Exam 1 Flashcards
before 1960s, all life was in one of two kingdoms
plants and animals
field of view
-amount of slide visible at one time decreases as magnification increases
depth of field
-thickness of slide in focus at one time decreases as magnification increases
light intensity
-amount of light passing through to your eye
-decreases as magnification increases
-controlled by :
-rheostat (adjusts intensity)
-iris diaphragm (adjusts contrast)
drawing for biology
-art and science coexist
-much of science began with artists observing natural organisms and phenomenon
-careful observation is a fundamental skill as a biologist
-scientific drawings help to keep a record of oberservatins of your specimens
Blind contour drawing
an exercise where you draw the outline of a subject without looking at the paper
contour drawing
-about depiciting the object only with lines, and not shading
-a contour refers to the outside line of a form. it establishes the layout, size, and emphasis
scientific drawings
-must be in pencil
-draw more than one cell for tissues
-dont use shading
-labels to right when few
-draw only what is actually visable
-include detailed figure caption
taxonomy
-based on evolutinoary relationships
-three parts
1: classification
2: nomenclature
3: identification
-three domain system
-archaea, bacteria, eukarya
classification: hierarchy
Domain = eukarya
kingdom = animalia
phylum =chordata
class = mammalia
order = primates
family= hominidae
genus = homo
species = sapiens
domain is most inclusive, species is least inclusive
nomenclature
-names of taxa at various levels of hierachy come from latin and greek roots
-binomial names
-exclusive 2-part name for each organism
-genus + specific epithet = species
-often descriptive for certain traits of the organism
example: canis familiaris
canis from latin for dog, familiaris from latin for family
phylogeny
-evolutionary history of group of related organisms
-represented as “tree”
-branching reflects evolutionary relationships (lineages)
node
-point of change of a trait from one state to another (derived)
-defines a lineage
-represent the common ancestor of lineages after branch point
-taxa that are more related share a more recent common ancestor
identification: Dichotomous keys
-used to identify unknown specimens
-provide a series of couplets that lead to an identification (1a, 1b)
-each part of a couplet is mutually exclusive of the other
-focus on characters unique to given group of organisms
-good keys will use 2-3 characters at each step
there are three broad groups that organisms fall
Domain Bacteria, Domain Archaea, and Domain Eukarya (Eukaryotes)
organisms previously classed as kingdom monera (prokaryotes) are now
split into 2 domains- bacteria and archaea
Domain Eukarya organisms are further classified into informally groups called-
supergroups
phylogeny definition
history of evolution of a species or group, especially in reference to lines of decent and relationships among broad groups of organisms
taxonomy definition
a system of classification
taxonomy is the-
branch of biology that deals with all aspects of classifying the diverse forms of life
what are the three facets to taxonomy:
1: arrangement of organisms into groups based on shared similar characters (classification)
2) assignment of names to taxa or groups (nonmenclature)
3) arrangement of the classification into a form that can be used to identify specimens, such as a dichotomous key ( identification)
1) classification
descriptions based on quantitative or qualitative traits
based on obersevations of traits and the development of detailed descriptions to differentiate a group of species from all other species
once it is described it is grouped with others like it and ranked in a hierarchical manner called classification
qualitative
why, how, what behind behaviours
quantitative
how many or measurable data
2) Nomenclature
Whats in the name?
a system for scientific naming of organisms within an internationally accepted set of rules
once species have been determined to be a novel and the relationship to other related species determined, the taxonomist can choose a name
new name can relate to some characteristic of the new organism such as shape, colour, size, geographic location, or may be named in honour of somone
genus is always-
capitalized while the specific epithet remians in lower case
always italic or underlined
Helianthus annuus
when refereing to more than one genus, it is written as Helianthus spp.
if the species name in unknown you can use Helianthus sp. (sp is regular font)
binomial
a two-part latin name
always written out in full the first time, then the genus can be abbreviated
H. annuus
Hierarchy
a wolf is first recognized as Eukarya (Domain), then as an animal (Kingdom), then Chordata (Phylum), mammmalia (class), Carnivora (order), canidae (family)
what is the entire hierarchy from most to least inclusive?
Domain, Kingdom, Phylum, Class, Order, Family, Genus, species
(DOGS KICK PEOPLE CUZ OLDER FEMALES GOT SPICEY)
how do trees work
-the names along the top of the figure are the taxa (taxon)
-the line connecting each taxon is a branch and the point where two or more branches connect is called the node
-the node represents the common ancestor of the taxa at the end of the connecting branches.
