Bio Lec Exam 1

Front 1

Autotroph

Back 1

an organism capable of producing its own organic compounds from inorganic materials (such as photosynthesis)

Front 2

Coacervate

Back 2

a specific type of protobiont containing enzymes used for more complex synthesis

Front 3

Endomembranous theory

Back 3

single membrane organelles originated by budding off the internal surface of the plasma membrane

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Endosymbiont

Back 4

an organism that lives in or on another

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Endosymbiosis theory

Back 5

double membrane organelles arose from a symbiotic relationship in which the endosymbiont living inside the cell lost its autonomy and became incorporated as an organelle within that cell

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Heterotroph

Back 6

an organism not capable of producing its own organic molecules from inorganic materials (will be a consumer)

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Microsphere

Back 7

one type of protobiont; produced by adding water to abiotically formed polypeptides

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Protobiont

Back 8

a vesicle of abiotically produced polymers

Front 9

Stromatolite

Back 9

a column of prokaryote cells that become fossilized (living ones are extremely rare)

Front 10

Describe the early conditions on early Earth and the requirements for life to begin.

Back 10

I. Environment and evolution of organic molecules: gases present in primitive atmosphere- CO2, H2O, CO, N2, H2S, CH4

II. 4 requirements for chemical evolution:

1. Little or no free oxygen so atmosphere was reducing environment

2. Energy source was lightning, cosmic and ultraviolet radiation

3. Chemical building blocks including water, dissolved inorganic molecules and atmospheric gases were present

4. Time

Front 11

Describe how naturally occurring surfaces may have contributed to early chemical reactions and compare and contrast prebiotic soup hypothesis with iron-sulfur hypothesis for the evolution of protobionts and cells.

Back 11

I. Formation of organic molecules

A. Reactive surfaces

1. Pyrite

2. Clay

-Charged surfaces (attract/repel objects together); ions (catalysts) (iron and zinc)- attracting molecules together, reaction occurs, something is synthesized; enzyme-like features

B. Prebiotic soup near Earth's surface: organic molecules formed near Earth's surface in "sea of organic soup"

C. Iron-sulfur hypothesis

1. Organic precursors formed near thermal vents: energy-rich molecules and precursors of biological molecules

2. Communities there today: tube worms and other organisms (lots of life)

Front 12

Describe the Miller-Urey experimental model and explain how it could be used to investigate the synthesis of organic molecules.

Back 12

I. Miller-Urey experiments

A. Conditions meant to mimic primitive Earth

B. Results: all 20 amino acids, bases for RNA and DNA, lipids, ATP, etc. based upon what is in the mixture that is used

Front 13

Define the terms associated with evolution of early life (anaerobe, aerobe, heterotroph, autotroph)

Back 13

A. Anaerobic: survive in absence of oxygen (oxygen not an electron acceptor)

B. Aerobe: requires oxygen

C. Heterotroph: ingests previously formed organic and inorganic material; rely on other organisms

D. Autotroph: synthesize own organic nutrients from inorganic molecules

Front 14

Describe the requirements preceding the origin of cells and life.

Back 14

A. Abiotic production of nucleotides and amino acids

B. Polymerization leading to DNA, RNA, and amino acids

C. 2 types of microspheres formed

1. Protobionts

2. Coacervates

D. Membrane enclosed polymers (coacervates) evolved cellular properties

1. Self-replication

2. Inheritance

Front 15

Compare and contrast protobionts, microspheres, and coacervates, and discuss their relationship to the hypothesis of pre-cell life.

Back 15

I. Microspheres as precursors to cells: protobionts and coacervates

A. Protobionts: nonliving structures (spheres) that evolved into cells (spontaneously formed from environment); separate internal and external environments (ability to isolate); excitable (stimulate sphere to make things happen; electrochemical gradients); osmotically active (diffusion; things can leave and come back; respond to osmotic and chemical changes in environment); simple chemical reactions (what's inside determines results and location of reaction-spontaneous); division (like soap bubbles; not metabolic; spontaneous; binary fission-protists); no DNA to establish linkage; no self-replication

B. Coacervates leading to first cells: specialized microspheres with organic molecules trapped inside (primitive with cell-like structures); if enzymes are trapped inside, reactions can occur (formation of sugar)

Front 16

Outline the major steps hypothesized to have occurred in the origin of cells and discuss which order might be correct.

