Exam 1 Flashcards
Compare pure & applied ecology.
-Pure ecology: also known as basic or fundamental ecology, is the study of ecological principles and processes without immediate concern for practical applications.
Applied ecology: focuses on using ecological knowledge and principles to address practical problems related to environmental management, conservation, and sustainability.
How does evolution explain the differences and similarities between organisms?
Common Ancestry: Explains similarities due to shared evolutionary history and differences due to divergent evolution.
Natural Selection: Leads to similarities in traits due to adaptation to similar environments and differences due to adaptation to different environments.
Genetic Variation and Mutation: Accounts for the raw material of evolution, leading to both similarities (shared genetic functions) and differences (mutations and adaptations).
Adaptation and Convergence: Results in similar traits in different lineages due to similar selective pressures, and diverse traits due to adaptations to different environments.
Evolutionary Relationships: Reveals both similarities (shared traits from common ancestry) and differences (divergent evolution) among organisms through phylogenetics.
What evidence exists in support of the theory of evolution?
-Historic record
-Ancient and modern organisms share traits
-organisms change over time
-Another evidence is an antibiotic can evolve resistance to extremely high concentrations in a short period of time
How is evolution linked to an organism’s phenotype? Genotype?
Phenotype: Observable traits influenced by both genetic and environmental factors. Evolution acts on phenotypes by selecting for traits that enhance survival and reproduction.
Genotype: The genetic makeup of an organism that underlies the phenotype. Evolution involves changes in genotype through mechanisms like mutation, recombination, and gene flow, leading to changes in phenotype over time.
Define unitary & modular organisms, give an example of each.
unitary: vertical inheritance, one body (such as humans)
modular: horizontal growth (such as plants, fungi, microorganisms, sponges, corals)
Compare mutation, genetic drift, gene flow, and natural selection with regards to effects on genetic variation and population divergence
mutation: errors occurring DNA replication = new allele. It generally increases genetic variation and increases population divergence
gene flow: increases genetic variation and decreases population divergence
natural selection: can reduce but cannot add genetic variation. It increases population divergence
genetic drift: generally reduces genetic variation and increases population divergence
Describe the three steps or requirements for evolution by natural selection. Be able to give two examples of natural selection resulting in species or population evolution.
- mutations exist
- mutations linked to differential reproduction
- mutations heritable
( 2 examples: peppered moths and darwins finches)
Peppered moths:: During the Industrial Revolution, soot darkened tree trunks, making light-colored moths more visible to predators. Dark-colored moths had better camouflage and survival.
Darwin finches: On the Galápagos Islands, finches evolved different beak sizes based on available food resources—large beaks for hard seeds and small beaks for insects.
Contrast directional, disruptive and stabilizing selection and recognize each from descriptions or graphs of changes in population allele frequencies
Directional: conditions favor individuals at one extreme of phenotype range. Shifts population towards one extreme
Disruptive: conditions favor individuals at both extremes of phenotype range, not intermediates. Shifts population towards both extremes
stabilizing: Conditions favor intermediate phenotypes, extremes are disadvantaged. Shifts population towards middle and restricts it there.
How do frequency-dependent and sexual selection maintain genetic diversity within a population?
frequency dependent: fitness depends on the frequency of allele in a population ex. bank voles
sexual selection: some individuals more likely to obtain males, those genotypes increase in the next generation ex. peacock tails
What is the biological species definition and what are its limitations?
- A group of organisms that can interbreed and produce fertile offspring, and which are reproductively isolated from other such groups.
lim:
- fossil “species” are extinct
- some species hybridize- gene flow
- many species reproduce asexually
Compare allopatric and sympatric speciation. Give an example of each.
allopatric: New species form due to geographic separation. ex. Darwin’s finches on different islands
sympatric: New species form within the same area. ex: Cichlid Fish in the same lake but with different niches.
Compare punctuated equilibria and gradual change models of evolution.
Punctuated equilibria: brief time of rapid change, then stable
Gradual change(most support this): constant small changes throughout time
Define adaptive radiation and link it to extinction and speciation.
adaptive radiation: one species gives rise to many new species that exploit different environmental features- Food or habitats.
Extinction: Creates opportunities for adaptive radiation by removing competitors and freeing up niches.
Speciation: The process of adaptive radiation results in the creation of many new species from a common ancestor.
Distinguish between clines and ecotypes.
clines: measurable, gradual change over region in average of phenotype or trait due to environmental gradients
ecotypes: population adapted to it’s local environment
Define developmental plasticity and acclimation.
developmental plasticity: irreversible phenotype changes during organism development
Acclimation: reversible phenotype changes in response to changing environment conditions during organism’s lifespan
Why does variation persist in populations? Why are species not perfect in every respect?
Variation persists in populations due to continuous genetic changes, environmental pressures, and mechanisms like genetic drift and gene flow. Species are not perfect because evolutionary processes are constrained by trade-offs, historical contingencies, adaptive lags, environmental variability, and genetic limitations. Evolution promotes adaptation to current environments rather than achieving perfection.
Describe two perspectives on value of biodiversity.
Ecological Perspective: Emphasizes the importance of biodiversity for ecosystem health, stability, and the maintenance of ecosystem services.
Utilitarian Perspective: Focuses on the direct economic, practical, and cultural benefits of biodiversity for human use and development.
How many species are currently estimated to exist on Earth? List several reasons why this estimation is difficult and in-accurate.
About 3-5 million species worldwide
How is species richness different from species evenness in a community? Why do ecologists measure both?
Species Richness: Counts the number of different species in a community.
Species Evenness: Measures how evenly individuals are distributed among those species.
What is a rank abundance curve? What two things can it imply about a community?
Rank Abundance Curve: A plot showing the relative abundance of species ranked by their abundance.
Species Evenness: Indicates how equally individuals are distributed among species (flatter curves suggest higher evenness).
Species Richness: Reflects the number of species present (longer curves suggest higher richness).
What is a species-area curve? Give three reasons why this relationship exists.
is a graphical representation that shows the relationship between the area of a habitat or environment and the number of species it supports. Generally, the curve demonstrates that larger areas tend to support more species.
Reasons:
1.Larger habitats offer more diverse ecological niches.
2.Bigger areas provide more resources and reduce extinction risk.
3.Greater area supports more colonization and potential for speciation.
Explain differences between conditions and resources.
Conditions are the environmental factors that affect organisms but are not consumed or used up by them. They describe the physical and chemical state of the environment.
Resources are environmental elements that are consumed or used by organisms to survive, grow, and reproduce. They are essential for the organisms’ energy and material needs.
Which two laws of thermodynamics relate to ecosystem ecology & energetics?
-First Law of Thermodynamics: Energy conservation—energy flows through ecosystems, being transformed but never created or destroyed.
-Second Law of Thermodynamics: Energy transfer is inefficient—energy is lost as heat, leading to decreased efficiency and increased entropy with each transfer between trophic levels.
Given equations, calculate the energy flow through a tropic level including assimilation efficiency, production efficiency, consumption efficiency and trophic efficiency.
do a problem
