Untitled Flashcards Set

Distinguish between sister chromatids and homologous chromosomes

Visualize how meiosis produces four haploid gametes

Calculate the probability of a particular gamete being produced from an individual, assuming independent segregation of alleles

Predict how chromosome numbers in a gamete may vary depending on non-disjunction during meiosis

NDJ in Meiosis 1: 

• 2 gametes have extra chromosomes (n+1)

• 2 gametes are missing chromosomes (n-1)

NDJ in Meiosis 2:

• 1 gamete has an extra chromosome (n+1)

• 1 gamete is missing a chromosome (n-1)

• 2 gametes are regular (n)

Create a pedigree from a scenario

Use pedigree analysis to calculate the likelihood an individual will have a particular genotype or phenotype

To determine the likelihood that an individual has a particular genotype/phenotype, you need to do a punnett square of the genotypes of their parents. If needed, you must also determine the genotypes of the generations before. 

Distinguish between dominant, recessive, autosomal, X-linked patterns of inheritance using pedigrees

Interpret the results of crosses and pedigrees whose results differ from Mendelian expectations because of incomplete dominance, epistasis, or hierarchy of dominance

Analyze VNTR DNA fingerprinting data to determine the genotypes and/or relatedness of individuals

Determine if and where homologous recombination has occurred based on combinations of linked alleles

Calculate genetic map distances among linked genes from the frequencies of progeny with recombinant phenotypes, and construct a genetic map from data provided

Evaluate whether a specific SNP or VNTR is associated with a specific disease

Individuals who are affected are most likely to share the same length VNTRs, which allows us to determine if a VNTR is associated with a specific disease.

Sometimes, due to recombination, VNTRs do not match up with the predicted result. It is important to remember that just because someone has a marker, it doesn’t mean they have the disease.

Compare and contrast the inheritance of germline and somatic mutations

Germline mutations CAN be inherited, and somatic mutations CANNOT be inherited. 

Interpret experiments to determine the relative influences of genes versus the environment on a given phenotype

Evaluate how genes and the environment can interact to influence a phenotype

Complex traits are believed to result from variation within multiple genes and their interaction with behavioral and environmental factors. 

If changes in environment can influence change in phenotype, then it is a complex trait. If changes in the environment have no effect on phenotype, it does not.

Relate trait values of offspring to parents to identify heritability of traits

Calculate allele frequencies based on phenotypic or genotypic data for a population

Calculate genotype frequencies expected under HW equilibrium in a population given its allele frequencies

Recognize the importance of HW equilibrium as a null hypothesis

State whether a population is evolving based on deviations from HW equilibrium

HWE equation

(2 alleles):

• For genotype frequencies: a² + 2ab + a² = 1.0

• For allele frequencies: a + b = 1.0

(3 alleles):

• For genotype frequencies: a² + b² + c² + 2ab + 2ac + 2bc = 1.0

• For allele frequencies: a + b + c = 1.0

The HWE is a null hypothesis that states a population is NOT evolving. 

If expected genotypes differ from observed genotypes, conditions for HWE are NOT met and the population is NOT evolving. If expected allele frequencies differ from observed allele frequencies, the population is NOT evolving. 

Evaluate each assumption of HW equilibrium and the effect violation of the assumptions may have on changing allele frequencies (causing evolution) in a population

The 5 assumptions of HWE:

1. NO natural selection - none of the genotypes is any better than the others at surviving or getting mates. If this is the case, the frequency of A and a alleles in the pool of gametes (sperm and eggs) that meet to make the next generation will be the same as the overall frequency of each allele in the present generation

2. NO assortative mating (random mating is occurring) - we can think of reproduction as the result of two random events: selection of a sperm from the population's gene pool and selection of an egg from the same gene pool. The probability of getting any offspring genotype is just the probability of getting the egg and sperm combo(s) that produce that genotype

3. NO genetic drift (including migration) - Neither individuals nor their gametes (e.g., windborne pollen) enter or exit the population

4. NO mutations - no new alleles are generated by mutation, nor are genes duplicated or deleted.

5. Sufficiently large population size - The population should be effectively infinite in size. This combats/controls genetic drift/random changes in allele frequencies.