Back 16

A. Metabolism- first hypothesis- benefits of chemical reactions

1. Intrasphere organization: reactions with coacervates result in more intrapshere organization and function

2. Energy source: intrasphere energy source coupled to reactions is possible (ATP to ADP)

3. RNA and DNA synthesis: already knew they can form spontaneously on clay; proteins (enzymes) first would allow organized synthesis of RNA and DNA

B. RNA-first hypothesis

1. Self-replicating RNA arose first: enzymatic RNA, ribozymes (enzymes) drove RNA replication and eventually chemical reactions in cells

2. Role for proteins: later protein enzymes took on role catalyzed reactions

3. Information storage: RNA can store information in its sequence

C. DNA involvement in cellular processes

1. Initial DNA synthesis: RNA replicated a duplicate strand; DNA made from RNA via reverse transcription

2. Positives for evolution of DNA: DNA is better for storage, double-stranded (less mutations), information stability/ important for transferring information, fewer mutations than single stranded RNA

3. Negative for DNA synthesis first: no enzymatic properties

D. Transition from RNA/DNA/protein to DNA/RNA/protein world

- DNA became the information storage molecule

- RNA remained involved in protein synthesis

- Protein enzymes catalyzed most cell reactions

- Selection occurred for cells with both DNA and RNA

Front 17

Describe stromatolites and discuss their significance in the evolution of early cells.

Back 17

A. Stromatolites

1. Microfossils

2. Minute layers of prokaryotic cells (Cyanobacteria)

3. Fossil evidence of early cells 3.5 bya

4. Some still living

B. Cyanobacteria: these organisms were most likely the source of the first free oxygen in the atmosphere

Front 18

Describe the first cells and the transformation from an anaerobic to an aerobic environment.

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I. Survival of the first cells

A. Heterotrophs: require energy source in highly reductant atmosphere; limits types of chemical reactions possible

B. Anaerobic environment: almost certainly obtained energy through fermentation

C. Energy source fermentation

II. Transition from heterotroph to autotroph

A. Switch from fermentation to photosynthesis: eventually organisms that could obtain energy from other sources evolved and survived; mutations likely permitted some cells to obtain energy directly from sunlight

B. Splitting molecules other than water: perhaps splitting hydrogen-rich molecules, such as H2S releasing sulfur (easier to split than water)

C. Role of cyanobacteria and photosynthesis: cyanobacteria- first organisms to obtain hydrogen electrons by splitting water; photosynthesis- released oxygen as a gas, which oxidized other molecules and increased oxygen levels in the ocean and atmosphere

Front 19

Compare and contrast the autogenesis (endomembranous) and serial endosymbiosis theories relating them to the evolution of eukaryotic cells and cellular organelles and discuss evidence that organelles arose from an endosymbiotic relationship with eubacteria.

Back 19

I. Origin of organelles

A. Autogenesis (endomembranous) theory: single membrane organelles; inward budding of plasma membrane

B. Serial endosymbiosis: early eukaryotic cells- assemblages of once free-living prokaryotes; chloroplasts evolved from photosynthetic bacteria engulfed by heterotrophic cells; mitochondria evolved from bacteria initially engulfed by anaerobic cells

II. Origin of organelles: evidence supporting prokaryotic origin of some cellular organelles

A. Size: similar

B. Genetic analysis: indicate mitochondria were derived from bacterium similar to modern alpha proteobacteria that synthesis ATP via oxidative phosphorylation

C. Enzymes and transport systems

D. Replication: similar- binary fission or splitting

E. Antibiotics: organelle activities harmed by antibiotics that work against bacteria

Front 20

Convergent evolution

Back 20

organisms evolved similar characteristics as a result of exposure to similar environmental challenges (natural selection)

Front 21

Macroevolution

Back 21

major evolutionary changes that occur over a long period of time resulting in large phenotypic changes such as the formation of new species

Front 22

Microevolution

Back 22

more minor evolutionary changes that occur over just a few generations

Front 23

Modern synthesis

Back 23

an explanation of evolution that incorporates many aspects of biology such as molecular genetics, phylogeny, natural selection, mutations, etc.

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Population

Back 24

a group of individuals of the same species

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Species

Back 25

a group of successfully interbreeding organisms that also produce fertile offspring

Front 26

Vestigial structure

Back 26

remnants of structures that were present and functional in the ancestral organisms

Front 27

Define the terms population, species, and evolution.

Back 27

A. Species: similar organisms capable of interbreeding and producing fertile offspring; genetically similar

B. Population: group of individuals of one species live in the same geographic area at the same time

C. Evolutionary time: time is relative; evidence with bacteria and some birds indicates modifications can occur in just a few generations

D. Evolution and natural selection: accumulation of heritable genetic changes over time; 2 populations may diverge to the point of becoming different species

Front 28

Name several historical figures and describe their contribution to views on classification and evolution.

