DAT prep 2022 QUESTIONS AND ANSWERS
Lamarck's Theories ANS: 1. Use and Disuse: Increase usage, increase development.
2. Inheritance of Acquired Characteristics: Acquired body features developed during lifetime (Muscle
Build) passed to offspring. (FALSE)
3. Natural Transformation of Species: Increasing complexity and greatness (FALSE)
Palentology ANS: Study of fossils that reveal existence of extinct species.
Deeper the fossil, the older.
Biogeography ANS: Study of how geography shows the distribution of a species. (Unrelated species in
different areas containing similar appearance)
Embryology ANS: Shows similar stages of development (Ontogeny)
Similarities develop phylogeny.
Comparative Anatomy ANS: Uses homologous structures and analogous structures to demonstrate
evolution.
Homologous: Evolution from a common ancestor. (Similar structure due to similar ancestor)
Analogous: Demonstrates similar adaptations. (Similar structure but not from similar ancestor)
Molecular Biology ANS: Examines nucleotide and amino acid sequence of DNA and proteins to compare
to other species.
Natural Selection ANS: The adaptations of a species due to pressures from the environment. (Increases
beneficial traits, decreases unbeneficial traits.) - Reproductive potential, population size is stable,
resources are limited, species compete for survival, variation among individuals, variation is heritable.
Stabilizing Selection ANS: Eliminates extreme traits. (Most common become more common
Directional Selection ANS: One side of extremes is selected against (Pushes to other extreme)
Sexual Selection ANS: - Females increase quality of males as mates (Female Choice)
- Contests among men for mates. (Male Competition)
Artificial Selection ANS: When humans breed animals (Not natural selection)
Sources of Variation ANS: 1. Mutations
2. Sexual Reproduction (Crossing Over, Independent Assortment, and Random Gamete joining)
3. Diploidy (Heterozygotes different than homozygotes)
4. Outbreeding (Mating outside related individuals)
5. Balanced Polymorphism (Advantageous heterozygotes, Hybrid Vigor (Inbred strains crosseed), and
Frequency-dependent selection (Least common doesn't get eaten as much because not usual)
Gene Flow ANS: Addition or removal of alleles due to emigration or immigration.
Genetic Drift ANS: Random increase/decrease in alleles
,Founder Effect: Migrating individuals don't have same allele frequencies of their previous population.
Bottleneck: Dramatic Decrease in size changing allele frequencies
Genetic Equilibrium (Hardy-Weinberg Equilibrium) ANS: 1. All traits are selectively neutral.
2. No Mutations.
3. Population isolated from other populations.
4. Population is large.
5. Mating is random. NNPLR (nonpolar)
Allopatric Speciation ANS: Geographic barrier separataing a population in two or more. Then allele
frequencies change due to natural selection.
Sympatric Speciation ANS: Can be caused by balanced polymorphism, polyploidy (plants), and
hybridization.
Adaptive Radiation ANS: Rapid evolution of a species from a single ancestor (Ancestral species placed in
colonbizable location.)
Types of reproductive isolation ANS: 1. Habitat
2. Temporal
3. Behavorial
4. Mechanical
5. Gametic
6. Hybrid Inviability
7. Hybrid Sterility
8. Hybrid Breakdown (Reduced Viability/Fertility)
Divergent Evolution ANS: Two species that become different that came from a common ancestor
Convergent Evolution ANS: Two unrelated species that develop analogous traits that make them similar
to eachother.
Parallel evolution ANS: Two species that are related that undergo similar mutations after diverging from
common ancestor
Coevolution ANS: Predator and prey evolving according to one another
Macroevolution Theories ANS: - Phyletic Gradualism - Gradual accumulation of small changes evolving
an organism.
- Punctuacted Equilibrium - Long stasis then short periods of rapid evolution.
