Unit 1 - concepts

Question 1

What is science

Answer 1

An attempt to explain how the universe works

Question 2

Scientific Method

Answer 2

Phenomenon: Something in nature that we wish to explain

Hypotheses: Educated guesses of cause and effect

Theory: Conceptual framework within which our hypotheses are framed (e.g. Newton’s classical mechanics, Mendel’s law of segregation, Darwin’s natural selection)

Predictions: logical deductions of our hypotheses (predictions must be independent of the data or knowledge that went into formulating our hypotheses)

Tests: empirical falsification or verification of our predictions

Question 3

Observability v Repeatability

Answer 3

Observability: The ability to observe what happens as we conduct tests of our hypotheses

Repeatability: This means our tests of hypotheses can be repeated by ourselves, and by others

Question 4

Complexity

Answer 4

Interactions:
“The whole is greater than the sum of its parts” - Aristotle

Whenever the whole is other than the sum of its parts, then we have an interaction. The parts interact non-additively in determining the whole.
examples: interaction among drugs in medicine, genes in determining phenotypic trait, species in community structure

Cause and Effect:

• most effects are affected by more than one cause (example: epistasis in genetics, most traits are affected by multiple interacting genes)
• most causes affect more than one effect (example: pleiotropy in genetics, most genes affect more than one trait)

Feedback Loops:
-most simple cause and effect relationships are bidirectional

Networks:
Consist of a number of nodes with a pattern of connections, edges, among nodes.
Nodes could be neurons, genes, organisms, species; thus, network theory is used to study

Question 5

Integrative Biology

Answer 5

Tinbergen’s 4 Levels of Phenotypic Analysis:

– Causation: mechanisms. An analysis of the physiological mechanisms and environmental mechanisms that give rise to a phenotype. (within organisms)

– Ontogeny: development. An analysis of all of the processes between genes and the environment that go into the development of the phenotype. Includes learning. (within organisms)

– Survival Value: function. An analysis of how natural selection acts on the trait in question. (within populations)

– Evolution: phylogenetic history. For example, do two species share a trait through common ancestry or through convergent evolution? (among populations, among species)

Question 6

Natural Selection - Darwin’s 5 Steps

Answer 6

1. Variation: Individuals vary in appearance (phenotypic variance)
2. Heritability: Some of this variation is passed on from parent to offspring (genetic variance and heritability)
3. Struggle for Existence: Populations produce more offspring than the environment can support
4. Selection (within a generation): Some individuals, due to their phenotypes, have higher survival &/or reproduction than others
5. Evolution (between generations): Those favored phenotypes increase in frequency in the next generation

Question 7

2-Way Interspecific Interactions

Answer 7

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Question 8

Gains and Losses within Levels of Organizations

Answer 8

• Organisms
Energy Input vs Energy Output into Survival and Reproduction

• Populations
Within Subpopulations: Births vs Deaths
Among Subpopulations: Immigration/Colonization vs Emigration/Extinction

• Communities
Immigration/Colonization vs Emigration/Extinction

• Succession
Species replacement over time

• Ecosystems
Within Ecosystems: Energy Cycling: Inputs vs Outputs
Within Ecosystems: Nutrient Cycling: Inputs vs Outputs

• Landscapes
Among Ecosystems: Energy, Nutrients