile
- 1797-1875
115
Who was Mary Anning and what were her contributions to early evolution
- She was a fossil collector, dealer and palaeontologist, who significantly advanced our understanding of extinction and changing diversity
- Much of her work and effort was overlooked until long after her passing
- 1799-1847
116
Who was Thomas Malthus and what were his thoughts on evolution?
- He was an English economist
- Wrote "Essay on the Principle of Population
- Populations cannot grow forever
- Populations will always outgrow the food supply
117
Who was Jean Baptiste Lamarck?
- He was a French naturalist, biologist, academic, and soldier
- The first to propose a mechanism for how life changes over time
- Two principles :
- Use and disuse: body parts that are used extensively become larger and stronger, while those that are not used deteriorate
-**Inheritance of acquired characteristics**: an organism could pass these modifications to its offspring
118
What was Jean Baptiste Lamarck's hypothesis for Inheritance of Acquired Characteristics?
Inheritance of acquired characteristics is based on use or disuse of features. He reasoned the giraffe's neck was a result of continued use, same as the stocky musculature of blacksmiths
119
Was Jean Baptiste Lamarck's hypothesis correct?
- No
- Although generally wrong as an encompassing process, the idea it has now resurfaced in the field of epigenetics!
120
What is epigenetics?
Modification of gene expression rather than an alteration of the genetic code itself (a change in DNA function, not sequence)
121
What is DNA methylation?
- Methyl groups are added to the DNA
- Represses gene expression
122
What is DNA acetylation?
Induces higher levels of transcription
123
What is histone modification? What does this mean for genes?
Posttranslational modifications on histones (can lead to active or repressed genes)
124
What are microRNA?
Non-coding RNA that can bind to mRNA and prevent its translation
125
Who was Charles Darwin, and what did he do for evolution?
- Lifelong naturalist, failed medical doctor, almost clergyman
- Widely credited with devising the theory of evolution
- He not only recognized that species changed through time, but also described how evolution occurred - through the process of natural selection
126
When did Darwin leave on the HMS Beagle, and for how long?
1831, for 9 years
127
What are the Galápagos Islands?
- A group of volcanic islands near the equator, ~900km west of Ecuador
- Most species not known from anywhere else in the world
- Darwin hypothesized that the Galápagos Islands had been colonized by organisms that had strayed from South America and then diversified, giving rise to new species on the various islands
128
What did Darwin's discover from observing the Galápagos finches?
- Darwin proposed that, through natural selection, an ancestral species is to give rise to two or more descendant species
- This might happen if one population is fragmented into several subpopulations isolated in different environments (under different selective pressure)
- One species radiates into many species as the populations adapt over many generations to different sets of environmental factors
- **ADAPTIVE RADIATION**
129
What else did Darwin observe from the finches?
- Individuals in a population vary in their traits
- Environments vary across a landscape
- Resources are unequal
- A population can produce far more offspring than can survive to produce offspring of their own
- Species are well-suited to their environment
130
What did Darwin **conclude** after his observations?
- Individuals with inherited traits that are better suited to the local environment are more likely to survive and reproduce than less-well-suited individuals
- Over many generations, a higher and higher proportion of individuals in a population will have the advantageous traits
- Evolution occurs as the unequal reproductive success of individuals ulitmately leads to adaptation to their environment
131
What are the two main points articulated in *On the Origin of Species*?
- Contemporary species arose from a succession of ancestors that differed from them = "descent with modification"
- Natural selection is the primary cause of descent with modification
132
What is natural selection?
The process by which individuals within a population possess certain traits, and by having these traits tend to survive and reproduce more often
133
Who was Alfred Russel Wallace and what was his role in evolution research?
- He was an English naturalist, explorer, geographer, biologist, and illustrator
- He independently conceived the theory of evolution through natural selection
- "The Father of Biogeography"
- He dramatically advanced our understanding geographic features that delineate faunal communites
134
Does evolution always take place over millions of years?
No!
- Darwin's ideas of evolution require "deep time" (millions of years), but we know it can happen in far more observable timelscales
135
What are the three conditions required for evolution by natural selection suggested by Darwin?
1. Vairation in a trait must exist between individuals in a population
2. Traits must be, at least partially, heritable
3. Traits must confer differential outcomes relating to fitness and that fitness is not random, but rather the result of the difference in an organism's traits
136
What are the four different lines of evidence that support evolution?