Back 28

A. Aristotle: scale of nature; viewed organisms as moving toward more perfect state

B. da Vinci: recognized fossils of now extinct animals

C. Lamarck: traits acquired during parent's lifetime; realized natural phenomenon involved evolutionary change occurs

1. Acquired characteristics

2. Use vs disuse

3. First indication of theory of evolution

4. Natural selection

D. Hutton: gradualism- intermediate species

E. Cuvier: mass extinctions caused by catastrophes- new species arose, major change causing many animals to go extinct; punctuated equilibrium- abbreviated balance, no intermediates

F. Malthus: geometric vs. arithmetic growth; clergyman and economist; geometric (food depletes as animals eat it) vs. arithmetic (linear) growth; suggested inherited variations favorable to survival tend to be preserved; unfavorable traits are unlimited

Front 29

Compare and contrast the ideas of Darwin, Lamarck, and Wallace.

Back 29

I. Combined views of Darwin and Lamarck

- Lamarck: use results in extension offspring will have longer neck (stretched neck passed on to offspring)

-Darwin: longer neck reaches higher leaves; longer neck survives; genetic drift toward favorable trait of a longer neck

II. Views of Darwin and Wallace- Evolution occurs through natural selection.

Front 30

Name and explain Darwin's 4 premises of evolution by natural selection.

Back 30

1. Variation: individuals in a population exhibit variation in traits (some improve chances of survival and reproductive success)

2. Overproduction: each generation can produce more offspring than can survive

3. Limits on population growth: competition for limited resources- not all survive to reproduce

4. Differential reproductive success (survival of the fittest): individuals with most favorable combination of characteristics more likely to survive and reproduce (bad genes can also be passed on)

Front 31

Describe the modern synthesis and how it impacts views on evolution.

Back 31

Modern synthesis incorporates our expanding knowledge in genetics, systematics, paleontology, developmental biology, behavior, and ecology.

Front 32

Compare and contrast the various forms of evidence supporting evolution. (fossil record, homology, homoplasy, vestigial structures, and molecular and developmental homologies).

Back 32

I. Fossil record

A. Relationships/lineage/progression: connections between living and dead organisms; earliest unicellular organisms to organisms living today

B. Genetic relationships: DNA successfully recovered some changing historical relationships

C. Other fossil evidence: preserved footprints and embryos

D. Bias fossil record

1. Fossilization depend upon "rapid" preservation: favors organisms dying in aquatic/marine and those trapped in bags and tar pits over topical rainforest organisms rapidly decay

2. Fossilization influenced by body structure: organisms with hard body parts are more likely to form fossils than those with soft body parts

II. Comparative Anatomy

A. Homology, homoplasy, and analogy

B. Vestigial structures: remnants of past structures; no longer confer a selective advantage; happens over time as useful structure becomes smaller and/or loses function and/or degenerates

C. Examples

1. Human anatomy: fused tailbones, third molars wisdom teeth, and muscles that move ears

Front 33

Balanced polymorphism

Back 33

a type of genetic polymorphism in which 2 or more alleles persist in a population as a result of natural selection

Front 34

Bottleneck effect

Back 34

an event that rapidly, randomly, and dramatically decreases size of a population

Front 35

Cline

Back 35

gradual change in a specie's phenotype and genotype through a series of geographically separate populations of the same species

Front 36

Directional selection

Back 36

natural selection selects against one of the phenotypic extremes and favors the intermediates and other phenotypic extreme

Front 37

Disruptive selection

Back 37

natural selection selects against the intermediates and favors the phenotypic extremes

Front 38

Founder effect

Back 38

when a small group of individuals starts a new colony and the new population arises from that original group; as a result, the group exhibits little genetic variation

Front 39

Frequency dependent selection

Back 39

works to preserve balanced polymorphism; occurs when the frequency of a phenotype in a population determines the fitness of that trait

Front 40

Genetic drift

Back 40

a change in allele frequencies from one generation to the next

Front 41

Genetic polymorphism

Back 41

genetic variation among individuals of a population

Front 42

Geographic variation

Back 42

difference in genotype and phenotype frequencies in a population as a result of an environmental gradient (altitude)

Front 43

Heterozygote advantage

Back 43

works to preserve balanced polymorphism; occurs when the heterozygote has a higher level of fitness than either homozygote

Front 44

Inbreeding

Back 44

mating of genetically similar or genetically close individuals

Front 45

Stabilizing selection

Back 45

natural selection selects against phenotypic extremes and favors intermediate phenotypes

Front 46

Define, compare and contrast, and give examples of microevolution including nonrandom mating, mutation, genetic drift, and gene flow.

