Lecture Exam #1 Flashcards
in 1859 when a new era of biology began, what did Charles Darwin publish?
The Origin of Species
what did the Origin of Species focus biologigts’ attention on?
the great diversity of organisms
what can evolution be defined by?
Darwin’s phrase descent with modification
what can evolution be viewed as?
a pattern and a process
who was the founder of taxonomy, the branch of biology concerned with classifying organisms?
Carolus Linnaeus
who was Darwin influenced by?
Thomas Malthus
what did Malthus note?
the potential for human population to increase faster than food supplies and other resources
who hypothesized that species evolve through use and disuse of body parts and the inheritance of acquired characteristics?
Lamarck
were Lamarck’s mechanism’s supported by evidence?
no
what helped darwin lay the groundwork for his ideas?
fossils
is the newest strata on top or bottom?
top
remains or traces of organisms from the past
fossils
where are fossils usually found?
in sedimentary rock, which appears in layers called strata
During Darwin’s travel of the Beagle what did he collect?
South American plants and animals
what was Darwin influenced by and thought the earth was more than 6,000 years old?
Lyell’s Principles of Geology
what was Darwin’s interest in geographic distribution of species kindled by?
a stop at the Galapagos Islands west of South America
what did he hypothesize about the species from South America?
that they had colonized the Galapagos and speciated on the islands
when Darwin reassessed his observations what did he precieve as to why the environment and the origin of new species are a closely related process?
adaption
what did Darwin conlude from his voyage?
that adaption must be what happened to the finches
when species become different species
speciation
Darwin’s 3 broad observations (UDM)
1) the unity of life
2) the diversity of life
3) match between organisms and their environment
the belief that Darwin had that all organisms are related through descent from an ancestor that lived in the remote past.
Descent with modification
a process that Darwin noted where humans have modified their species by selection and breeding individuals with desired traits
artificial selection
what was Darwin’s first observation?
members of a population often varied in their inherited traits
what was Darwin’s 2nd observation?
all species can produce more offspring than the environment can support, and many of these offspring fail to survive and reproduce
what was Darwin’s first inference?
individuals with traits that make them more likely to survive will tend to leave more offspring.
what was Darwin’s second inference?
this unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable traits in the population over generations
what does inference 2’s process explain?
the match between organisms and their environment
individuals with certain heritable traits survive and reproduce at a higher rate than other individuals
natural selection
what does natural selection increase the match between?
organisms and their environment over time
what is the result of natural selection if an environment changes over time?
it may result in adaption to these new conditions and may give rise to new species.
what evolves with evolution?
individuals do NOT evolve; populations evolve over time
what can natural selection do?
increase or decrease heritable traits that vary in population
what do adaptions vary with?
different environments
what are the four types of data that document the pattern of evolution?
1) direct observations
2) homology
3) the fossil record
4) biogeorgraphy
what did direct observation of evolutionary show?
evidence of natural selection
in direct observation what was natural selection in response to?
1) introduced plant species
2) the evolution of drug-resistant bacteria
when is feeding most effective?
when beak length is closely matched to seed depth within the fruit
what bacterium is commonly found in people?
Staphylococcus aureus
what one strain of a drug-resistant bacteria is a dangerous pathogen?
methicillin-resistant S. auerus (MRSA)
how does methicillin work?
by inhibiting a protein used by bacteria to produce cell walls
when are MRSA strains more likely to survive and reproduce than nonresistant S. auresus strains?
when exposed to methicillin
what are MRSA strains now resistant towards?
many antibiotics
what does natural selection create?
