Honors Biology - Unit 13: Evolution

adaptation

individuals who inherit characteristics that are most fit (suitable/favorable) for their environment are likely to leave more offspring than less fit individuals

adaptive radiation

a number of different species arise from one common ancestor. New environments caused them to evolve differently

allele frequency

how common a certain allele is within a population

analogous structures

similar function, different structure. Evolved similar structure due to living in similar environments, not due to ancestral relatedness. Evidence of convergent evolution

biogeography

where living things are located

Bottleneck Effect

rapid drop in population size which results in a change to the allele frequency

coevolution

two organisms change in response to each other, forming a specialized (symbiotic) relationship

convergent evolution

when unrelated species evolve similar characteristics because they live in similar environments

divergent evolution

when one or more species arise from a common ancestor, and become more and more dissimilar (often caused by differing environments)

speciation

forming of a new species by evolution from pre-existing species. Gene pools gradually become different and are no longer able to reproduce. Some sort of isolation must occur

embryology

the study of the development of embryos across different species, which shows similarities that provide evidence for evolution.

evolution

the process of biological change that makes descendants differ from their ancestors

extinction

the elimination of a species. Can be gradual (slow rate) or mass (catastrophic event changes the environment suddenly)

Founders Effect

when a small population establishes a new settlement, only bringing certain genotypes with it

genetic drift

random change in the frequency of alleles of a population over time. Rare alleles in a population will decrease in frequency, while others will increase. More apparent in smaller populations

Hardy-Weinberg genetic equilibrium

allele frequencies tend to remain the same generation to generation unless acted on by outside influence. Any disruption of ___ will result in evolution

homologous structures

similar characteristics resulting from common ancestry. Same structure, different function, resulting from divergent evolution

macroevolution

evolution on a large scale affecting changes in species across populations

microevolution

evolution can occur on a small scale, affecting a single population

natural selection

some organisms will survive and reproduce better than others, causing changes in the population over time by acting on traits that are heritable; “survival of the fittest”

phenotype frequency

the number of individuals with a certain phenotype divided by the total number of individuals in a population

phylogeny

the evolutionary history of a species or group of organisms

population genetics

the study of evolution from a genetic point of view

relative positioning

the positioning of a point in relation to another point or points commonly for determining spatial relationships

Theory of Evolution

the various types of plants, animals, and other living things on Earth have their origin in other preexisting types and that the distinguishable differences are due to modifications in successive generations

universal ancestor

the hypothesized common ancestral cell from which the three domains of life, Bacteria, Archaea, and Eukarya originated.

vestigial

structures with little or no function to the organism, but are remnants of the structures that had important functions in ancestors of the species. Evidence of divergent evolution

Darwin

an English naturalist who observed adaptations of plants and animals that inhabited diverse environments. Developed the theory of Natural Selection to serve as the mechanism for how evolution occurs

Lamarck

a French naturalist who was among one of the first scientists to realize living things change over time, how species descend from other species, and how species somehow adapt to their environments. Three ideas: Tendency Towards Perfection, Use and Disuse, and Inheritance of Acquired Traits

morphology

the internal and external structure and appearance of an organism

isolating mechanisms

mechanisms or factors which alone or in combination prevent interbreeding between different species/populations and thus prevent gene flow between species

migration

the movement of organisms in or out of a population

artificial selection

an evolutionary process in which humans consciously select for or against particular features in organisms

period

a length or portion of time inside of an era

epoch

a division of time which is a subdivision of a period

gradualism

slow changes over a long period of time

variation

differences in the physical traits of organisms. Exists in every population. May have been inherited and the result of a mutation

directional selection

increases the expression of an extreme version of a trait in a population

stabilizing selection

eliminates extreme expressions of a trait when the average expression leads to higher fitness

disruptive selection

a process that splits a population into two groups; removes individuals with average traits and favors the extremes

punctuated equilibrium

burst of change followed by periods of stability

gene pool

the combined alleles of all individuals in a population

Descent with Modification

a change in gene frequency over time. Beneficial traits should become more common over time

binomial nomenclature

system of classifying organisms using two terms; the first term to define the genus, and the second to define the species

Malthus

developed a theory that plants and animals are capable of producing far more offspring than resources available, creating a “struggle for existence”

Tendency towards Perfection

organisms continue to change and acquire features that help them live more successfully

Use and Disuse

organs in a species appear / disappear as a result of the actions of the organism

Inheritance of Acquired Traits

traits acquired, or gained during an organism’s lifetime can be passed from parents to offspring

gene flow

movement of genes into /out of a population. Occurs during migration, and results in an increase of genetic variability of a population

sexual selection

the selection of traits that are not necessarily good for survival fitness. Without them, you cannot pass on your genes because you are not picked as a mate

prezygotic reproductive barriers

occur before the formation of the zygote. Include habitat isolation, temporal isolation, behavioral isolation, mechanical isolation, and gametic isolation

postzygotic reproductive barriers

after the development of a zygote. Include hybrid offspring fail to reach maturity, hybrids unable to reproduce (ligers), and second-generation hybrid offspring have reduced fitness

allopatric speciation

a population forms a new species while geographically isolated from its parent population

sympatric speciation

populations diverge genetically while sharing a habitat

paleontology

study of prehistoric life. Fossils reveal a history of the types of organisms that lived on Earth and the ages of those fossils

anatomy

study of the structures of organisms

biochemistry

study of the chemical processes in organisms

transitional fossils

link extinct species to current species to help scientists piece together evolutionary history

DNA and protein sequences

comparing similarities in the DNA and amino acid sequences in different species to find common ancestry. Two closely-related organisms will have similar sequences

era

a unit of geological time used to divide an eon into smaller timeframes