Back 46

I. Microevolution: generation to generation changes within a population; alleles or genotypes frequencies within a population are affected; result is moving away from genetic equilibrium (Hardy-Weinberg); gradual changes toward new species

II. Processes leading to microevolution

A. Nonrandom mating changes genotype frequencies

1. Mate selection involved by phenotype or result of populations/ cultural constraints

2. Assortive mating: selection by phenotype; change in phenotype at loci involved in mate choice

3. Inbreeding: caused by population/cultural constraints; when individuals are more closely related than if chosen randomly from general population; allele frequency not affected; frequency of homozygous genotypes increases

III. Mutations increases variation within population

A. Mutation: spontaneous, non-direct change in DNA sequence; produce genetic variation; overall fitness may be affected

IV. In genetic drift random events change allele frequency.

A. Genetic drift: random event decreases genetic variation; change in allele frequencies over time; decreases genetic variation within a population; increases genetic difference

among different populations

V. Genetic drift can occur following a bottleneck

A. Bottleneck effect: random, rapid, severe decrease in population size; caused by disease, exploitation, or sudden environmental change; genetic drift if population numbers decrease too far

VI. Genetic drift can occur as a result of the founder effect

A. Founder effect: few individuals of a larger population found a new colony; new population has only alleles of colonizers

VII. Gene flow generally increases variation within a population

A. Gene flow occurs when breeding individuals migrate between 2 populations 2; increase in genetic variability in recipient population

Front 47

Define, compare and contrast, and give examples of genetic polymorphism, balanced polymorphism, heterozygote advantage, frequency dependent selection, and geographic variation.

Back 47

I. Maintaining genetic variation in populations

A. Mutations

B. Sexual reproduction contributes to genetic variation: different parent alleles

C. Genetic polymorphism: genetic variability between members of a population (ABO blood groups)

D. Balanced polymorphism: genetic polymorphism where 2 or more alleles persist in a population; natural selection is involved; maintained by heterozygote advantage and frequency-dependent selection

Front 48

Adaptive radiation

Back 48

evolution of several species from one or a few ancestral species; occurs in relatively short time frame

Front 49

Allometric growth

Back 49

growth of different body parts at different rates

Front 50

Allopatric speciation

Back 50

formation of 2 new species following the physical separation of individuals of a single population

Front 51

Gradualism

Back 51

evolution occurs as a result of slow steady changes over time

Front 52

Hybrid inviability

Back 52

egg and sperm of 2 different species are genetically incapable of producing a viable zygote and embryo

Front 53

Hybrid sterility

Back 53

gametes of interspecies hybrid are not normal and able to produce a zygote

Front 54

Hybrid breakdown

Back 54

the hybrid is unable to reproduce successfully; F1 and F2 generations may be produced

Front 55

Hybrid zone

Back 55

an area of overlap between closely related species or subspecies in which interbreeding occurs

Front 56

Macroevolution

Back 56

large-scale changes over long time periods resulting in phenotypic changes that warrant placement of the organism into a new taxonomic group or above the species level

Front 57

Microevolution

Back 57

small-scale changes that occur within a species as a result of changes in the allele or genotype frequencies

Front 58

Paedomorphosis

Back 58

retention of juvenile features in the adult body form

Front 59

Preadaptation

Back 59

a characteristic that functioned in one way originally but later changed in a way that was adaptive to the structure having a different role

Front 60

Prezygotic barrier

Back 60

something that prevents fertilization from occurring (prevents formation of a zygote); prevents hybrid formation

Front 61

Postzygotic barrier

Back 61

something that occurs after fertilization (formation of a zygote) that prevents a hybrid from living long enough to form a new species

Front 62

Punctuated equilibrium

Back 62

evolution proceeds with period of little or no change and then rapid changes occur over a relatively brief period of time

Front 63

Sympatric speciation

Back 63

formation of 2 new species within the geographic region of the parent population; no physical barrier is present but reproductive isolating mechanisms are

Front 64

Define and describe the biological species concept of speciation and the associated problems.

Back 64

I. Species: reproductive isolation; fertile offspring are produced

II. Problems: includes only sexual reproduction

Front 65

Compare and contrast and give examples of prezygotic and postzygotic isolating mechanisms and barriers for reproductive isolation.

Back 65

I. Reproductive isolation in biological species

A. Dividing point: zygote formed by fusion of egg and sperm

II. Prezygotic barriers

A. Temporal isolation: species reproduce at different times of day, season, or year preventing cross fertilization

B. Habitat isolation: species in the same geographic area, but live and breed in different habitats that area (Frogs)

C. Behavioral isolation: many animals exchange a distinct series of signals before mating (visual, chemical, or oral) (albatross mating dance, blue burrow blue object, flashing frequencies of fireflies)

D. Mechanical isolation: structural differences in reproductive organs prevent mating (black and white sage)

E. Gametic isolation: molecular and chemical differences between species gametes prevents formation of a zygote; egg and sperm incompatible (surface of egg has specific proteins)

III. Postzygotic barriers

IV. Barriers to hybrid longevity

A. Hybrid inviability: embryo of intraspecific hybrid spontaneously aborts

B. Hybrid sterility: interspecific hybrid lives; cannot reproduce

C. Hyrbrid breakdown: hybrid lives and F1 hybrids mate to produce F2 hybrid generation; unable to continue generations because of some defect