Effects of violating the assumptions:

1. Natural selection changes allele frequencies; is an adaptive mechanism

2. Most Assortative mating models do not change allele frequencies but some do. Inbreeding DO NOT CHANGE allele frequencies but can change genotype frequencies

3. Genetic drift allows for less genetic divergence if alleles can come into the population. Certain types of genetic drift events (bottleneck event, colonization/dispersal event) can change allele frequencies by removing certain alleles.

4. Mutations can cause new alleles to occur, and/or can duplicate or delete existing alleles. 

5. The smaller population will also be more susceptible to the effects of genetic drift for generations.

Explain how inbreeding increases the number of homozygotes (and possibly disease) in comparison to HWE.

Differentiate three components of organismal fitness, in the context of natural selection

Three components of organismal fitness:

1. Ability to survive against predators and competition

2. Ability to attract a mate and reproduce

3. Ability to create viable and fertile offspring to continue reproducing and passing down genes

Recognize that selection acts upon individuals, while populations evolve

It takes a long time for populations to evolve. It takes a long time for speciation to occur. Selection acts upon individuals of a population at a given time.

Evaluate data to determine the direction and mode of selection on a specific trait in a population

Predict how different modes of selection affect the distribution of phenotypes in a population

Directional selection favors whatever trait is most fit at that time. Fitness of trait can change over time. Mean trait value follows the curve, meaning most phenotypes in a population follow wherever the curve goes.

Stabilizing population favors intermediates of a trait; the one in the very center are most fit. Most phenotypes will be around the middle trait value.

Disruptive selection favors the extremes. Variations in intermediates are not fit. Distribution of phenotypes will be at the far ends of the range. 

Compare and contrast the mechanisms of natural, sexual, and kin selection.

Define sexual selection (both intra- and intersexual selection).

Define kin selection.

Natural selection - Natural selection is a simple mechanism that causes populations of living things to change over time. In fact, it is so simple that it can be broken down into five basic steps, abbreviated here as VISTA: Variation, Inheritance, Selection, Time and Adaptation.

Sexual selection - A form of selection that promotes traits that increase an individual’s access to reproductive opportunities.

• intrasexual selection: A form of sexual selection involving interactions between individuals of one sex, as when members of one sex compete with one another for access to the other sex. (INTRA = SAME SEX)

• intersexual selection: A form of sexual selection involving interaction between males and females, as when females choose from among males. (INTER = DIFF. SEX)

Kin selection - A form of natural selection that favors the spread of alleles promoting behaviors that help close relatives.

• Based on the idea that helping close relatives will generate genetically similar offspring to future generations if you yourself cannot generate as many by yourself

• Impacts one’s indirect fitness

• Those who practice kinship and have favorable attractive traits are more likely to survive and keep their genes in the gene pool

Define the terms direct, indirect, and inclusive fitness

Direct fitness - The number of offspring an individual procreates

Indirect fitness - The number of offspring an individual’s relative procreates

Inclusive fitness - The combination of direct and indirect fitness; overall fitness

Interpret fitness curves and landscapes to make predictions about the outcome of natural selection over many generations

Relate changes in the environment to changes in a fitness landscape

Describe the mechanisms by which variation arises and is fixed (or lost) in a population over time

Mechanisms that cause variation to arise (changes in allele frequencies)

1. Mutations

2. Gene flow, migration

Natural selection decreases variation. Can cause an allele to become lost over time.

Calculate the relatedness between individuals and how that may influence kin selection and the evolution of certain species’ specific behaviors

Draw arrows. Each arrow represents a 0.50 or 50% relatedness level. 

A parent and their offspring are 50% related.

2 siblings are 50% related.

2 first cousins are 12.5% related.

An offspring to an aunt/uncle is 25% related.