1. Homology
2. Direct observations
3. The fossil record
4. Biogeography
137
What is homology?
- Similarity (in structure, function, genetics, or development) of different species because of descent from common ancestry
- Characteristics present in an ancestral organism can be altered by natural selection in its descendants - but they share an origin
- As a result, **related species can have similar characteristics, yet functions can vary**
138
What are homologous structures?
Structures that are similar in **structure** because of common ancestry, but **not necessarily in function**
139
What are analogous structures?
Structures that are similar in **function**, but with a **different evolutionary origin**
140
What are vestigial structures?
Remnants of features that served a function in the organism's ancestors
141
What are some examples of vestigial structures?
- Goosebumps on your skin
- Appendix
- Wisdom teeth
- Eye remnants under the scales of blind cave fish
- etc
142
What are conserved physiological processes?
Similar pathways and responses because of common ancestry
143
What are conserved and repeating genes?
Homologous genes, organisms with a common ancestor share some genes (molecular homologies)
144
What are pseudogenes?
Genes that remain in the genome but have lost at least some functionality
145
What does high overlap of similarity between DNA sequences and the pseudogene mean?
It means that it is highly likely that these two sequences diverged from a common ancestor
146
What are some shared features of all chordates?
1. Notochord
2. Pharyngeal slits
3. Endostyle (or thyroid gland)
4. Dorsal hollow nerve cord
5. Post-anal tail
147
What are some ways we have been able to see evolutionary processes at work?
- Natural selection in response to introduced plant species
- Evolution of drug-resistant bacteria
- Natural selection for heritable behaviour in urbanized lizards
148
Which type of dragons were the boldest; natural, semi-natural, or urban?
Dragons from origin populations in human-modified landscapes were bolded
- This suggests natural selection has caused evolution for more risk-taking dragons
149
What are fossils?
- Remains or traces of organisms from the past
- Found in sedimentary rock which appears in layers of strata
150
What kinds of organisms are most likely to be preserved in fossils?
Those who:
- Lived where sediments were disposed
- Died in anoxic conditions
- Had mineralized body parts
- Were present in great numbers
151
What sorts of evidence does the fossil record provide?
Provides evidence of:
- The origin of new species
- The extinction of species
- Changes over time
- A physical history of how life has evolved over billions of years
- Can help determine relationships between modern and ancient groups
152
What is Tiktaalik?
A fossil in the transition from **water to land**
- Had gills and lived in shallow water, where its appendages would have helped it crawl through mud and lunge at prey
153
What is Archaeopteryx?
A transitional fossil between dinosaurs and birds
154
What is Ambulocetus?
A transitional fossil between land mammals and whales
- Amphibious cetacean, often called a "walking whale"
- Ecologically it had a role much like modern crocodilians
155
What is biogeography?
- The study of the geographic distribution of species
156
How does Pangea and continental drift impact where we find fossils?
It allows us to make predictions, based on this former positioning of continents, on where similar living and fossilize species should be found
157
What are endemic species?
Species that are not found anywhere else in the world
158
Where are most endemic species found?
On islands
159
What is biological fitness?
The ability to survive to reproductive age, find a mate, and produce offspring
- Survival of the "fittest"
160
What is directional selection?
A mode of natural selection that pushes a population in one direction
161
What is disruptive selection?
A mode of natural selection that pushes a population in two directions
162
What is stabilizing selection?
A mode of natural selection that maintains the norm
163
Can individuals evolve?
No, individuals do not evolve, rather populations evolve over time
164
What type of traits can natural selection affect?
Heritable traits
165
What determines which traits are favoured?
It depends on the environment - a trait that is favourable in one place or time may be useless or detrimental in another
166
Does natural selection increase fitness?
Yes
167
Does natural selection increase or decrease genetic variation?
Natural selection alone decreases genetic variation
168
What can all mechanisms of evolution do?
Change the frequency of alleles that produce certain traits
169
What is artificial selection?
- The selective breeding of plants and animals to encourage the occurrence of desired traits
- Over time this can lead to domestication
- Results in organisms that are significantly different from their wild counterparts
170
What is genetic drift?
-Changes allele frequencies across generations due to **chance events** (random impacts)
- Occurs more clearly in small populations
- Can increase or decrease fitness
- Tends to reduce genetic variation, and thus push evolution in a certain direction
171
What is the bottleneck effect?
- Where a sudden change in the environment can drastically reduce the size of a population
- By **chance** alone, **certain alleles may be over-represented, under-represented, or absent among the survivors**
172
What is the founder effect?