we can trace related taxa back to a common ancestor from which the inherited specific traits
identification
dichotomous keys are useful and are the fastest and most reliable method
keys are contructed in a series of paired, mutually exclusive statements (couplets) that divide a set of objects into smaller groups in a series of steps
at each step you will choose between two statements, then either determine or move to another couplet
another word for dichtomous key
taxonomic
rules to dichotomous keys
-each step requires a couplet with mutually exclusive characteristics
-couplets are designated by numbers and statements within the couplet by lower case letters 1a and 1b
-each step in a group distinguishes the organisms into two smaller units where each unit either identifies and names an object or gives directions as to where to go next in the key
-the beginning couplets tend to focus on more general characteristics while later couplets refer to increasingly specific traits
-couplets should not be based on statements of relative size, subtle differences in colour, general shape, etc. as these characteristics can be ambiguous, can change in preserved specimens, and often are only distinguishable if all aspects can be compared in the specimens
-each couplet should contain more than one characteristic in case some features are not distungishable on the specimen. it is not good form to use the statement “not above characters”
2 scales of evolution
microevoluton
macroevolution
evolution occurs through
natural selection
gene flow
genetic drift
mutations and adaptations
-random changes in DNA
-Favourbale changes are preserved
allele
an alternative version of a specific gene
genotype
genetic composion of an organism
phenotype
expression of measurable triats based on genotype
population
a group of individuals sharing the same space and time
gene pool
the total number and kind of alleles in genes of interest in a population
natural selection
-observations
-variation among individual inherited traits
-not all offsrping survive to reproduce due to competition for limited resources
-inferences
-best adapted individuals leave more offspring
-most favorable traits passed on
evolution via natural selection
-heritability
-veriabliity
-reproductive advantage
evidence for adaptive evolution sea urchin
-they belong to phylum echinodermata
-dwell on ocean floor and tidal zones
-bilateral larvae
-secondary radial symmetry as adults
-spiny calcareous endoskeleton
-well developed body cavity
-unique locomotion, feeding and gas exchange (water vascular system)
-complete digestive tract
the theory of evolution is-
our understanding of the biological diversity
descent with modification
links all organisms back to a common ancestor
the main idea of natural selection and adaptive evolution
a population of organisms will change over time in peeps with certain heritable traits have better reproductive success than other peeps
populations contain-
a pool of alleles that have arisen through random mutations and recombination
microevolution
small-scale evolutionary changes in allele frequencies within a population
changes are observed over a short time and can be reversible
peeps in these pops are still able to mate and produce viable offspring
macroevolution
a process where evolutionary events result in the creation of a new species or taxonomic group, diffrent from parent
at some point peeps in the pop accumulate so many heritable mutations that they are no longer capable of reproducing with their ancestral organisms and a new species is formed
natural selection is a-
non-random process that favours adaptive traits
if these adaptive traits have a genetic basis (heritable), natural selection can result in evolution- a change in frequency of a heritable trait as it passes from one gen to the next
the trait under consideration must have:
heritablity
variability
reproductive advantage
what are two random processes
the bottleneck and the founder effect which cause genetic drift or random changes in the genetic status of a pop
bottle neck effect
a reduction in the size of a pop as a result of mortality that is not due to the quality of a person traits but is simply a result of ‘bad luck’
(natural disasters)
-after disaster- changes allele freqencies resulting in evolution
the founder effect
the seperation of a few peeps into a new pop by a random process that is also not due to the quality of their traits
the genetic makeup of the ‘new’ pop likely differs from that of the founding pop
genetic drift is much-
stronger in small pop then large ones
adaptations
characteristics that are favoured by natural selection lead to adaptations, which increase the fitness and functioning of the peeps in relation to its environment
allow organisms to deal with selection pressures in their habitat and lifestyle
-they can be structural, behavioural, or physiological
structural adaptations
traits such as body shape, type of appendages or fur colour
behavoural adaptations
changes in the way an organism behaves to deal with environmental pressures, such as making food caches, sleeping underground
physiological adaptations
traits are also part of an organisms phenotype because they represent the biological function of some anatomical feature
-large ears on a rabbit help it hear, but also function for heat dispersal from the central core of the body to the environment during hot weather
adaptive evolution
pops naturally exhibit genotypic and phenotipic variation and peeps with traits that are better suited in a given havitat will compete better and leave more offspring
many adaptations taken together can help us infer how adaptive evolution plays an important role in the evolutionary history of a species
how might radial symmetry be an advantage for sea urchins?
it could sense a threat or food from all sides of it
what is the function of pedicellariae?
pincers that help move and grab food, as well as remove unwanted things
what is a coelom
the fluid- or air-filled body cavity that separates the digestive tract from the endoskeleton body covering
why is the water vascular system important for the sea urchin?