Origin of life ANS: 1. Earth and atmosphere
2. Seas formed
3. Complex molecules synthesized
4. Polymers made
5. Protobions (Precursor of cell) concentrated these molecules.
6. Heterotrophic prokaryotes formed.
7. Autotrophic prokaryotes formed.
,8. Oxygen and ozone layter formed
9. Eukaryotes formed (Endosymbiotic Theory)
Endosymbiotic Theory ANS: Mitochondria, Chloroplats, and other organelles took resident in a
prokaryote.
Evidence:
Mitochondria/Chloroplasts have their own naked, circular DNA They reproduce independently of the
cell.
They have the similar ribosomes as bacteria and cyanobacteria
They have two membranes (Second probably developed by endocytosis)
Thylakoid membranes of chloroplasts resemble membranes of cyanobacteria.
Miller-Urey experiment ANS: Showed that water, hydrogen, ammonia, and methane could be heated
and form organic molecules (Including aminio acids)
Analogous Structures ANS: Structures that perform the same function that are on animals with different
ancestry
Homologous structures ANS: Structures that might perform the same function but have the same
ancestry.
Vestigal Structures ANS: A structure that once had function in an ancestor but no longer do.
- These structures remain due to lack of selection pressure.
Gene ANS: The DNA that has the instructions for a particular trait
Allele ANS: One of several variations of a gene
Locus ANS: The location on a chromosome where a gene is located.
Homologous Chromosomes ANS: A pair of chromosomes that contain the same genes. (Not alleles)
Phenotype ANS: The expression of a trait from a gene
Genotype ANS: The part of chromosome that codes for a trait (Ex: Pp)
Law of Segregation ANS: Alleles segregate to different gametes. Making each gamete contain only 1 of
each chromosome
Law of Independent Assortment ANS: The migration of one pair of homologues to different poles
doesn't effect the migration of another pair of homologues.
Hybrid Cross ANS: The mating of things expressing different traits.
Monohybrid Cross ANS: Experiment where one trait is investigated.
Dihybrid Cross ANS: Experiment where two traits are investigated.
, Complete Dominance ANS: If the one allele is present in the genotype, it expresses dominace fully.
Test Cross ANS: Crossing a known genotyped organism with an unknown one to find the genotype.
Incomplete Dominance ANS: Expression of gene varies with degrees according to if it is
homo/heterozygous
RR = Red
Rr = Pink
rr = White
Codominance ANS: Both alleles of a gene are completely expressed in the phenotype. RBCs
Epistasis ANS: When one gene affects the phenotypic expression of a second gene.
Ex: 1st Gene: On/Off gene, 2nd Gene: Hair Color Expression
Pleiotropy ANS: When one gene has more than one phenotypic expression.
Ex: The gene in pea plants that effect wrinkled/round also effects starch production and water
concentration.
Polygenic Inheritance ANS: Many genes affecting a certain phenotype (Height)
Linked Genes ANS: Gene that are on the same chromosome
- Increases the liklihood that they will be in the same gamete.
- The further the distance on the chromosome, the more likely they will be segregated. 18% crossing
over = 18 Map units (Linkage Map)
Sex-Linked Inheritance ANS: When genes are on the X or Y (Not likely) chromosome, it makes dominant
and recessive genes affect males.
Ex: Hemophilia
X-Inactivation ANS: In females, when one of the X chromosomes does not uncoil into chromatin (Barr
body). Causes X linked diseases to more easily effect women.
- Sometimes is splotchy throughout their bodies.
- Sometimes is general
Nondisjunction ANS: Failure of chromosomes pairs or chromatids of a single chromosome type to
properly separate during meiosis/mitosis.
Polyploidy ANS: When ALL of the chromosomes undergo meiotic nondisjunction.
- Producing gametes with twice the # of chromosomes.
Mitotic Nondisjuction Issues (Result in Mosaicism) ANS: Only occur during embryonic development,
causing a fraction of the cells to contain too many/not enough chromosomes.
Meiotic Nondisjunction ANS: Failure of two homologues (Anaphase I) or two sister chromatids
(Anaphase II) to separate.