NOT new traits bu edits or selects for traits already present in the population.
what determines which traits will be selected for or selected in any specific population?
the current, local enviornment
similarity resulting in common ancestry
homology
anatomical resemblances that represent variations on a structural theme present in a common ancestor
homologous structures
a type of homology that reveals anatomical homologies not visible in adult organisms.
comparative embryology
what is an example of comparative embryology?
all verterbrate embryos have a post-anal tail and pharyngeal arches
remnants of features that served important functions in the organism’s ancestors
vestigial structures
what are examples of homologies at the molecular level?
genes shared among organisms inherited from a common ancestor
hypotheses about the relationship among different groups.
evolutionary trees
what do homologies form in evolutionary trees?
nested patterns
how can evolutionary trees be made?
using different types of data
what is an example of the different types of data made by evolutionary trees?
anatomical and DNA sequence data
the evolution of similar or analogous features in distantly related groups
convergent evolution
what does convergent evolution not provide information about?
ancestry
provides evidence of the extinction of species, the origin of new groups and changes within groups over time
fossil record
what do fossil records prove?
similarities to present day organisms
what can fossils document?
important transistions
what is an example of an important transition that fossils documented?
the transition from land to sea in the ancestors of cetaceans
the scientific study of geographic distribution of species, provides evidence of evolution
biogeography
what was Earth’s single large continent called?
Pangaea
what caused Pangaea to separate?
continental drift (earthquakes, natural events)
what does an understanding of continent movement and modern distrubution of species allow us to predict?
when and where different groups evolved
types of species that are not found anywhere in the world
Endemic species
how did Darwin explain endemic species?
he said that species from the mainland colonized islands and gave rise to new species as they adapted to new environments.
in science, what does a theory account for?
many observations and data and attempts to explain and intergrate a great variety of phenomena
what does Darwin theory of evolution by natural selection integrate?
diverse areas of biological study
what did the diverse areas of biological study from Darwin’s theory of evolution by natural selection stimulate?
many new research questions
what adds to our understanding of evolution?
ongoing research
the study of heredity, the process in which a parent passes certain genes onto their children
genetics
what are some specific traits that a parent may pass to their child through genetics? (3) (PNG)
1) physical characteristics
2) natural talents
3) genetic disorders
describes how some traits are passed from parents to their children
heredity
small sections of DNA that are coded for specific traits
genes
where are genes found?
on chromosomes
how many sets of chromosomes do humans have?
23, one set from each parent
any of the alternative versions of a gene that may produce distinguishable phenotype effects
allele
fully expressed in phenotype of a heterozygote
dominant
phenotype effect is not observed in a heterozygote
recessive
having two identical alleles for a given gene
homozygous
having two different alleles for a given gene
heterozygous
the genetic makeup, or set of alleles of an organism
genotype
the observable physical and physiological traits of an organism, which are determined by its genetic makeup
phenotype
the inherited traits are determined by genes that are passed from parents to children
mendelian inheritance
according to mendelian inheritance what is true of a trait and gene?
a trait may not be observable, but its gene can be passed to the next generation
according to Mendel if mom has freckles (F) and dad doesn’t (f) what is true of the child?
it has inherited the gene pair of alleles (Ff)
the idea that genetic material from two parents blends together (blue and yellow paint make green)
“blending” hypothesis
the idea that parents pass on discrete heritable units (genes)
“particulate” hypothesis
how did Mendel document a particulate mechanism?
through his experiments with garden peas
what did Mendel discover through his experiments with breeding garden peas in carefully planned experiments?
the basic principle of heredity
advantages of pea plants for genetic study (4) (MMEC)
1) many varieties with heritable features, or characters (color)
2) mating of plants can be controlled
3) each pea plant has sperm-producuing organs (stamens) and egg-producing organs (carpels)
4) cross-pollination
what are character varients called such as purple or white flowers?
traits
fertilization between different plants and can be achieved by dusting one plants with pollen from another
cross-pollination
mating two contrasting, true-breeding varieties
hybridization
in a typical experiment, what did Mendel do?
hybridization
what are true-breeding parents called?
the P (parental) generation
what is the hybrid offspring of the P generation called?
the F1 generation
when F1 individuals self-pollinate what is produced?
the F2 generation
when Mendel crossed contrasting, true-breeding white and purple flowered pea plants what happened?
all of the F1 hybrids were purple
when Mendel crossed the F1 hybrids, what was the result?
many of the F2 plants had purple flowers, but some had white
what did Mendel discover from crossing the purple and white flowers?
