Biology Flashcards
1
Q
6 kingdoms
A
Bacteria, archaea, Protista, fungi, plantae, and animalia
2
Q
What are the 2 major cell types
A
Prokaryotic & Eukaryotic
3
Q
More complex than prokaryotes
A
Eukaryotes
4
Q
Cell membrane
A
Aka plasma membrane
Regulates passage of materials into and out of the cell
Consists of phospholipid bilayer w/ proteins embedded throughout the
5
Q
Nucleus
A
Contains dna wound structural proteins called histones
6
Q
Ribosome
A
Facilitate protein production
7
Q
Endoplasmic reticulum
A
Network of membrane enclosed spaces involved in the transport of materials throughout the cell, particularly those materials destined to secreted by the cell
8
Q
Golgi apparatus
A
Primary for cellular trafficking
9
Q
Mitochondria
A
Sites of aerobic respiration
Conversion of sugars, fats, and other sources of fuel into usable energy (ATP)
10
Q
Cytoplasm
A
Where most of the cell’s metabolic activity occurs
Includes cytosine and all organelles of the cell
11
Q
Cytosol
A
Cellular fluid contained within cell membrane
12
Q
Cyclists
A
How transport w/in cytoplasm occurs
Streaming movement w/in the cell
13
Q
Animal cell vacuole
A
Smaller than plant ones
Transport vesicle for exocytosis & endocytosis
Storage of water & minerals
14
Q
Centrioles
A
Composed of microtubules
Involved in spindle organization during cell division
15
Q
Lysosomes
A
Contain hydrolytic enzymes involved in intracellular digestion
Break down materials ingested by the cell
16
Q
Cytoskeleton
A
Supports the cell, maintains its shape, and aids in cell motility
17
Q
Components of cytoskeleton
A
Microtubules
Microfilaments
Intermediate filaments
18
Q
Microtubules
A
Hollow rods of polymerized tubulin
Provide framework for organelle movement
19
Q
Cilia and flagella
A
Specialized arrangements of microtubules
Involved in cell motility & cytoplasmic movement
20
Q
Microfilaments
A
Solid rods of actin
Cell movement and support
Move materials across the plasma membrane
21
Q
Intermediate filaments
A
Like keratin
Serve as structural backbone of the cell
Can withstand a lot of tension
Help anchor organelles
22
Q
Simple diffusion
A
Net movement of dissolved particles down their concentration gradient
23
Q
Osmosis
A
Simple diffusion of water from region of lower solute concentration to a region of higher solute concentration
24
Q
Hypertonic cell
A
Water will flow out of the cell into the surrounding medium
25
Plasmolysis
Will cause cell to shrivel
26
Hypotonic
Water will flow into the cell causing it to swell and lyse
27
Lyse
Burst
28
Isotonic
Having the same concentration inside and outside the cell
29
Facilitated diffusion
Net movement of dissolved particles down their concentration gradient thru special channels or carrier proteins in the cell membranes
30
Active transport
Net movement of dissolved particles against their concentration gradients
Requires energy
31
Symporters
Move 2+ ions or molecules in the same direction across the membrane
32
Antiporters
Exchange 1+ ions or molecules for another ion or molecule across the membrane
33
Active transport pumps
Energy dependent carriers; require ATP
34
Endocytosis
Cell invaginates, forming vesicle that contains extracellular medium
Bring large volumes of extracellular material inside the cell
35
Pinocytosis
Ingestion of fluids or small particles
36
Phagocytosis
Engulfing of large particles
37
Exocytosis
Release a large volume of contents to the outside
38
Unicellular organism cell division
Means of reproduction
39
Multicellular organism cell division
Method of growth, development, and replacement of worn out cells
40
2 courses of cell division
Mitosis and meiosis
41
Interphase
Period of growth and chromosome replication
Cell spends 90% of life here
42
G1 interphase
Initiates interphase
Active growth phase
Varies in length
Cell increases in size and synthesizes protein
Length of this phase determines length of entire cell cycle
43
s interphase
Period of dna synthesis
44
G2 interphase
Cell prepares to divide
Grows and synthesizes protein
45
M phase
When mitosis or meiosis occurs
46
Mitosis
2 daughter cells
Takes place in somatic cells
Nuclear division followed by cellular division
4 phases: prophase, metaphase, anaphase, and telophase
47
basic unit of DNA
nucleotide
48
nucleotide composition
deoxyribose (a sugar) bonded to a nitrogenous base
49
2 types of nitrogenous bases
purines and pyrimidines
50
purines in DNA
include adenine (A) and guanine (G)
51
pyrimidines in DNA
include cytosine (C) and thymine (T)
52
RNA exclusive nitrogenous base
uracil (U) instead of thymine (T)
53
larger in structure due to possessing a 2 ring nitrogenous base
purines compared to pyrmidines
54
purines pair with pyrimidines in what pattern
T forms 2 hydrogen bonds w/ A, and G forms 3 hydrogen bonds w/ C
55
arrangement of DNA
double stranded, antiparallel arrangement
Discovered by Watson & Crick
56
DNA helicase
breaks hydrogen bonds b/w nitrogenous bases from each strand
57
replication fork
the opening in the DNA molecule created by DNA helicase
58
topoisomerase
removes torsional strain by cutting, twisting, and then rejoining the strands of DNA
59
replication bubble
each single strand can as a template for complementary base pairing.