- Cauing gametes to have too many/not enough chromosomes.
Lamarck's Theories ANS: 1. Use and Disuse: Increase usage, increase development.
2. Inheritance of Acquired Characteristics: Acquired body features developed during lifetime (Muscle
Build) passed to offspring. (FALSE)
3. Natural Transformation of Species: Increasing complexity and greatness (FALSE)
Palentology ANS: Study of fossils that reveal existence of extinct species.
Deeper the fossil, the older.
Biogeography ANS: Study of how geography shows the distribution of a species. (Unrelated species in
different areas containing similar appearance)
Embryology ANS: Shows similar stages of development (Ontogeny)
Similarities develop phylogeny.
Comparative Anatomy ANS: Uses homologous structures and analogous structures to demonstrate
evolution.
Homologous: Evolution from a common ancestor. (Similar structure due to similar ancestor)
Analogous: Demonstrates similar adaptations. (Similar structure but not from similar ancestor)
Molecular Biology ANS: Examines nucleotide and amino acid sequence of DNA and proteins to compare
to other species.
Natural Selection ANS: The adaptations of a species due to pressures from the environment. (Increases
beneficial traits, decreases unbeneficial traits.) - Reproductive potential, population size is stable,
resources are limited, species compete for survival, variation among individuals, variation is heritable.
Stabilizing Selection ANS: Eliminates extreme traits. (Most common become more common
Directional Selection ANS: One side of extremes is selected against (Pushes to other extreme)
Sexual Selection ANS: - Females increase quality of males as mates (Female Choice)
- Contests among men for mates. (Male Competition)
Artificial Selection ANS: When humans breed animals (Not natural selection)
Sources of Variation ANS: 1. Mutations
2. Sexual Reproduction (Crossing Over, Independent Assortment, and Random Gamete joining)
3. Diploidy (Heterozygotes different than homozygotes)
4. Outbreeding (Mating outside related individuals)
5. Balanced Polymorphism (Advantageous heterozygotes, Hybrid Vigor (Inbred strains crosseed), and
Frequency-dependent selection (Least common doesn't get eaten as much because not usual)
Gene Flow ANS: Addition or removal of alleles due to emigration or immigration.
Genetic Drift ANS: Random increase/decrease in alleles
,Founder Effect: Migrating individuals don't have same allele frequencies of their previous population.
Bottleneck: Dramatic Decrease in size changing allele frequencies
Genetic Equilibrium (Hardy-Weinberg Equilibrium) ANS: 1. All traits are selectively neutral.
2. No Mutations.
3. Population isolated from other populations.
4. Population is large.
5. Mating is random. NNPLR (nonpolar)
Allopatric Speciation ANS: Geographic barrier separataing a population in two or more. Then allele
frequencies change due to natural selection.
Sympatric Speciation ANS: Can be caused by balanced polymorphism, polyploidy (plants), and
hybridization.
Adaptive Radiation ANS: Rapid evolution of a species from a single ancestor (Ancestral species placed in
colonbizable location.)
Types of reproductive isolation ANS: 1. Habitat
2. Temporal
3. Behavorial
4. Mechanical
5. Gametic
6. Hybrid Inviability
7. Hybrid Sterility
8. Hybrid Breakdown (Reduced Viability/Fertility)
Divergent Evolution ANS: Two species that become different that came from a common ancestor
Convergent Evolution ANS: Two unrelated species that develop analogous traits that make them similar
to eachother.
Parallel evolution ANS: Two species that are related that undergo similar mutations after diverging from
common ancestor
Coevolution ANS: Predator and prey evolving according to one another
Macroevolution Theories ANS: - Phyletic Gradualism - Gradual accumulation of small changes evolving
an organism.
- Punctuacted Equilibrium - Long stasis then short periods of rapid evolution.