- When a few individuals become isolated from a larger population, the smaller group may establish a new population whose gene pool differs from the original population (often far reduced in size)
173
What is gene flow?
- Transfer of alleles into or out of a population
- Related to movement and connectivity
- Tends to increase genetic variation
- Can increase or decrease fitness
174
What are mutations?
- Change in one or several genes that can be transmitted to subsequent generations
- Can increase genetic variation
- Can increase or decrease fitness
175
What is human-driven climate change?
- Greenhouse gas effect, associated with human practices increasing the amount of carbon in the atmosphere
- Movement of carbon that was sequestered either underground or withing biotic forms is now released
- Result in more solar heat being absorbed across the globe
- We are the cause and the solution (if we act appropriately)
176
Who was Eunice Foot?
She formed the first of the greenhouse effect (1856)
177
Who was Svante Arrhenius?
He did calculations about how much CO2 it would take to make a meaningful shift in climate (1895) - won a Nobel Prize
178
Who was Francis Molena?
Published a four-page article about climate change in Popular Mechanics (1911)
179
What are the Big 5 mass extinctions?
- End Ordovician
- Late Devonian
- End Permian
- End Triassic
- End Cretaceous
180
What is humanity's goldilocks zone?
- Where our Earth has been existing the last while
- "Just right"
- Scary to leave because we have it pretty good right now
- Could mess up agriculture
181
What sorts of things can climate change impact?
- Physical environment
- Primary production
- Biodiversity
- Biotic interactions
182
What are the most critical drivers that delineate habitat types?
Temperature and precipitation
- This creates mismatches with the range of tolerances and alters the components of the niche
183
What would happen to terrestial vertebrates with a 4.4C increase and no action?
40% will be exposed to extreme heat frequencies, durations, and intensities
184
Why would reptiles and amphibians be most affected by climate change?
More vulnerable because they live in smaller temperatures ranges
185
What else can heat stress cause?
Dramatic die-offs that can wipe out entire ecosystems
186
What happens when climate change shifts an environment?
- Results in an evolutionary mismatch
- Niches change and species are pushed beyond their range of tolerances
- In short: when the environment changes, many species no longer fit within it
187
What is Gross Primary Productivity (GPP)?
- The total amount of chemical energy produced by a photosynthetic life in an ecosystem for a given period
- Plant traits are both responsive to climate and strong predictors of primary productivity
188
On a global scale, at current rates in GPP increasing or decreasing?
Climate change will decrease global GPP by 8%
189
What are some ways more energy being brought in can impact natural disasters?
Extreme events such as heatwaves, polar vortexes, flooding, etc. become more likely
190
How can climate change effect cells?
- Many biochemical reactions occur at an optimum temperature
- Temperature increases affect enzyme activity
191
What is climate change's impact on individuals?
Homeostasis can be affected with climate change. This can impact:
- Daily activity levels
- Seasonal activity levels
- Reproduction
- Growth and development
Can be seen in both endothermic and ectothermic organisms
192
How can climate change affect populations?
- As individuals incur challenges from climate change; resulting in an evolutionary mismatch between their biology/ecology and the environment we can see the effect scale up to the population level
- Populations can increase or decrease as some species adapt (or not) to the changing climate
- **If the impact affects a large number of individuals then we see population effects**
193
How can climate change impact communities?
- Climate change can lead to species moving in new locations, causing dramatic changes in ecological communities
- Some species will be able to adapt and persist under climate change scenatios, but if they rely on food webs or ecosystem that contains more sensitive species then the deletion of species can destabilize the balance
194
What is a population?
- A localized group of individuals capable of interbreeding and producing fertile offspring
- There can be different populations of the same species
195
True or false: a genetic change at a single locus is not enough to cause genetic change
**FALSE** populations CAN evolve with genetic changes at a single locus
196
What is allele frequency?
The relative frequency of an allele at a particular locus in a population
197
Which allele does *p* represent?
Allele frequency of dominant trait
198
Which allele does *q* represent?
Allele frequency of recessive trait
199
What do the frequency of all alleles in a population add up to?
1
- That's *p* + *q* = 1
200
What's the formula for genotype frequency?
Genotype frequency = (number of individuals with a particular genotype in a population) / (total number of individuals in the population)
201
Do allele and genotype frequencies change when no evolution is occurring?