allows for synthesis of 2 new daughter strands
60
semiconservative replication
each new daughter helix contains an intact strand from the parent helix and a newly synthesized strand
61
DNA polymerase
reads the parent DNA strand & creates a complementary, antiparallel daughter strand.
always reads the parent strand in the 3'-->5' direction which creates the daughter strand in the 5'--> 3' direction.
can only add nucleotides to the 3' ends
62
lagging strand of DNA
has its 3' end facing away from replication fork.
synthesis and movement of replication fork are in opposite directions.
63
leading strand of DNA
has its 3' end facing toward the replication fork.
continually synthesized.
64
okazaki fragments
short fragments of synthesized DNA
65
DNA ligase
joins together DNA fragments
66
gene
unit of DNA that encodes a specific RNA molecule thru the process of transcription and thru translation, that gene can be expressed as a protein
67
transcription
process in which genetic info is passed from DNA to RNA
68
template strand
complementary to the transcription of RNA in the 5'-->3' direction
69
coding strand of DNA
identical to mRNA strand
70
translation
process in which genetic info is passed from mRNA to protein
71
ribonucleic acid (RNA)
a polynucleotide that is structurally similar to DNA but the exceptions of
- sugar constituent is ribose
- uracil in place of thymine
- most RNA is single stranded
72
where is RNA found in the cell
nucleus and cytoplasm
73
3 major types of RNA
mRNA, tRNA, and rRNA
74
messenger RNA
- carries the complement of DNA sequence
- transports info from the nucleus to the ribosomes for protein synthesis
- made from ribonucleotides complementary to the template strand of DNA
75
transfer RNA
- found in cytoplasm
- assists in translation of mRNA's nucleotide code into sequence of amino acids
76
anticodon
- 3 nucleotide sequence
- complementary to 1 of the mRNA codons
77
charged tRNA
when a tRNA is complexed w/ the appropriate amino acid
78
approx. 40 known types of tRNA
at least one type for each amino acid
79
ribosomal RNA
- synthesized in the nucleolus of eukaryotes and in the cytoplasm of prokaryotes
- integral part of ribosomal machinery during protein assembly
- most abundant RNA in the cell
80
TATA box
approx 30 bp upstream
sequence of TATAAT
81
Pribnow box
approx 10 bp upstream
sequence of TTGACA
82
introns
extra sequences & are subsequently spliced out by the spliceosome
"INtrons stay IN the nucleus"
83
exons
nucleotides necessary to make the proteins & are kept during the post-transcriptional processing
"EXons will EXit the nucleus as part of the mRNA"
84
codons
the 3 nucleotide sequences on the mRNA that correspond to a specific amino acid.
there are 64 possible codons.
all codons are written in the 5'-->3' direction
85
stop codons
instruct the ribosome to the stop translation
- UAA (U Are Annoying)
- UGA (U Go Away)
- UAG (U Are Gone)
86
translation
process thru which mRNA codons are translated into a sequence of amino acids.
occurs in cytoplasm & involves ribosomes, amino acids, enzymes & other proteins
87
4 stages of translation
initiation, elongation, translocation, & termination
88
initiation stage of translation
when the ribosomal subunit binds to the mRNA near its 5' end
89
elongation stage of translation
3 step cycle repeated for each amino acid.
