Flashcards in Week 1 Deck (19):
What is an emergent property? Provide examples.
It's the property where living things become more and more complex as it goes from cellular level (humans are made of cells) to organ system (humans are made of organ system composed of millions of cells).
What levels of the hierarchy are typically involved in ecological studies?
Organismal Ecology - interactions between individuals and their environment (physiological/behavioral ecology); Community Ecology - interactions among coexisting species; Ecosystem Ecology - interactions between ecological communities and their abiotic environment; Population Ecology - dynamics of a group of individuals of a single species (population genetics, demography); Ecosphere/Biosphere - sum of all Earth's ecosystems
What are the steps of the scientific method? Why can they be applied to questions addressing adaptations or natural selection?
Question, Hypothesize, Experiment, Observe/Record, Analyze, Share Results
What distinguishes scientific hypothesis from scientific theory?
Scientific theory is an explanation of a set of related events based upon hypotheses supported multiple times.
What is the difference between proximate and ultimate levels of causation? Provide examples of each.
Proximate factors = direct or immediate causes of biological processes/phenomena; Ultimate Factors = deeper cause of a phenomenon that explains why it occurs. Example: Proximate cause of wing color is genetic in peppered moths; Ultimate cause of wing color is to help the moths blend in - moths that have wings of the same color as the trees are more likely to survive. OR proximate causes = direct effects of external stimuli - snowshoe hare color changing color based on temperature and photoperiod vs. ultimate causes = evolutionary factors - selective pressures from predation
How do Tinbergen's inform our understanding of proximate and ultimate levels of causation?
Proximate view = How an individual organism's structure functions?
Ultimate view = Why a species evolved the structures it has?
The changes that have occured in the horse lineage over 60 million years constitute macroevolutionary changes. How do these relate to microevolutionary changes?
Microevolutionary changes include changes in allele frequencies within the population over time, short term evolutionary changes. Macroevolutionary changes include great phenotypic changes, classify changed lineage + descendants to distinct genus/higher taxon.
What factors influence how rapidly different organisms may evolve?
(1) Rates of environmental change organisms experience; (2) Amount of genetic variation within species; (3) Size of population; (4) Generation time of population
What contributions did Charles Darwin make to our understanding of biological diversity?
Observations: variability of life forms, similarities suggesting relatedness; Logical Arguments: heritable variation within species (passing traits on), prodigious (large) reproductive potential of organisms, intense competition among organisms; Conclusions: concept of evolution by natural selection; Mechanisms: individuals with inherited traits that increase fitness will increase in frequency in populations relative to other competing individuals
What is the unit of evolution (what evolves)?
Population - a group of interbreeding individuals of the same species in the same geographic location
What is the relationship between genetic information flow and evolution? How are genes related to evolution?
Gene flow = net movement of alleles to and from a population; Evolution proceeds by changes in the genetic composition of a population
What factors are responsible for producing a phenotype?
Genotype + Environment -- Development --> Phenotype
What is natural selection?
Differential survival and/or reproduction of entities that differ in 1 or more characteristics
Why can evolution occur with or without selection?
Evolution can occur due to genetic drift (random changes in allele frequencies), gene flow (the net movement of alleles to/from a population), mutation pressure (changes in allele frequencies due to the origin of new alleles in the population)
What is an adaptation? Why are adaptations not necessarily adaptive across time or environments?
Trait that increases an individual's fitness in a SPECIFIC environment
What is fitness? Why is fitness a relative measure?
Fitness is the survival and reproduction of a particular individual as determined by its characteristics. It is a relative measure because the fitness of an individual in a population is compared to other individuals in a population who may have different phenotypes.
What does it take for a trait to evolve by natural selection (i.e. prerequisites)? Why is each important? For any trait, explain how each of the prerequisites must be met in order for that trait to have evolved by natural selection.
Prereq's for NS: (1) Phenotypic variation in population; (2) Differential survival and/or reproductive success associated with certain phenotypes; (3) Individual capacity to overproduce is limited by environmental resources (Malthusian Parameter); (4) Trait heritability.
What is heritability and why is it important for natural selection to act on a trait? What is one simple way to estimate heritability?
Heritability is the proportion of variance among individuals in a trait that is attributable to differences in genotype, it is also the degree of trait resemblance between parents and their offspring; it can be estimated by regression slope. The higher the heritability the tighter the genetic control of development. The rate of evolution depends on the intensity of selection and heritability of the trait.