No, in a population that is not evolving, the allele and genotype frequencies will remain constant from generation to generation
= Hardy-Weinberg equillibrium
202
What is the Hardy-Weinberg equillibrium?
- A principle that describes a hypothetical population that is not evolving
- In real populations, allele and genotype frequencies do change over time
203
What are the 5 conditions for HW equillibrium?
These are very rarely met in nature:
1. No mutations
2. Random mating
3. No natural selection
4. Extremely large population size
5. No gene flow
204
What does the Hardy-Weingberg Principle state?
- Allele frequencies in a population will not change from generation to generation
- If the allele frequencies in a population with two alleles at a locus are p and q, then the expected genotype frequencies are p^2, 2pq, q^2
- p^2 + 2pq + q^2 = 1
205
What is the equation for allele frequency?
p + q = 1
206
What is the equation for genotype frequency?
p^2 + 2pq + q^2 = 1
207
What are some qualities of bacteria?
- Single-celled
- Among the first life forms on Earth
- A large domain of prokaryotic microorganisms
- Present in most habitats on Earth
- Not just disease causing pathogens
208
What are the different shapes of bacteria?
- Spherical (cocci)
- Rod-shaped (bacilli)
- Spiral-shaped (spirochetes)
209
What does the cell wall do?
- Maintains shape
- Protects the cell
- Prevents it from busting
- Compostion can be classified using gram stain
210
What makes a bacteria gram-positive?
- Large amounts of peptidoglycan
211
What is peptidoglycan?
- Polymer consisting of sugars and amino acids that forms a mesh-like layer outside the plasma membrane
- Target of many antibiotics
212
What makes a bacteria gram-negative?
- Less peptidoglycan and an outer layer of lipopolysaccharides that can be toxic
- More likely to be antibiotic resistant
213
What colour is gram positive? What colour is gram negative?
- Positive: violet
- Negative: red
214
What is a capsule?
A capsule (of polysaccharides or proteins) can be located immediately exterior to the peptidoglycan layer of gram-positive bacteria and the outer lipopolysaccharide layer of gram negative DNA
215
Why is the capsule important?
- Anti-phagocytic
- Protects cells from desiccation
- Helps cells adhere to surfaces
- Protect anaerobes from oxygen toxicity
- Protexts bacteria from viruses
216
What are fimbriae?
- Some bacteria stick to their substrate or to one another by hair-like appendages called fimbriae
- Fimbriae can be used by bacteria to form biofilm
217
What are pili?
- Appendages that pull two cells together to allow DNA transfer from one cell to another
218
What is the flagella?
- Enables movement toward or away from a stimulus
- Can be scattered over entire cell or concentrated at one or both ends
219
What are specialized membranes in bacteria?
- Some bacteria have specialized membranes that perform metabolic functions
220
How much DNA do bacteria have?
- Less DNA than eukaryotes
- Mostly a single, circular chrosome (in nucleoid region)
- Some species also have smaller circular DNA molecules - plasmids
221
What three factors contribute to bacteria's considerable genetic variation?
1. Rapid reproduction
2. Mutation
3. Genetic recombination
222
How do bacteria repoduce? How long does it take?
- Asexually through binary fission
- As little as 10 minutes
223
How do mutations affect bacteria?
- Mutation during binary fission is low, but because of rapid reproduction, mutations can accumulate rapidly in a population
224
What is genetic recombination?
- Combining of DNA from two sources - contributes to diversity
- Movement of genetic material between organisms = horizontal (or lateral) gene transfer
- DNA from different bacteria can be brought together by transformation, transduction, and conjugation
225
What is transformation?
Where foreign DNA is take up from the surrounding environment and incorporated into a cell
226
What is transduction?
Bacteriophages carry prokaryotic genes from one host cell to another
227
What is conjugation?
- DNA is transferred between two bacteria (usually of the same species) that are temporarily joined via a sex pilus
228
What is nitrogen fixation?
A process in which some bacteria convert atmospheric nitrogen to ammonia - this nitrogen can then be incorporated into organic molecules in plants
229
About how many of all human diseases are cause by bacteria?
Half
230
True or False: some bacterial infections may lead to stronger immunity in offspring
True
231
What is a virus?
An infectious, obligate intracellular parasite comprised of genetic material (DNA or RNA) surrounded by a protein coat (and sometimes a membrane)
232
What does obligate internal parasite mean?
Viruses only replicate in host cells
233
What are some qualities of viruses?