ribosome moves in the 5' to 3' direction along the mRNA
90
3 important binding sites of the ribosome
A-site: holds the incoming aminoacyl-tRNA complex
P-site: holds the tRNA that carries the growing polypeptide chain, and where initiation complex formed
E-site: where the now uncharged tRNA briefly pauses before it is expelled from the ribosome, to be recharged
91
peptide bond
formed when polypeptide is passed from the tRNA in the p-site to the tRNA in the a-site
92
translocation stage of translation
ribosome advances 3 nucleotides along the mRNA in the 5' to 3' direction
93
termination stage of translation
triggered once a stop codon is encountered
94
order of sites in the ribosome during translation
APE
A-site to P-site to E-site
95
post-translational modifications
polypeptide chain undergoes modifications to become fully functional.
can include cleavage or addition
96
cleavage
certain amino acids sequences are removed from the chain
97
addition
biomolecules are added to the peptide
98
common addition processes
phosphorylation, carboxylation, glycosylation, prenylation
99
phosphorylation
addition of phosphate group
100
carboxylation
addition of carboxylic acid groups
101
glycosylation
addition of oligosaccharides (sugars), completed in golgi body
102
preenylation
addition of lipid groups, allowing for incorporation of the protein into membranes
103
eukaryotic transcription
occurs in the nucleus.
monocistronic mRNA transcripts
104
prokaryotic transcription
occurs in the cytoplasm.
posttransciptional modification cannot occur.
polycistronic mRNA transcipts
105
proteins
formed by the culmination of transcription & translation, proteins are functional units of life. vast majority of all cellular functions are completed by proteins
106
4 levels of protein structure
primary, secondary, tertiary, and quarternary
107
primary structure protein
sequence of amino acids listed from N-terminus to the C-terminus. peptide bonds are central to protein's primary structure
108
secondary structure protein
local 3D structure of neighboring amino acids. most common ones are alpha helices and beta sheets.
the stability relies on H bond formation b/w amino acid side chains
109
tertiary structure of protein
folding of polypeptide forming the 3D structure of the entire protein.
folding is assisted by chaperones.
relies on hydrophobic & hydophillic interactions of amino acid side groups and disulfide bonds
110
chaperones
cellular proteins that stabilize transition states in the folding process
111
quaternary structure of proteins
combining of polypeptides to form a complete protein complex.
stability relies on both hydrophobic and hydrophillic interactions and disulfide bonds.
Not all proteins have a quaternary structure.
112
2 major categories of proteins
enzymatic or non-enzymatic
113
non-enzymatic categories
structural proteins or binding proteins
114
structural proteins
function to fix cellular components in place or move cellular components to needed location.
like cytoskeleton or motor proteins
115
binding proteins
serve to transport, attach, or sequester molecules by directly adhering to the molecule
116
ezymes
proteins w/ catalytic function
117
catalyst
any substance that affects the rate of a chemical reaction while remaining unchanged or being regenerated as a product
118
conjugated proteins
covalently bond to other groups that often serve as coenzymes of cofactors
119
substrate
molecule that the enzyme acts on
120
active site
area on which substrate binds on each enzyme
121
most enzyme-catalyzed reactions are reversible
product synthesized by an enzyme can be reversed by the same enzyme
122
characteristics of enzymes
- do not alter eq. constant
- not consumed in the reaction
- lower activation energy
- pH & temp sensitive
123
lock and key theory
holds that the spatial structure of an enzymes active site is exactly complementary to the spatial structure of its substrate
124
induced fit theory
the active site has flexibility of shape
125
enzyme action and reaction rate depends on
temperature, pH, and the concentration of the enzyme & substrate
126
competitive inhibition
if a similar molecule is present in a concentration comparable to the concentration of the substrate, it will compete with the substrate for binding sites on the enzyme & interfere w/ enzyme activity
127
noncompetitive inhibitor
a substance that binds to an enzyme at a site other than the active site
128
allosteric site
- "other site or structure"
- resulting in a nonfunctional active site
- allosteric inhibition
129
ligases
catalyze addition or synthesis reactions, generally b/w large similar molecules and often require ATP.
most likely to be encountered in nucleic acid synthesis and repair.
help in joining (ligating) 2 molecules by forming chemical bonds
130
isomerases
catalyze the rearrangement of bonds w/in a molecule.
catalyze reactions b/w stereoisomers as well as constitutional isomers
131
lyases
catalyze the cleavage of a single molecule into 2 products
132
synthases
synthesis of 2 small molecules into a single molecule by catalyzed by lyase
133
hydrolases
catalyze the breaking of a compound into 2 molecules using the addition of water.
