Evolution Flashcards
evolution
is about changes in populations, species or groups of species.
microevolution
describes the details of how populations of organisms change from generation to generation and how new species originate.
macroevolution
describes the patterns of changes in groups of related species over broad periods of geologic time. the patterns determine phylogeny, the evolutionary relationships among species and groups of species.
Lamarck
on of the earliest advocates for evolutionary ideas. he had three important theories: 1) use and disuse 2) inheritance of acquired characteristics 3) natural transformation of species
Use and disuse
described how body parts of organisms can develop with increased usage, while unused parts weaken.
Inheritance of acquired characteristics
described how body features developed over a lifetime of an organism could be passed along to offspring. this was incorrect
natural transformation of species
described how organisms produced off spring with changes, transforming each subsequent generation into a slightly different form toward some ultimate higher order of complexity. species didnt become extinct. this was incorrect
Darwinism
natural selection or survival of the fittest is the driving force of evolution
Palentology
provides fossils that reveal the prehistoric existence of extinct species. As a result changes in species and the formation of new species can be studied.
Five scientific disciplines that provide evidence for evolution
palentology, biogeography, embryology, comparative anatomy, molecular biology
biogeography
uses geography to describe the distribution of species. this information has revealed that unrealated in different regions of the world look alike when found in similar environments. this provides strong evidence for natural selection.
Embryology
reveals similar stages in development among related species. this similarity helps establish evolutionary relationships (phylogeny)
Comparative anatomy
describes two kinds of structures that contribute to the identification of evolutionary relationships among species.
Homologous structures
are body parts that resemble one another in different species because they have evolved from a common ancestor.
analogous structures
body parts that resemble one another in a different species, not because they have evolved from a common ancestor but because they evolved independently as adaptions to their environment.
Molecular biology
examines the nucleotide and amino acid sequences of DNA and proteins from different species. Closely related species share higher percentages of sequences than species distantly related.
Natural selection
the differences in survival and reproduction among individuals in a population as a result of their interaction with the environment.
Types of fossils
petrification, imprints, molds and casts
petrification
the process in which minerals replace the cells of an organism
imprints
impressions left by an organism (footprints)
molds
form in hollow spaces of rocks as the organisms within decay
casts
formed by minerals deposited in the molds
Comparative Biology
most organisms share the same basic needs and metabolic processes, requiring the same nutrients and forms of energy. The closer the organisms in the evolutionary scheme the greater similarity in their chemical make up and genetic information
Vestigial structures
appear to be useless but had some ancestral function. There are many examples that are similar in organisms. ex. appendix in humans and usage in herbivores
Geographic Barriers
species multiplication is generally accompanied by migration to lessen intraspecific competition. Separation of widely distributed population by emerging barriers increases genetic adaptations.
Systematics
the field if study that constructs and studies evolutionary relationships.
phylogeny
the evolutionary history of a group of organisms. in photogenically relationships the species should be somewhat similar to its ancestors
Cladistics
used to classify organisms based on their phylogenetic relationships. Cladograms are constructed to predict how an ancestor has evolved into its proposed descendents.
clade
each subtree of a cladogram: members of a clade possess some kind of derived characteristics that distinguish them from other clades.
parsimony
the least complex explanation, used by scientist in cladograms
Darwin’s agents leading to evolutionary change
Overpopulation, variations, competition, natural selection, inheritance of the variations, evolution of new species.
Darwin’s theory of overpopulation
more offspring are produced than can survive so there are insufficient resources that can support the entire population
Darwin’s theory of variations
Offspring naturally show differences in their characteristics. De Vries later suggested mutations as the cause. Some are beneficial others are harmful
Darwin’s Competition theory
the developing population must compete for the necessitates of life. Many young must die and adults main constant over generations.
Darwins natural selection/ inheritance theory
The variations some species develop give them advantage over others. since they survives they reproduce “survival of the fittest”. Passing these DNA of sex cells only to offspring
Population genetics
Gene pool of a population is the sum total of all the alleles for any given trait in a population.
Gene frequency is the decimal fraction representing the presence of the allele.
p (dominant) + q (recessive) =1
Hardy-Weinberg Principle
When gene frequencies of a population are not changing the gene pool is stable and the population is not evolving given:
-population is large
-no mutations that affect the gene pool
-mating between individuals is random
-no net migration of individuals in or out
-genes in the population are equally successful at reproducing
yet has absence of microevolutionary change
Hardy- Weinburg equation
p2+2pq+q2= 1
Agents of microevolutionary change
natural selection, mutation, assortive mating, genetic drift and gene flow.
Speciation
is the evolution of new species which are groups of individuals who can interbreed freely with each other but not other species.
Demes
small local population of interbreeding organisms of the same species. they are closely related genetically, since mating between members of the deme occurs frequently. also influenced by the same environmental factors
Adaptive radiation
the emergence of a number of lineages from a single ancestral species. A single species may diverge into a number of distinct species the differences between them are those adaptive to a distinct lifestyle. or niche
convergent evolution
groups on different branches of (phylogeny tree) develop in similar ways when exposed to similar environments.
parallel evolutions
species that develop similar traits though in different geographical areas.
divergent
species that have the same ancestor but bear off into its own species.