Hamilton’s Rule - supports the notion that natural selection favors genetic success, not reproductive success per se. It recognizes that individuals can pass copies of their genes onto future generations through direct parentage (the rearing of offspring and grand-offspring) as well as indirectly by assisting the reproduction of close relatives (such as nieces and nephews) through altruistic behavior (behavior that benefits other individuals at the expense of the one performing the action).

r₁B - r₂C > 0

“Will B help A?” (refers to beta’s indirect fitness)

r₁ = relatedness of beta to alpha’s offspring

B = the number of MORE offspring ALPHA will have (aka beta’s benefit of helping alpha)

r₂ = relatedness of beta to beta’s offspring (will always be .50)

C = the number of FEWER offspring BETA will have (aka beta’s cost of helping alpha)

“Will A accept help from B?” (refers to alpha’s direct fitness)

r₁ = relatedness of alpha to alpha’s offspring (will always be .50)

B = the number of MORE offspring ALPHA will have

r₂ = relatedness of alpha to beta’s offspring

C = the number of FEWER offspring BETA will have

If the values are greater than 0, the answer is yes. If the value is less than 0, there is no advantage so the answer would be no.

Define the biological species concept.

Recognize the limitations of the biological species concept

Biological species concept - species are groups of actually or potentially interbreeding populations that are reproductively isolated from other such groups. The BSC is the most widely used and accepted definition of a species, but cannot be applied to asexual or extinct organisms.

The major limitations of the biological species concept are that it is irrelevant to allopatric speciation and is inapplicable to: (1) fossil species; (2) organisms reproducing asexually or with extensive self-fertilization; and (3) sexual organisms with open mating systems (species that freely hybridize).

Define the ecological species concept and the phylogenetic species concept.

Ecological species concept - The concept that there is a one-to-one correspondence between a species and its niche.

Phylogenetic species concept - The idea that members of a species all share a common ancestry and a common fate.

Differentiate between pre- and post-zygotic isolating mechanisms.

Relate pre- and post-zygotic isolating mechanisms to the process of speciation.

Prezygotic isolating mechanisms - factors that prevent 2 gametes from coming together and forming a viable zygote. Includes:

• Behavioral: A form of prezygotic isolation in which individuals only mate with other individuals on the basis of specific courtship rituals, songs, and other behaviors.

• Ecological: A form of prezygotic isolation in which individuals are separated on the basis of where they live or what they do in the environment.

• Gametic: A form of prezygotic isolation in which there is incompatibility between the gametes of different individuals.

• Geographic: A form of prezygotic isolation in which individuals are separated in space.

• Mechanical: A form of prezygotic isolation in which individuals are unable to mate, for example, because of structural incompatibility of genitalia.

• Temporal: A form of prezygotic isolation in which individuals are reproductively active at different times.

Postzygotic isolating mechanisms - factors that prevent a zygote from developing into a healthy, viable, and fertile individual.

Once two populations are unable to reproduce and create viable offspring, they can be categorized as 2 separate species. 

Differentiate between allopatric and sympatric speciation.

Describe different models of speciation, with examples.

Four major variants of speciation: allopatric, peripatric, parapatric, and sympatric

Allopatric speciation - speciation that occurs when two populations are geographically isolated from one another.

Sympatric speciation - speciation that occurs when two populations are living in the same geographical location.

Define a population and how a population is distinct from a species. (Discuss the evolutionary significance of this distinction.)

A population can breed with another population if they are the same species. When two populations are isolated, it could lead to speciation.

Recognize that adaptation is not the result of organismal need.

Adaptation occurs over a period of time.

Determine the role of assortative mating, drift, natural selection, and mutation in speciation

Assortative mating - 2 groups that only mate with each other will become genetically different from one another and may diverge into 2 species

Drift - if no drift occurs, the gene pool will become isolated and may lead to speciation

Identify sister and monophyletic groups on a phylogenetic tree.

Define synapomorphy, common ancestor, homologous character, and analogous character

Define the terms synapomorphy, homoplasy, node, sister taxa, monophyletic and paraphyletic group, and phylogenetic tree.

Sister groups/taxa - A group of species that is more closely related to another group of species than to any other group of species

Monophyletic groups - A group of species that all share 1 common ancestor

Paraphyletic groups - A monophyletic group of any size and systematic rank that originated from a single common ancestor, but DOES NOT contain all descendants from this ancestor.

Synapomorphy - derived characters that define a monophyletic group. Exclusive to only that monophyletic group. Not all members of a monophyletic group may have the trait (there can be loss/modification). 

