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30 Cards in this Set

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  • Back
the separation (splitting) of a lineage. This results when populations w/in a species become reproductively isolated and then diverge until they no longer can iterbreed
a taxon or other group consisting of an ancestral species and all of its descendents, forming a distinct branch of a phylogenetic tree
Adaptive radiation
a diversification that produces many different lineages from a single ancestral lineage, producing a cluster of related species during a fairly short period of time
The THEORY OF NATURAL SELECTION has 3 point, what are they?
1) Variation
2) Heritability
3) Overproduction of offspring leads to a struggle for existence
Members of a species vary w/respect to specific traits; e.g., light vs. dark fur; long vs. short legs; big vs. small body size
These variable traits are heritable. In other words, they have a genetic basis and so they are passed from parent to offspring
Overproduction of offspring leads to a struggle for existence
In population, typically more offspring are produced than can survive long enough to reproduce themselves (b/c the resources necessary for survival & reproduction, such as food, water, space, usually are limited). Since there are not enough resources to support everyone, the various members of the population compete for the resources necessary to stay alive & to have their own offspring
The THEORY OF NATURAL SELECTIONS 3 points lead to this?
"Variation in fitness (survival & reproductive success) causes evolution to occur." Since there is a struggle for existence & b/c individuals very in theri traits, the individuals w/the traits that are best suited to the local environment survive & reproduce, and they contribute a disproportionately large number of offspring to the next generation. Since these beneficial traits have a genetic basis. a large proportion of the next generation now carries that beneficial trait as well. Bit by bit, generation after generation, the genetic structure of the population changes. In other words, evolution has occurred...
any genetic change, and resulting phenotypic change, in a lineage (i.e., line of descent) from generation to generation
Who proposed the concept of "uniformitarianism" and what does it mean?
Charles Lyell. This theory states that the same physical processes active in the environment today have been operating throughout the life of the planet. Thus, processes we see at work today - such as erosion & deposition by wind & water, periodic geological events such as volcanoes & earthquakes - are the same processes that have shaped the overall landscape throughout the planet's history. **A KEY POINT to note is that these geological processes take a long, long time to create changes in the earth's landscape; for example, it would take millions of years to carve river valleys of to form mountain ranges. Thus, the earth cannot be only 6,000 years old. Today, using radiometric dating, geologists have estimated the earth's age at 4.6 billion years old
Fossil Record
Fossils give us a way to trace the evolution of different lineages, perticularly by looking at the presence or absence of certain traits w/in a group. They are helpful b/c
1) they provide minimum ages for certain lineages (e.g., bats have been around for at least 50 million years, mammals for 200 million yrs, incest for 320 million yrs, vascular plant for 405 million yrs) again done by radiometric dating
2) they document extinctions in an area or of a particular group, but fossil evidence isn't perfect
Normal geological processes
volcanoe eruption, earthquakes, erosion, weathering, etc...
"is the study of the distribution of living organisms" Its goal is to describe and understand the patterns of those distributions. Biogeography gicves support to the ideas of continental drift and palte tectonics. It also has application w/in the study of evolution. In fact, it was the geographic distributions of organisms that first suggested the idea of COMMON DESCENT to Darwin.
Homologous characters
outwardly appear to have different forms or functions in different species, but internally have the same basic structure. Such traits suggest that both species inherited the trait from a common ancestor, but then, w/in each branch of the lineage, natural selection modified the structure externally to more closely suit the lifestyle of that species. Incidentally, reptile scales, bird feathers, mammalian hair, and vertebrate teeth all are made from the EPIDERMIS. Therefore, these structures are homologous!
Analogous characters
are the conceptual opposite of homologous characters. An example, is when two separate lineages have structures w/outwardly similar functions, but internally the structures have different forms. Here, the structure was not inherited from a common ancestor; rather, unrelated lineages that faced similar selective pressures from theri environments independently evolved similar structures b/c that character is suited to a particular lifestyle. Analogous characters are the result of CONVERGENT EVOLUTION. For example, both fishes and reptiles have scales covering their bodies, but they have similar functions to protect the body, the origin of the scales is different. Fish scales are made from an underlayer of skin called the DERMIS; reptile scales are made from the top layer of skin called the EPIDERMIS Both fich and reptile scales are ANALOGOUS characters that have resulted from CONVERGENT evolution.
Vestigal structures
are structures taht are present on an organism but have no apparent purpose. These structures can be explained through the theory of evolution by Natural Selction. For example, the vampire bat eats exclusively blood, but they also have molars (teeth used for grinding food). If the vampire bat evolved from an insect eating bat, it makes sense that these pointless teeth area present despite this bat's specialized diet on a liquid.
is the study of how organisms develop from a single fertilized egg into a fully developed organism ready to be born/hatched. Ex. human embryos actually have gills and a tail for a short period, while a fish embryo will retain these traits, human embryos lose them before birth. Looking at these traits and similarities provides evidence of common ancestry.
the theory of evolution be Natural Selection predicts that closely related lineages share a great deal of genetic material, and that more distantly related lineages have a greater number of differences in their DNA.
Artificial Selection
is a specific case of Natural Selection in which a trait preferred by humans becomes the preferred adaptation for that environment (a human influenced environment). In this case, humans are the agents of Natural Sel. since we decide which individuals are allowed to breed and contribute their genes to the next generation
Cambrian Explosion
refers to the geologically sudden appearance in the fossil record of animals
Radiometric Dating
is a technique used to date materials based on a knowledge of the decay rates of naturally occurring isotopes, and the current abundances.
Name 5 types of fossils that provide us info about the evolution and ecology of dinosaurs
1) eggs
2) skin
3) bones
4) feces
5) foot prints
Theory of Plate tectonics
is an idea that the continents ride on a series of rigid but highly mobile plates.
used to be Africa, South America, Antartica, Australia
a continent that used to encompass North America and Asia
Vestigal Structure
is a structure that is in a degenerate, atrophical, ar rudimentary condition or form
convergent evolution
describes the process whereby organisms not closely related independently acquire similar characteristics while evolving in separate and sometimes varying ecosystems
analogous structures
is when two different species not sharing a common ancestor but they both share common pressures from theri environment that have created similar genetic make-up, Ex. wings
Name the four condition required for evolution as a result of selection?
1) phenotypic variation among individuals w/ regards to a trait
2) This phenotypic variation must be heritable, having a genetic basis
3) Over production of offspring leads to a struggle for existence (competition for limited resources)
4) phenotypic variation results in differential survival and reproduction (this is saying that the phenotypic forms that best suit the environment that they live will be more opt to pass these traits onto their offspring, RELATIVE FITNESS
Characterize each of the following as directional, stabilizing selection: a) peppered moth; b) sickle cell-anemia c) # of eyspots on a peacocks tail; d) coat protein in TB; 5) human birth weight
a) directional
b) stabilizing
c) directional
d) directional
e) stabilizing