common one is phosphatase
134
phosphatase
cleaves a phosphate group from another molecule
135
peptidases
break down proteins
136
nucleases
break down nucleic acids
137
lipases
break down lipids
138
oxidoreductases
catalyze oxidation reduction reactions - transfer of electrons b/w bio molecules.
often have a cofactor that acts as an electron carrier like NAD+ or NADP+.
reductant = electron donor
oxidant = electron acceptor
139
oxidase
enzyme in which oxygen is the final electron acceptor
140
transferases
catalyze the movement of a functional group from one molecule to another
141
kinases
catalyze the transfer of a phosphate group, generally from atp to another molecule
142
metabolism
sum of all chemical reactions that occur in the body
143
catabolic reactions
break down chemicals & release energy
144
anabolic reactions
synthesize chemicals and require energy
145
cellular respiration
describes the biochemical conversion of chemical energy stored in molecular bonds into usable energy (ATP), a catabolic process
146
2 major pathways of cellular respiration
aerobic & anerobic
147
aerobic respiration
occurs in the presence of oxygen
148
anerobic respiration
occurs in the absence of oxygen
149
external respiration
refers to the inhaling & exhaling of air into and out of the lungs as well as the exchange of gas b/w alveoli and the blood
150
internal respiration
refers to exchange of gas b/w individual cells and the extracellular fluid
151
if energy is released during a reaction ...
... then the products must have less potential energy than reactants
152
why are carbohydrates and fats favored fuel molecules?
due to their high # of energy rich C-H bonds
153
how does cellular respiration release energy
in a series of small steps
allows the cell to capture energy for use
154
what does the degradation of glucose by oxidation begin with?
glycolysis
155
2 separate pathways of glucose catabolism
aerobic and anerobic
156
glycolysis
"sugar breaking"
series of reactions that lead to the oxidative breakdown of glucose into 2 molecules of pyruvate, the production of ATP, and the reduction of NAD+ and NADH
157
where does glycolysis occur?
the cytoplasm
158
early investment stage of glycolysis
steps 1-3
2 ATPs are used to add 2 phosphate groups to glucose
produces fructose 1,6-biphosphate
completed by kinases
159
cleavage stage of glycolysis
step 4
splits fructose 1,6-biphosphate into glyceraldehyde 3-phosphate (PGAL) and dihydroxyacetone phosphate (DHAP)
DHAP is then isomerized to form a second PGAL
160
energy payout stage of glycolysis
steps 5-9
results in the production of ATP
these steps occur twice per glucose molecule
PGAL is converted to pyruvate resulting in the reduction of NAD+ to NADH (catalyzed by a dehydrogenase) and the production of 2 ATPs (catalyzed by kinases)
161
from one molecule of glucose (6C) ...
2 molecules of pyruvate (3C) are obtained
162
substrate level phosphorylation
ATP synthesis is directly coupled with the oxidation of glucose w/out participation of an intermediate molecule such as NADH or FADH2
163
oxidative phosphorylation
requires an intermediate electron carrier such as NADH or FADH2
164
pyruvate degradation under anaerobic conditions
pyruvate is reduced during the process of fermentation
165
pyruvate degradation under aerobic conditions
pyruvate is further oxidized during cellular respiration in the mitochondria
166
alcohol fermentation
occurs in yeast and some bacteria
pyruvate produces in glycolysis is converted to ethanol
NAD+ is regenerated and glycolysis can continue
167
lactic acid fermentation
occurs in certain fungi, bacteria, and in human muscle cells during strenuous activity
pyruvate generated is reduced to lactic acid
NAD+ is regenerated when pyruvate is reduced
168
aerobic respiration can yield ...
36-38 ATP
169
anaerobic respiration yields ...
2 ATP
170
where do aerobic respiration stages occur?
eukaryotes: mitochondria
prokaryotes: cytoplasm
171
pyruvate decarboxylation
stage of aerobic respiration
produces Acetyl-CoA
172
citric acid cycle (aka krebs cycle)
stage of aerobic respiration
Acetyl-CoA undergoes a cycle of reactions producing electron carriers (NADH, FADH2) and regenerating oxaloacatate, allowing the cycle to repeat
173
electron transport chain
stage of aerobic respiration
located in mitochondrial membrane, which transports protons against their concentration gradient into the inter-membrane space
174
cytochromes
electron carriers that resemble hemoglobin in the structure of their active site
most of the molecules in the electron transport chain
175
where is the electron transport chain located?