Homoplasy - the development of organs or other bodily structures within different species, which resemble each other and have the same functions, but DID NOT have a common ancestral origin

Common ancestor - the species that existed before it diverged into 2 species

Homologous character - a character found in 2+ groups that was passed down from an ancestor

Analogous character - a character found in 2+ groups that was NOT passed down, but rather was obtained independently

A node represents a branching point from the ancestral population

Phylogenetic tree - a graphical representation of the evolutionary relationships between biological entities, usually sequences or species. Relationships between entities are captured by the topology (branching order) and amount of evolutionary change (branch lengths) between nodes. Are hypotheses, and not definitive reenactments of what occurred in history.

Predict levels of genetic divergence based on relationships illustrated on a phylogenetic tree or proposed scenario

The further away the common ancestor is, the more genetic divergence occurred throughout time. 

Differentiate between the three common representations of phylogenies and correctly interpret the data presented in them

Three types of phylogenies:

1. Cladogram - branch lengths are not specified and have no meaning

2. Phylogram - branch lengths are the expected amount of evolutionary change in the traits used to infer the phylogeny; depicts evolution with amount of genetic divergence

3. Chronogram - where branch lengths are in units of time; depicts evolution throughout time

Interpret patterns of speciation and divergence based on the branching patterns represented on a phylogenetic tree

Vicariance - The process where a geographic barrier arises within a single population, dividing it into 2 populations

• Phylogenetic trees depicting vicariance will have two large groups that are characterized by their location

Dispersal - The process where some individuals colonize a distant place far from the original population

• Phylogenetic trees depicting dispersal will have two large groups that are characterized by their genotype/trait

Use the principle of parsimony to evaluate phylogenetic hypotheses

Parsimony = least number of changes

Predict phylogenetic tree topologies in the presence or absence of convergent evolution

Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups

Converge = think about two groups coming together due to independent evolution

Divergent evolution is commonly defined as what occurs when two groups of the same species evolve different traits within those groups in order to accommodate for differing environmental and social pressures. Various examples of such pressures can include predation, food supplies, and competition for mates.

Diverge = think about two groups going separate ways and having separate traits

Define adaptive radiation. 

Explain how the process of adaptive radiation increases biodiversity.

Evaluate phylogenetic patterns to recognize adaptive radiations within an evolutionary lineage

Adaptive radiation - A period of unusually rapid evolutionary diversification in which natural selection accelerates the rate of speciation within a group, resulting in new species adapted for specific niches. This increases biodiversity by allowing for the rise of new species that are adapted for different specific niches. There is little to no competition between populations. 

How to recognize adaptive radiation in a phylogenetic tree:

1. Common ancestry

2. Rapid diversification at one period of time

3. Trait-environment correlation (the traits the species differentiate in corresponds to the type of environment they live in. e.g. 1 species with short beaks eats seeds, the other species with longer beaks eat fruit)

Explain the role of mass extinctions to diversification after the extinction event.

Explain the relationship between mass extinctions and subsequent diversification.

Mass extinctions lead to diversification and adaptive radiation because now new ecological niches are open for organisms to speciate and fill up those niches. 

By removing so many species from their ecosystems in a short period of time, mass extinctions reduce competition for resources and leave behind many vacant niches, which surviving lineages can evolve into.

Identify the role of fossil evidence and phylogenies to our understanding of evolutionary patterns.

Relate evidence from the fossil record to macroevolutionary changes in major lineages of organisms.

Fossil evidence and phylogenies aid our understanding of evolutionary patterns by making hypotheses about what occurred to these species and organisms throughout time. Fossils serve as a way for humans to see what organisms looked like during their time, and depending on how old it is, we can see changes in evolution.

Recognize major events documenting the appearance of major groups in the evolution of life on Earth

Events include: shifts in landmasses (Pangea, Gondwana, Laurasia, etc.), mass extinctions, etc. 

Determine the age of a fossil based on 14C dating.

Living organisms—like trees, plants, people, and animals—absorb carbon-14 into their tissue. When they die, the carbon-14 starts to change into other atoms over time. Scientists can estimate how long the organism has been dead by counting the remaining carbon-14 atoms.

When the organism dies, carbon-14 is no longer being absorbed into the tissue, so scientists can compare the amount of carbon in the fossil to living organisms to determine its age. Less carbon-14  means an older organism.

Carbon-14 dating is only useful for fossils younger than 50,000 to 60,000 years old.

Evaluate data and phylogenetic patterns, and indicate how they are used to test hypotheses about historic and current patterns of biodiversity.

