BIOL 286: Lecture #1 Review (Introduction to Ecology and Evolution)

ecology

The study of the relationships between living organisms

How do scientists study ecological interactions? (5)

(1) observation studies; (2) genetics and genomics; (3) laboratory studies; (4) studies in the field; (5) mesocosm and microcosm experiments

Types of ecology: (4)

(1) individual; (2) population; (3) community; (4) ecosystem

individual ecology

can examine interactions between an individual and the environment (e.g. behavior of the individual

population ecology

examines the interactions among a population and the interaction of the population and the environment (e.g. population genetics

community ecology

interactions between multiple populations in one particular area or environment (e.g. study the diversity and evenness of communities

ecosystem ecology

interactions between the ecological community and the abiotic environment; might involve studying nutrient cycling or thermodynamics

evolution

refers to the scientific fact that biological organisms have changed through time

Evolution refers to . . .

the genetic change in a population over time

Ecology and evolution are . . .

intricately interconnected

proximate causes of evolution

direct/immediate causes of evolution; the mechanism precipitating evolutionary change

Specify the proximate cause of evolution. Case: A change in snowshoe hare coat color.

Photoperiod initiates molting

ultimate cause of evolution

evolutionary factors that led to the adaptation

Specify the ultimate cause of evolution. Case: A change in snowshoe hare coat color.

Selective pressures from predation

adaptation

a trait or characteristic of an organism (e.g. coat color in hares

fitness

the survival and reproduction of an individual

Ways of measuring fitness: (4)

(1) life span; (2) reproductive age; (3) number of clutches (batch of offspring); (4) clutch size or number of offspring produced

habitat

where an organism lives

niche

the summary of an organism's tolerances or reuqirements of the abiotic environment; also account for interactions with other species

Abiotic factors can include: (5)

(1) temperature; (2) pH (water

Principles of evolution by natural selection: (4)

(1) Populations contain variation; (2) Some of this variation is heritable; (3) All populations have the potential to undergo exponential growth

Evolution by natural selection: Variation

Variation means that individuals in a population are not identical. Rather

Evolution by natural selection: Heredity

Heredity refers to the principle that some variation in traits is passed from parents to offspring via genetic transmission. Only heritable variation can contribute to evolutionary change

Evolution by natural selection: Differential reproduction

Differential reproduction is the principle that individuals with certain traits produce more surviving offspring than others. Because not all offspring live to reproduce

Evolution does not . . .; that is

organisms do not . . .

Organisms with a beneficial phenotype for a particular environment are . . . This . . .

more likely to survive and reproduce; increases the frequecy of those beneficial alleles/genotypes over time in the population

When discussing evolution

we may examine either . . . or . . .

When examining evolution over long time scales

we are typically investigating . . .

When examining evolution over short time scales

we are typically investigating . . .

fossils

preserved remains of once living organisms

Concerning fossilization

. . . are more likely to be preserved

Why does fossilization rarely occur?

Fossilization is uncommon because it requires a very specific chain of events. Most organisms decompose

Fossilization occurs when . . .

there is rapid burial of an individual (organism covered in sediments)

Soft body parts typically only fossilize . . .

in anoxic conditions

fossil record

the record of the occurrence and evolution of living organisms through geological time as inferred from fossils

homologous structures

shared structures across different species inherited from a common ancestor

Explain how homologous structures provide support for evolution.

Homologous structures demonstrate that different species inherited the same underlying anatomical features from a common ancestor. Even when contemporary structures serve distinct purposes (e.g. a bat's wing

homoplasy

a characteristic shared by a set of species but not present in their common ancestor

Homoplasy may be produced by . . .

convergent evolution

convergent evolution

the independent evolution of similar features in different lineages; similar evolutionary pressures can result in similar traits or body plans

Phenotypes converge when . . .; in other words

convergent evolution . . .

analogous structures

features in different species that perform similar functions but do not share a common evolutionary origin

Steps of the scientific method: (5)

(1) observation; (2) hypothesis; (3) measurements; (4) results; (5) conclusion

Hypotheses include . . .

a testable mechanism

Distinguish between hypotheses and predictions.

A hypothesis includes a testable mechanism by which a posited outcome occurs. By contrast