inside of the inner mitochondrial membrane
176
proton gradient
the coupling agent for oxidation of NADH & FADH2 to the phosphorylation of ADP across the inner mitochondrial membrane
177
oxidative phosphorylation
the coupling of the oxidation of NADH and FADH2 with the phosphorylation of ADP
178
net total amount of ATP produced per molecule of glucose
number of ATP produced by substrate level phosphorylation + the number of ATP produced by oxidative phosphorylation
179
substrate level phosphorylation
4 total ATP produced
2 ATP from glycolysis
1 ATP from each turn of the citric acid cycle
180
oxidative phosphorylation
32 ATP produced
(34 for prokaryotes)
181
preferential order of use of alternate energy sources
other carbohydrates
fats
proteins
182
how are alternate energy sources converted?
first converted to either glucose or glucose intermediaries, which can then be degraded in the glycolytic pathway and citric acid cycle
183
fats
molecules stored in adipose tissue in the form of triglycerides
184
conversion of fats when necessary
hydrolyzed by lipases to fatty acids and glycerol & are carried to the blood to other tissues for oxidation
185
which high energy compound used in cellular respiration yields the greatest # of ATP per gram?
fats
makes them extremely efficient energy storage molecules
186
transamination reaction
proteins lose an amino group to form an a-keto acid
187
what are most carbon atoms from most amino acids converted into?
acetyl-CoA, pyruvate, or one intermediates of the citric acid cycle
188
when the intermediaries enter their respective pathways, what are cells able to produce?
fatty acids, glucose, or energy in the form of ATP
189
oxidative deamination
removes an ammonia molecule directly from the amino acid
190
ammonia
toxic substance in vertebrates
191
photosynthesis
plants use it to convert carbon dioxide and water into glucose and oxygen
involves the reduction of CO2 to carbohydrate accompanied by release of oxygen from water
192
where does photosynthesis takes place?
in the chloroplast
193
photosynthesis light reactions (aka photolysis reactions)
require sunlight
absorption of a photon of light by a chlorophyll molecule which excites electrons to a higher energy level
can flow along cyclic electron flow or noncyclic electron flow
194
photosynthesis dark reactions
do not require sunlight
195
cyclic electron flow
excited electrons of P700 move along a chain of electron carriers. a series of redox reactions ultimately returns the electrons to P700
uses electron transpot chain, a proton gradient, and ATP synthase to produce ATP from ADP
196
cyclic photophosphorylation
process used to produce ATP from ADP
197
noncyclic electron flow
photons of light excite electrons in P700 in photosystem I, and then electrons are transferred to the electron acceptor NADP+
198
dark reactions
use ATP and NADPH produced by light reactions to reduce CO2 to carbohydrates
199
genetics
study of how traits are inherited from one generation to the next
200
gene
basic unit of heredity
composed of DNA and are located on chromosomes
201
alleles
alternative form of a gene that exists in multiple forms
202
genotype
genetic makeup of an individual
203
phenotype
physical manifestation of the genetic makeup
204
Mendel's 4 principles of inheritance
1. genes exist in alternative forms. a gene controls a specific trait in an organism
2. an organism has 2 alleles for each inherited trait, one inherited from each parent.
3. the 2 alleles segregate during meiosis, resulting in gametes that carry only one allele for any given individual trait
4. if 2 alleles in an individual org are different, only 1 will be fully expressed. a dominant allele only requires one copy present to be expressed whereas a recessive allele must have 2 copies present to be expressed.