- Sub-microscopic (light)
- Obligate intracellular parasites
- Absolutely depend on host cell for ATP, amino acids, nucleotides, etc
- Do not grow or divide
- Do not have ribosomes (or genetic info to make them)
- Do not have metabolic pathways
234
Are viruses alive?
No, they do not fulfull all the characteristics of living things
235
How many viruses are there estimated to be on Earth?
10^31
236
Who used tobacco plants to demonstrate how viruses are transferred?
Martinus Beijerinck
237
Why can't viruses be cultivated in test tubes?
They require a host to replicate
238
What are the components of a virus?
They consist of nucleic acid surrounded by a protein coat called a capsid, and sometimes a viral envelope
239
What does the capsid do?
Encloses the viral genome; made of protein subunits called capsomeres
240
What are adenoviruses used for?
To deliver genetic material to target cells
241
How does SARS CoV-2 work?
SARS CoV-2 virions use glycoproteins to bind to ACE-2 receptors on the surface of a variatey of cells
242
What is the life cycle of a virus?
- Infect a host
- Replicate
- Ensure that progeny are transmitted
243
What is a retrovirus?
A virus that inserts a DNA copy of its RNA genome into the DNA of the host cell that it invades, changing the genome of that cell.
244
What is the lytic cycle?
A reproductive mechanism or phages - produces new phages and lyses the host
245
What is the lysogenic cycle?
A reproductive mechanism of phages that produces new phages without destroying the host
246
What happens if viruses shuffle their genes in host cells?
Could result in more of less pathogenic variants
247
What four concepts explain the 3:1inheritance pattern?
1. Alternative versions of genes account for variations in inherited characters (= alleles!)
2. For each character, an organism in herits two copies (alleles) of a gene, one from each parent
3. If two alleles at a locus differ, then one, the dominant allele, determines the organisms appearance; the other, the recessive allele, has no noticeable effect on the organism's appearance
4. The two alleles for a heirtable character segregate during gamete formation an end up in different gametes (law of segregation)
248
What is the Law of Segregation?
- The two alleles for a heritable character segregate during gamete formation and end up in different gametes
- Segregation of alleles corresponds to distribution of homologous chromosomes to different gametes in meiosis
- Egg or a sperm gets only one of two alleles
249
What does homozygous mean?
Two identical alleles
250
What does heterozygous mean?
Two different alleles
251
What is a testcross?
Breeding an organism of unknown genotype with a recessive homozygote to determine its genotype
252
What are monohybrids?
F1 offspring that are heterozygous for one character
253
What are dihybrids?
F1 offspring that are heteroygous for two characters
254
What was a dihybrid cross used to determine?
If two characters are transmitted as a package or independently
255
What is the Law of Independent Assortment?
- **Each pair** of alleles segregates independently of each **other pair** during gamete formation
256
What is the phenotypic ration of a dihybrid cross?
9:3:3:1
257
What is gene linkage?
How genes located near each other on the same chromosome tend to be inherited together
258
When might inheritance of characters by a single gene deviate from simple Mendelian patterns?
- When alleles are not completely dominant or recessive
- When a gene has more than two alleles
- When a gene produces multiple phenotypes (called pleiotropy)
259
What is complete dominance?
- When phenotypes of the heterozygote and dominant homozygote are identical
- The dominant allele will mask the recessive allele when in a heterozygous state
260
What is incomplete dominance?
- Where the phenotype of F1 hybrids is in between the phenotypes of the two parental varieties
- For example, think red and white flowers crossing to give pink
- Not blending! F2 generation shows the alleles for red and white are still present
261
What is codominance?
Two dominant alleles affect the phenotype in seperate, distinguishable ways
- For example, type AB blood
262
What is a sex-linked gene?
A gene located on either sex chromosome
263
What is a Y-linked gene?
- Genes on Y chromosomes
- Dominant and recessive traits do not apply to Y-linked traits because only one allele is present
264
What are X-linked genes?
- Genes on X chromosomes
- X-linked dominant inheritance: only one copy of the allele is required in both sexes
- X-linked recessive: only one copy is required in males; females need two copies
265
Are X-linked recessive disorders more common in males or females?
Males
266
What is a pedigree?
- A family tree describing interrelationships of parents and children across generations
- Traces and describes inheritance patterns of particular traits
267
Can the environment play a role in determining phenotype?
Yes
268
What is phenotypic plasticity?
The ability of one genotype to produce more than one phenotype when exposed to different environment
BIOL1001
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