Origin of life ANS: 1. Earth and atmosphere
2. Seas formed
3. Complex molecules synthesized
4. Polymers made
5. Protobions (Precursor of cell) concentrated these molecules.
6. Heterotrophic prokaryotes formed.
7. Autotrophic prokaryotes formed.
,8. Oxygen and ozone layter formed
9. Eukaryotes formed (Endosymbiotic Theory)
Endosymbiotic Theory ANS: Mitochondria, Chloroplats, and other organelles took resident in a
prokaryote.
Evidence:
Mitochondria/Chloroplasts have their own naked, circular DNA They reproduce independently of the
cell.
They have the similar ribosomes as bacteria and cyanobacteria
They have two membranes (Second probably developed by endocytosis)
Thylakoid membranes of chloroplasts resemble membranes of cyanobacteria.
Miller-Urey experiment ANS: Showed that water, hydrogen, ammonia, and methane could be heated
and form organic molecules (Including aminio acids)
Analogous Structures ANS: Structures that perform the same function that are on animals with different
ancestry
Homologous structures ANS: Structures that might perform the same function but have the same
ancestry.
Vestigal Structures ANS: A structure that once had function in an ancestor but no longer do.
- These structures remain due to lack of selection pressure.
Gene ANS: The DNA that has the instructions for a particular trait
Allele ANS: One of several variations of a gene
Locus ANS: The location on a chromosome where a gene is located.
Homologous Chromosomes ANS: A pair of chromosomes that contain the same genes. (Not alleles)
Phenotype ANS: The expression of a trait from a gene
Genotype ANS: The part of chromosome that codes for a trait (Ex: Pp)
Law of Segregation ANS: Alleles segregate to different gametes. Making each gamete contain only 1 of
each chromosome
Law of Independent Assortment ANS: The migration of one pair of homologues to different poles
doesn't effect the migration of another pair of homologues.
Hybrid Cross ANS: The mating of things expressing different traits.
Monohybrid Cross ANS: Experiment where one trait is investigated.
Dihybrid Cross ANS: Experiment where two traits are investigated.
, Complete Dominance ANS: If the one allele is present in the genotype, it expresses dominace fully.
Test Cross ANS: Crossing a known genotyped organism with an unknown one to find the genotype.
Incomplete Dominance ANS: Expression of gene varies with degrees according to if it is
homo/heterozygous
RR = Red
Rr = Pink
rr = White
Codominance ANS: Both alleles of a gene are completely expressed in the phenotype. RBCs
Epistasis ANS: When one gene affects the phenotypic expression of a second gene.
Ex: 1st Gene: On/Off gene, 2nd Gene: Hair Color Expression
Pleiotropy ANS: When one gene has more than one phenotypic expression.
Ex: The gene in pea plants that effect wrinkled/round also effects starch production and water
concentration.
Polygenic Inheritance ANS: Many genes affecting a certain phenotype (Height)
Linked Genes ANS: Gene that are on the same chromosome
- Increases the liklihood that they will be in the same gamete.
- The further the distance on the chromosome, the more likely they will be segregated. 18% crossing
over = 18 Map units (Linkage Map)
Sex-Linked Inheritance ANS: When genes are on the X or Y (Not likely) chromosome, it makes dominant
and recessive genes affect males.
Ex: Hemophilia
X-Inactivation ANS: In females, when one of the X chromosomes does not uncoil into chromatin (Barr
body). Causes X linked diseases to more easily effect women.
- Sometimes is splotchy throughout their bodies.
- Sometimes is general
Nondisjunction ANS: Failure of chromosomes pairs or chromatids of a single chromosome type to
properly separate during meiosis/mitosis.
Polyploidy ANS: When ALL of the chromosomes undergo meiotic nondisjunction.
- Producing gametes with twice the # of chromosomes.
Mitotic Nondisjuction Issues (Result in Mosaicism) ANS: Only occur during embryonic development,
causing a fraction of the cells to contain too many/not enough chromosomes.
Meiotic Nondisjunction ANS: Failure of two homologues (Anaphase I) or two sister chromatids
(Anaphase II) to separate.
- Cauing gametes to have too many/not enough chromosomes.