the three to one ratio, purple to white flowers in the F2 generation
what did Mendel always begin his experiments with?
true breeding parents
those when self-pollinated, all offspring are the same variety
true breeding parents
during hybridization does blending occur?
no
with hybridization was the white flower trait lost?
no, it either, wasn’t diluted. it showed up in the second generation
what did Mendel reason about the color of the flowers?
that only the purple flower factor was affecting flower color in the F1 hybrids
what did Mendel call the purple and white flower color?
the purple color a dominant trait and the white a recessive
what else did Mendel observe to prove his point?
the same pattern of inheritence of 6 other pea plants characters, each represented by 2 traits
what did Mendel call what we now call a gene?
a “heritable factor”
what did Mendel develop a hyptothesis to explain?
the 3:1 inheritence pattern he observed in F2 offspring
how many related concepts make up Mendel’s model?
4
what are the four concepts of Mendels model related to?
what we now know about genes and chromosomes
what is the 1st concept of Mendel’s model?
that alternative versions of genes account for variations in inherited characters
what is an example of the 1st concept of Mendel’s model?
the gene for flower color in pea plants exist in 2 versions, one for purple flower and the other for white
what are the alernative versions of genes now called?
alleles
where does each gene reside at?
a specific locus on a specific chromosome
what is the 2nd concept of mendel’s model?
for each character an organism inherits two alleles, one from each parent
what did Mendel make his deduction without knowing about the character inheriting 2 alleles?
the role of chromosomes
According to Mendel’s 2nd concept, what may be true of the two alleles at a locus on a chromosome?
they may be identical, as in the true-breeding plants of Mendel’s P generation or they may differ as in the F1 hybrids
what is the 3rd concept of Mendel’s model?
if two alleles at a locus differ, then one (the dominant allele) determines the organism’s appearance and the other (recessive) has no noticeable effect on appearance
what is an example of the 3rd concept of Mendel’s model?
the flower-color, the F1 plants had purple flowers because the allele for that trait is dominant
what is the fourth concept of Mendel’s model
now known as the law of segregation
states that two alleles for a heritable character separate during gamete formation and end up in different gametes
law of segregation
how can the possible combination of sperm and egg be shown?
in a punnett square
a diagram for predicting the results of a genetic cross between individuals of known genetic makeup
punnett square
what represents a dominant and recessive allelle?
a capital letter for dominant and lower-case for recessive
are homozygotes true-breeding?
yes
are heterozygotes true-breeding?
no
because of the different effects of dominant and recessive alleles what do an organisms traits no always reveal?
its genetic composition
if the offspring display the recessive phenotype what must the mystery parents be?
heterozygous
an observable heritable feature that may vary among individuals
population
one or two or more detectable variants in a genetic character
trait
referring to organisms that produce offspring of the same variety over many generations of self-pollination
true breeding
a cross between two oraganisms that are heterozygous for the character being followed (or the self-pollination of a heterozygous plant)
monohybrid cross
the first filial, hybrid (heterozygous) offspring arising from a parental (p generation) cross
F1 generation
the offspring resuling from interbreeding (or self-pollination) of the hybrid F1 generation
F2 generation
how does sexual recombination generate genetic variability?
by recombining existing alleles
a localized group of individuals capable of interbreeding and producing fertile offspring
population
a population or group of populations whose members have he potential to interbreed in nature and produce viable, fertile offspring but do not produce viable, fertile offspring with members of other such groups
species
consists of all the alleles for all loci in a population
gene pool
the contribution of an individual makes to the gene pool of the next generation, relative to the contributions of other individuals in the population
relative fitness
genetic variation that does not provide selective advantage or disadvantage
neutral variation
5 conditions of the Hardy-Weinberg equilibrium (5) (NRNEN)
1) no mutations
2) random mating
3) no natural selection
4) extremely large population
5) no gene flow
the evolution of similar or analogous features in distantly related groups
convergent evolution
when does analagous traits arise?
when groups independently adapt to similar environments in similar ways
what does convergent evolution not provide?
information about ancestry