Data and phylogenetic patterns are used to test hypotheses about historic and current patterns of biodiversity by giving us insight into how organisms change and why. 

Interpret a chronogram and draw conclusions from the data

Chronograms depict change over time. Shorter branch = occurred more recently, longer branch = occurred more later

Relate data from molecular clocks to evolutionary patterns in organismal lineages

Molecular clocks show us the rate of mutations of certain biomolecules (like genes, proteins, etc.). Can be used to deduce the time in prehistory when two or more life forms diverged. Typically when we want to know how many genetic differences two groups have, we need to determine how long ago the 2 groups diverged and add up the rates of mutation for each of them. 

Compare and contrast long-term versus short-term carbon cycling

Carbon cycling: The network of biological and physical processes that shuttles carbon among rocks, soil, oceans, air, and organisms.

Long term carbon cycling: The cycle of carbon through a long period of time; examples include burning fossil fuels

Short term carbon cycling: The cycle of carbon through a short period of time; examples include photosynthesis, cellular respiration, seasonality

Explain what information is exhibited in a survivorship curve

A survivorship curve is a graph showing the number or proportion of individuals surviving to each age for a given species or group

Type 1 - Late death in time

Type 2 - Constant rate of death

Type 3 - Early death in life

Differentiate between r- and K-strategists

Evaluate the relationship between life-history strategies and population growth.

K-selected species are those that are larger, have long lifespans, produce few young at a time, and exhibit logistic growth.

• K for kangaroo

R-selected species are those that have shorter lifespans, are generally smaller, produce many young, and exhibit exponential growth.

• R for roach

Life history strategies are a term to describe the way in which an organism divides its resources and energy between its own survival and growth and the survival of its offspring (reproduction). In simpler terms, a life history strategy is a way an organism makes trade-offs between survival and reproduction.

K-strategists have a slow population growth because they put more energy towards raising few young & ensuring they survive close to reproductive age.

R-strategists have a fast population growth because they put more energy towards having multiple offspring to ensure a large number of their offspring have the opportunity to live.

Define metapopulation

Describe characteristics of a metapopulation (source and sink populations, colonization, dispersal)

A large population made up of smaller populations linked by migration.

Source populations - mainlands, where species come from; can sustain itself; birth is greater than death so it produces a lot of dispersals 

• If the growth rate is larger than 1, the habitat or population is considered to be a source, otherwise it is deemed to be a sink

Sink populations - habitats in which populations cannot survive when they are isolated from other populations; cannot sustain itself; death rate greater than birth rate

Colonization - when a (group of) organisms starts a population in a habitat that was not previously inhabited 

Dispersal - moving from one place to another 

• Successful dispersal allows the colonization of new habitats and territories

Relate the Law of Tolerance to species’ distributions

A law stating that a certain organism’s survival and existence depend upon the multifaceted set of conditions wherein each individual has definite minimum, maximum and optimum ecological factors to establish success.

Species will distribute themselves to places where they will have the highest levels of success/fitness.

Define ecology, and understand how abiotic and biotic interactions drive pattern and process at different organizational levels (individuals to ecosystems).

Ecology: The study of how organisms interact with one another and with their physical environment

Abiotic factors can directly affect the survival of species in an ecosystem by creating or altering the conditions necessary for their survival. 

Biotic factors include interactions between organisms, like disease, predation, parasitism, and competition among species or within a single species. 

Predict how resource limitations force life-history trade offs

Life History: The typical pattern of resource investment in each stage of a given species' lifetime.

• r-selected organisms - put most of their energy into rapid growth and reproduction. This is common in organisms that occupy unpredictable environments, e.g. weeds are usually annuals with rapid growth and early reproduction. They produce large number of seeds containing few stored nutrients

• K-selected organisms - put most of their energy into growth. They are common in stable environments near carrying capacity, e.g. long lived trees such as redwoods take many years of growth to reach reproductive age

Life history strategies depend on available resources. Some species can vary their strategy depending on the environment. Sometimes it can be more effective to have less eggs with more nutrients or more eggs with less nutrients. There are many trade offs including energy, time, resources, space, etc.

