Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

102 Cards in this Set

  • Front
  • Back
a group of the same kind of organisms in some specified area
includes all populations of all species in some specified area
a community interacting with its environment
encompasses all regions of Earth's crust, waters, and atmosphere in which organisms live
different kinds of organisms
one or more species grouped on the basis of a number of unique shared traits
single cells that are prokaryotic (no nucleus)
archea and bacteria
multicelled, photosynthetic producers
multicelled comsumers that secrete enzymes that digest food outside the body, and then their individual cells absorb the digested nutrients
multicelled consumers that ingest the tissues of other organisms
changes in DNA that lead to new traits
heritable change in a line of descent
a proposal that explains the cause of something that is observable
a statement of what you should find in the natural world if you were to go out looking for it
making observations, conducting an experiment, or formulating a model
theoretical, detailed descriptions of partially-understood processes
the hypothesis is consistent with all of the data that has been collected and it is now used to make different predictions
scientific theory
a feature of an object or event that may differ over time or among the representatives of that object or object
a standard for comparison with one or more experimental groups. There are 2 kinds.
control group
a case of looking like something else and confusing predators or prey
data taken from a sample might differ from data taken from the whole. This difference is called...
sampling error
organized systems of retrieving info about how species fit in the big picture of living things
classification systems
family, order, phylum, and kingdom
higher taxa
all prokaryotes are assigned to the kingdoms Bacteria and Archea, and all single-celled eukaryotes to kingdom Protista. Animals, plants, and fungi are separate kingdoms
six-kingdom classification system
the three highest taxa are Bacteria, Archea, and Eukarya
three-domain system
each set of species descended from just one ancestral species
monophyletic group or clade
a novel feature that evolved only in one species and is present only in its descendants
derived trait
RNA is a template for protein synthesis
RNA world
simple membrane sacs that could surround and protect info-storing templates and metabolic events
lasted from 3.8 billion to 2.5 billion years ago
Archean eon
have no nucleus
prokaryotic cells
some populations diverged in 2 major directions
Bacteria and the shared ancestor of Archea and Eukaryotic cells
bacteria that formed flattened mats through photosynthesis. These mats are called...
a donor cell's sex pilus latches onto a recipient cell and then retracts, pulling it close
prokaryotic conjugation
a small, self-replicating circle of DNA with just a few genes
infectious, disease-causing agents invade target species and multiply in or on them
the transfer of genetic info between cells (often of different species) by conjugation or some other process
lateral gene transfer
archea that are salt lovers. Most are aerobic
archea that live in oxygen-free habitats (wetland mud, gut of mammals, and hydrothermal vents). All are anaerobic
archea that thrive in temperatures above 80 degrees censius. All are anaerobic
stone-hard evidence of earlier forms of life
a single time of creation that populated the entire world. Major catastrophes killed species but the survivors repopulated the world
gradual, uniformly repetitive change in the landscape of the world
an individual's success in a given environment, as measured by its relative contribution to future generations
a random change in allele frequencies over time, brought about by chance alone
genetic drift
when all of the individuals of a population have become homozygous for one allele only at a locus
a drastic reduction in population size brought about by selection pressure or a calamity
a few individuals leave a population and establish a new colony elsewhere
founder effect
mating between close relatives, which share many identical alleles
a physical flow of alleles between populations
gene flow
units of DNA info about traits, transmitted from parents to offspring
different molecular forms of the same gene
offspring of a cross between 2 individuals that breed true for different forms of a trait
a pair of dominant alleles (AA)
homozygous dominant
a pair or recessive alleles (aa)
homozygous recessive
a pair of nonidentical alleles (Aa)
the range of small differences in many traits in a population
continuous variation
this curve is typical of any trait that shows continuous variation
substance that is large and acidic and contains nitrogen and phosphorus
viruses that infect bacteria
atoms in the molecules scatter the x-rays in a pattern that can be captured on film
x-ray diffraction image
an organism into which DNA from another species has been inserted
transferring an organ from one species to another
some heritable aspect of form, function, behavior, or development that improves the odds for surviving and reproducing in a given environment
The first step of protein synthesis - when a gene serves as a template for making RNA (can make mRNA, rRNA, or tRNA)
The second step of protein synthesis - the genetic info carried by a strand of RNA is decoded into a sequence of amino acids that is assembled into a new polypeptide chain
the only class of RNA that carries protein building instructions
messenger RNA (mRNA)
RNA that is a component of ribosomes (a large molecular structure upon which polypeptide chains are builtI
ribosomal RNA (rRNA)
RNA that delivers amino acids one at a time to a ribosome
transfer RNA (tRNA)
toxins that some microorganisms in soil release to kill bacterial competitors for nutrients
natural antibiotics
the formation of sedimentary rock layers
one line of descent
used to calculate a sample's age
radiometric dating
the time it takes for half of a radioisotope's (an atom of an element with an unstable nuclues) atoms to decay
a chronology of Earth's history
geologic time scale
major patterns, trends, and rates of change among lineages
a supercontinent that comprised most of the land on earth 420 million years ago
260 million years ago, Gondwana had joined with all other major land masses to become this supercontinent
model used to estimate relative times of divergences by comparing the number of neutral mutations in the DNA of different species
molecular clock
the study of body forms and structures of major groups of organisms
comparative morpology
similarities in one or more body parts, which hint at inheritence from a shared ancestor
homologous structures
change from the body form of a common ancestor
morphological divergence
when dissimilar body parts evolved in similar ways in evolutionary distant lineages (ex: birds, bats, and insects all have wings but they are not related species)
morphological convergence
structural adaptations that are the result of similar challenges in the environment, but they are derived from dissimilar body parts of distantly-related lineages (bird, bat, and insect wing)
analogous structures
a concept that says that populations belong to the same species as long as their members share traits that allow them to interbreed and produce fertile offspring
biological species concept
After gene flow has stopped entirely, mutation, natural selection, and genetic drift begin to operate independently in each isolated population until their gene pools change. Can lead to new species
genetic divergence
the process by which a new species arises
after gene flow has ended, these heritable aspects of body form, function, or behavior prevent interbreeding between divergent populations
reproductive isolating mechanisms
genetic changes that lead to a new species often arise after a physical separation occurs between populations
allopatric speciation
a species may form within the home range of an existing species, in the absense of a physical barrier
sympatric speciation
when individuals inherit 3 or more sets of chromosomes characteristic of their species
when populations that are maintaining contact along a common border become distinct species
parapatric speciation
when a lineage splits, the population become genetically isolated and they diverge
one species can evolve into another species without branching through mutations and changes in allele frequencies
a drawing that summarizes info about the continuity of relationships among groups
evolutionary trees
model that says that species originate by small changes over long time spans
gradual model of speciation
model that explains for different patterns (rapid then gradual) of speciation
punctuation model of speciation
a burst of divergences from a single lineage. It gives rise to many new species
adaptive radiation
A set of different niches that become filled typically with by a related group of species. Adaptive radiation requires these
adaptive zones
A way for a species to enter an adaptive zone: a chance modification in some body structure or function gives it the opportunity to exploit the new environment more efficiently
key innovation
an irrevable loss of a species
catastrophic losses of entire families or other groups
mass extinction