205
homozygous
contain 2 copies of the same allele
206
heterozygous
carry 2 different alleles
207
mendel's law of dominance
dominant allele is expressed in the phenotype
208
monohybrid cross
only one trait is being studied in a particular mating
209
parental or P generation
the individuals being crossed
210
filial or F generations
the progeny generations
each generation is numbered sequentially
211
testcross
a dx tool used to determine the genotype of an organism
212
mendel's law of independent assortment
the alleles of two (or more) different genes get sorted into gametes independently of one another
213
crossing over
exchanges info b/w chromosomes and may break the linkage of certain patterns
214
codominance
occurs when multiple alleles exist for a given gene and more than one of them is dominant
both alleles in the genotype are expressed at the same time w/out a blending of phenotype
215
incomplete dominance
the phenotype expressed is a blend of both genotypes
216
sex linked
genes located on the X or Y chromosome
217
nondisjunction
failure of homologous chromosomes to separate properly during meiosis I or the failure of sister chromatids to separate properly during meiosis II
218
trisomy
zygote having 3 copies of chromosome
down syndrome - trisomy 21
219
monosomy
zygote having a single copy of chromosome
turner's syndrome - only viable monosomy
220
mutations
changes in the genetic information coded in the DNA of a cell
221
mutations in somatic cells
can lead to tumors
222
mutations in sex cells
will be passed to offspring
223
mutagenic agents
induce mutations
224
point mutation
a nucleic acid is replaced by another nucleic acid
225
codon
sequence of 3 nucleotides that determines the identity of the amino acid
226
a silent mutation
the new codon may code for the same amino acid
no change in the resulting protein
227
a missense mutation
the new codon may code for a different amino acid
may lead to a problem with the resulting protein, depending on the role of that amino acid
228
a nonsense mutation
the new codon may be a stop codon
often lethal or severely inhibit the functioning of the protein
229
frameshift mutation
nucleic acids are deleted or inserted into the genome sequence
frequently is lethal
230
bacterial genome
consists of a single circular chromosome located in the nucleoid region of the cell
231
plasmids
smaller circular rings of DNA that contain accessory genes
232
episomes
plasmids that are capable of integration into the bacterial genome
233
replication of bacterial chromosome
begins at a unique origin & proceeds in both directions simultaneously
DNA is synthesized in the 5' to 3' direction
234
3 mechanisms of bacteria for increasing the genetic variation
transformation
conjugation
transduction
235
binary fission
how bacterial cells reproduce
an asexual process
236
transformation
process by which a foreign chromosome fragment (plasmid) is incorporated into the bacterial chromosome via recombination, creating new inheritable genetic combos
237
conjugation
sexual mating in bacteria
transfer of genetic material b/w 2 bacterial temporarily joined
genetic material is transferred from male to female
238
F factor
in e coli
best studied sex factor
239
Hfr cells
high frequency of recombination
240
bacteriophage
a virus that infects its host bacterium by attaching to the bacterium, boring a hole thru a bacterial cell wall, and injecting its viral DNA while its protein coat remains attached to the cell wall
241
transduction
when fragments of the bacterial chromosome become packaged into the viral progeny produced during such a viral infection
closer 2 genes are to one another on a chromosome, the more likely they will be to transduce together
242
recombination
occurs when linked genes are separated
occurs by breakage & rearrangement of adjacent regions of DNA when organisms are carrying different genes or alleles for the same traits are crossed
243
operator
the sequence of nontranscribable DNA that is the repressor binding site
244
promoter
the noncoding sequence of DNA that serves as the initial binding site of the RNA polymerase
245
regulator gene
codes for the synthesis of a repressor molecule that binds to the operator & blocks RNA polymerase from transcribing structural genes
246
inducible systems
those that require the presence of a substance, called an inducer, for transcription to occur
247
repressible systems
in a constant state of transcription unless corepresssor is present to inhibit transcription
248
pedigrees
tools used by geneticists to track 1 phenotype in a family across generations
males are squares, females are circles
affected are shaded in, unaffected are not
249
autosomal recessive
a person will only be affected if he or she possesses 2 copies of the recessive allele (homozygous recessive)
can skip generations
250
autosomal dominant
a person will be affected if he or she possesses one or more copies of the dominant allele (heterozygous or homozygous dominant)
will appear in every generation
251
evolution
change in genetic makeup of a population with time
252
acquired characteristics
any useful characteristic acquired in 1 generation was thought to be transmitted to the next
has been disproven by modern genetics
253
fitness
ability to survive and reproduce
254
natural selection
Darwin's theory
nature selects the best set of parents for the next generation
255
overpopulation
more offspring are produced than can survive
food, air, light, and space are insufficient to support the entire population
256
variations
offspring naturally show differences in their characteristics compared to those of their parents
257
competition
developing population must compete for the necessities of life
many young must die, and the # of adults in the population generally remains constant from generation to generation
258
inheritance of the variations
the individuals that survive live to adulthood to reproduce and thus transmit these favorable variations or adaptations to their offspring
favored genes gradually dominate the gene pool
259
evolution of new species
the favorable changes are perpetuated in the species
results in significant changes in the gene pool that we can say a new species has evolved
changes perpetuated or selected for by environmental conditions
260
speciation
evolution of new species
261
demes
before speciation
formation of small, local populations w/in a species
if they become isolated, speciation can occur
262
phylogeny
evolutionary history
263
clade
all descendants from the common ancestor
264
convergent evolution
2 species from different ancestors develop similar traits
265
parallel evolution
similar to convergent evolution
occurs when a more recent ancestor can be identified
266