Each individual must devote some of its available food and energy intake to growth, some to the maintenance of cells and tissues, and some to reproduction (lots of tradeoffs)

Identify factors influencing population growth, and carrying capacity

Biotic examples:

• Crowding

• Disease/sickness

• Competition

Abiotic examples:

• Natural disasters

• Climate change

Explain why exponential population growth is unsustainable

Exponential growth is not a very sustainable state of affairs, since it depends on infinite amounts of resources (which tend not to exist in the real world). Exponential growth may happen for a while, if there are few individuals and many resources

Evaluate the role of density dependence in regulating population growth

Density-dependent factors include disease, competition, and predation. Density-dependant factors can have either a positive or a negative correlation to population size. With a positive relationship, these limiting factors increase with the size of the population and limit growth as population size increases

Classify the types of interspecific interactions between species

Predict the effects of interspecific interactions on the abundance for species involved in the interaction

Discuss the importance of competition, predation, and symbiotic relationships (i.e., mutualism, commensalism, parasitism) in structuring natural communities.

Predation: +/-

Herbivory: +/- 

Parasitism: +/-

• Abundance can increase or decrease depending on the species and how it is effected

• Positively affected species may increase, while negatively may decrease

• Can often lead to oscillations (often seen in predator-prey models)

Mutualism: +/+

• Abundance can increase

Commensalism: +/0

• Abundance can stay the same

Competition: -/-

• Abundance can decrease

These interspecific interactions are important in structuring natural communities because each species in a community plays a role in how the ecosystem runs. 

Differentiate between fundamental and realized niche

Explain how biotic factors determine the distinction between fundamental and realized niches

Explain how biotic factors determine the distinction between fundamental and realized niches.

Fundamental niche: the niche that a species could potentially fill

Realized niche: the niche a species actually fills

Biotic factors can alter realized niches and are the basis of fundamental niches. 

Explain energy flow in food webs and how this gives rise to biomass pyramids

Draw a food chain and recognize how energy is transferred between each level

Predict changes in biomass in trophic levels between top-down and bottom-up control

10% of energy is transferred between the pyramid levels. The rest of the energy is released as heat.

Recognize the causes and impacts of inefficient energy transfer

Reasons why energy transfer is inefficient:

• Not all the organisms at a lower trophic level get eaten by those at a higher trophic level

• Some molecules in the bodies of organisms that do get eaten are not digestible by predators and are lost in the predators' feces (poop). The dead organisms and feces become dinner for decomposers

• Of the energy-carrying molecules that do get absorbed by predators, some are used in cellular respiration (instead of being stored as biomass)

• Energy is released as heat

Impacts of inefficient energy transfer:

• Fewer organisms at the top of the pyramid because there is not enough energy for them to have a large population size

Explain how diversity can affect primary productivity

Recognize the diversity of consumer-resource interactions and their effects on populations

Diversity can affect primary productivity depending on the interspecies interaction:

Invasive organisms can reduce primary productivity.

Articulate how interspecific competition can lead to coexistence and/or competitive exclusion, and predict how competition influences species distributions

Interspecific competition can lead to coexistence, but the fitness of both species will decline. The realized niche of these species will also decrease, as they are unable to occupy a larger niche in comparison to when they exist alone. 

Interspecific competition can lead to competitive exclusion if one species is better at competing than the other. We see this with invasive species, as they exclude species and prevent them from growing. 

Competition can influence species distributions through niche partitioning. Niche partitioning is when 2 species begin to use different resources (although their fundamental niche states they can use the same resources) in order to both have a chance of survival. Competition can influence distributions as well when worse competitors decide to move to an area their competition cannot occupy (like in a rocky area). 

Define functional redundancy in the context of an ecosystem

Predict the effects of redundancy on an ecosystem

Functional redundancy is the phenomenon that multiple species representing a taxonomic group can share similar roles in ecological functionality.

Functionally redundant ecosystems are more resilient to change.

Diverse ecosystems are functionally redundant, and therefore more resilient.

Biodiversity leads to ecological resilience!

Justify how the loss of species may impact ecosystems

Loss of species makes ecosystem more vulnerable to disturbance, it it will have less resilience and it cannot recover quickly from disturbance

Top-Down control: when a species at the top of the ecosystem declines, which has a cascading effect that will impact the rest of the food chain.

Bottom-Up control: when primary producers at the bottom declines, the rest of the food chain population declines. 