to feed and get rid of waste, respiration, and so that it can move
phylogeny
-hypothesis of the evolutionary relationships between organisms of interest
-shown as “tree”
-branching of different organisms indicates evoutionary relationships between linegaes
node
-point of chnage of a trait from one state to another
-defines lineage
-based on shared derived characteristics
plesiomorphic
plesio = ancestral condition
sym-pleisiomorphy = shared ancestral trait
apomorphic
apo= derived condition
syn- apomorphy = shared derived trait
-traits that define specific groups or clades
aut- apomorphy = derived trait that is not shared
polarizing characters
-determining which character states are plesiomorphic and which are apomorphic
-(0) - if the ingroup taxon has the same character state as the outgroup (has ancestral/plesiomorphic condition
-(1)- ingroup taxon has a different state for a given character relative to outgroup (has the apomorphic condition for that state)
parismony
-principle used to decide between several hypotheses; simplest interpretation of data = likely correct explanation
measuring parsimony
tree length
- measure of number of changes in character states (sum of characters mapped)
-shortest TL = most parsimonious tree (least steps)
consistency index
-measure of how many times a specific trait changes state
-calculated by number of characters/ TL
monophyletic
contains most recent common ancestor of all group members and all of its decendants
-also called a clade
types of lineages
monophyletic
paraphyletic
polyphyletic
paraphyletic
-contains most recent common ancestor of all group members and some of its descendants
polyphyletic
-does not include most recent common ancestor of all group members
-members derived from 2 or more ancestral forms
vertebrae
during the cambrian period, a lineage of chordates gave rise to vertebrates
a skeletal system and more complex nervous system fostered more complex behavours
jaws
hagfish and lampreys dont have jaws
jawed vertebrates include sharks and their relatives, rey-finned fishes, lobefinned fishes, amphibans, reptiles, and mammals
skeleton
-the cartilaginous skeletons of the chondrichthyans can be mineralized with calcium for added support
eggs
amniotic egg is an egg that contains additional membranes designed to protect the growing embryo
-it may or may not have an external shell
thermoregulation
-poililothermy is found in organisms that do not have an internal mechanism for maintaining a constant body temp
-homeothermy is found in organisms that have an internal mechanism to maintain a very stable and constant body temp
mammary glands
-mammary glands produce milk for the vertebrate young
-this characters is associated with the presence of ‘hair’
myxini
hagfish
petromyzontida
lampreys
chondrichthyes
sharks, skates, rays
amphibia
frogs, toads, salamanders
reptilia
turtles, birds, snakes, lizards
mammalia
rodents, carnivored, primates, ungulates, etc
the greater the resemblance between two species-
the more recently they diverged from a common ancestor
phylogeny
a hypothesis of evolutionary relationships among a set of organisms
ancestral and derived
the time of the apperance certain traits in evolutionary history
ancestral
-plesiomorphic
-found in the earliest member of the lineage
derived
-apomorphic
-found in later members of the lineage
-a derived trait is changed from the ancestral form
derived characters
-synapomorphies
-traits that are shared by two or more groups of taxa, and that originated in their common ancestor
shared, ancestral characters states are called
symplesiomorphies
a character that is exhibied by a single taxon only is called-
an autapomorphy
these characters are not shared and are therefore not useful in generating evolutionary trees
homologous structures
structures that are similar in different organisms because of a shared ancestry
result from divergent evolution
homologous = descended from the same primitive structure
(forarms from humans, bats, and birds are homologous cuz they are derived from an ancestor that had the basic forelimb plan)
anologous
structures that performm the same function without being present in a common ancestor
(body shape of a shark and dolphin)
how do organisms come to resemble one another if they were not derived from a common ancestral character?
convergent evolution
-species from different evolutionary lineages may have similar ecological roles, and antural selection then drives analogous adaptations
sister taxa
-groups that share a common ancestor and are more related to each other than to other groups
parsimony
the principle we use to decide between several hypotheses
cladistics
a method of determining evolutionary relationships by analyzing the features they share
-differences between lineages start to accumulate once lineages have separated. then many shared, homologous features should indicate a recent common ancestor and a high degree of relatedness
a phylogenetic tree obtained via cladistics is termed a-
cladogram
homoplasy
a collective name for a series of conditions that violate the assumptions of cladistic analyses
cladistics makes the assumption that species share derived characters because they share a common ancestor that had those specific derived characters, however, sometimes convergences occur and there are independent orgins of a feature in unrelated lineages
cladistic analysis assumes that if a species does not have a derived character, it is cuz its most recent ancestor diverged before that derived character originated
sometimes lineages have reversals
reversals arise when-
a lineage has exhibited a derived character at some point in its evolutionary history, but that charcter reverts to an ancestral state
polarizing characters
the process of determining which character states are plesiomorphic and which are apomorphic
-if an ingroup taxon possesses the same charcter state as the outgroup has the ancestral/ plesiomorphic condition for that character state and it is assigned a zero
if it instead has a different state for a given character relative to the outgroup, it has the apomorphic (derived) conditin for that state and it is assigned a one
tree length (TL)
thecriterion used by the maximum parsiomony method to search for the best tree
defined as the sum of the minimum numbers of substitutions over all sites for the given topology
a sum of the number of times each character is mapped onto a tree
consistency index (CI)
a tree statistic that measures the number of times a single character changes
CI = total number of characters used in the data set/ TL
ideally, we are looking for a tree with character changes appearing only once
A CI lower than one indicates that homoplasy exists somewhere in the tree
character mapping
occurs when a character state change is mapped between the ancestor (node) that has one state, and the descendent that has another state
usually a mark
monophyletic groups or clades
-groups that contain the most recent ancestor and all of the descendants