Loss of keystone species can lead to a disruption in the ecosystem, leading to its demise.

Define a community and recognize communities exist at a range of scales

Describe how community assembly is driven by colonization, competition, and extinction

An ecological community is defined as a group of species that are commonly found together. Communities exist at a range of scales, with some having large numbers of species, some having small, some having lots of diversity, and some having few.

Relate species’ interactions in and between communities to the carbon cycle.

Autotrophs capture carbon dioxide from the air or bicarbonate ions from the water and use them to make organic compounds such as glucose.

Heterotrophs, or other-feeders, such as humans, consume the organic molecules, and the organic carbon is passed through food chains and webs. Carbon dioxide is released as these organisms break down food (cellular respiration).

Decomposers also release organic compounds and carbon dioxide when they break down dead organisms and waste products.

Describe how the distribution of global biodiversity is influenced by solar radiation and air circulation patterns

Solar Radiation:

Because the Earth is closer to the sun at the equator, there is more solar energy and primary productivity at the equator. This means more biodiversity.

Air circulation patterns:

Air circulation patterns dictate climate. Long-term climate stability at the equator allows organisms to thrive because there are no abiotic factors limiting growth.

Explain why vegetation is the most commonly used proxy to characterize terrestrial biodiversity

Vegetation consists of primary producers, which are the basis of the ecological food chain. When there are more primary producers, there will be more species supported in the ecosystem, therefore it is often used to approximate the biodiversity of a system. 

Evaluate the evidence for anthropogenic climate change and how it relates to the long-term vs. short-term carbon cycles

Describe anticipated effects of climate change on the distribution and evolution of biodiversity

Species response to global climate changes:

• Migration to more favorable places

• Adapt to changes

• Lose abundance or become locally extinct

Identify common threats to biodiversity

Threats to biodiversity:

• Over-exploitation of resources (over-harvesting)

• Habitat loss

• Climate change

• Redistribution of biodiversity 

  • Invasive species

  • Disease ecology

Differentiate between species diversity and species richness

Species richness: how many DIFFERENT species there is

Species evenness: how many INDIVIDUALS in EACH DIFFERENT species

Species diversity: a combination of richness and evenness

• High richness + high evenness = high diversity

Define ecosystem services

Ecosystem Services are the direct and indirect contributions ecosystems (known as natural capital) provide for human wellbeing and quality of life. This can be in a practical sense, providing food and water and regulating the climate, as well as cultural aspects such as reducing stress and anxiety.

Evaluate data on the effects of alterations to biogeochemical cycles

A biogeochemical cycle, or more generally a cycle of matter, is the movement and transformation of chemical elements and compounds between living organisms, the atmosphere, and the Earth's crust. Major biogeochemical cycles include the carbon cycle, the nitrogen cycle and the water cycle.

Relate species diversity on islands to rates of colonization and extinction

Predict general patterns of species diversity on islands

Arrival rate of new species decreases as species accumulate because there is no more space available for them to colonize.

Extinction rate increases as individuals from different species compete for resources.

Eventually, arrival and extinction rates balance each other at a point of equilibrium (S)

ΔS = C - E

ΔS = C(S) - E(S)

Far islands have lower colonization rates compared to near islands

Extinction rates are not influenced by distance from source populations

Larger islands have more colonists and lower rates of extinction compared to smaller islands

Highest species diversity is found in large, close islands.

Describe traits commonly exhibited by invasive species and their effects on native flora and fauna

Invasive species: species introduced to new areas can be considered invasive if they have negative impacts on native species

Introductions via: natural colonization, human-transported for aesthetics, agriculture, hunting, species control, erosion control, and accidental

Characteristics of invasive species: competes strongly w/ natives, no predators/disease in new location, can alter ecosystem, may push natives to extinction

Evaluate the effects of over-exploitation on the evolution of life history

Over-exploitation of organisms can lead to disruptions in ecosystems and can damage the overall health of a system.

Relate climate warming to changes in phenology, and how changing phenology of one species can affect the ecology of other species

Phenology: recurring plant and animal life cycle stages and their timing and relationships with weather and climate; nature’s calendar 

Climate warming can impact phenology and cause changes in behavior such as mating times, hatching times, migration times, etc.