Deck 10: Lifes Origins and Biodiversity

Question 1

It is thought by scientists that the earliest living organisms

A)originated on another planet.
B)were photosynthetic.
C)used carbon monoxide as a carbon source.
D)used aerobic respiration.
E)made use of sulfur and hydrogen gas as energy sources.

Answer 1

E

Question 2

The Cambrian Explosion provided a wealth of fossil remains for scientists to uncover. Many of the animals from this time period had tough skins or shells. This would

A)protect the animal from osmotic pressure.
B)be a disadvantage for these organisms and lead to their death and fossil formation.
C)protect the animal from predators.
D)make these animals more desirable to predators.
E)allow the animals to move into different environments easily.

Answer 2

C

Question 3

Oxygen built up in the atmosphere approximately 2 billion years ago and

A)occurred due to carbon dioxide being split by lightning strikes.
B)could not have occurred without the oxygen coming from outer space.
C)destroyed ozone forming more oxygen.
D)helped to form the ozone layer that is so important to life today.
E)occurred because aerobic organisms required the oxygen.

Answer 3

D

Question 4

Many biologists feel that the first self-replicating organic systems were

A)types of RNA.
B)forms of DNA.
C)based on proteins.
D)formed in space.
E)plants.

Question 5

Which of the following is not associated with mass extinctions?

A)After mass extinctions new species evolve to replace others.
B)Mass extinctions do not affect species randomly.
C)Species living in isolated areas are more susceptible to extinction.
D)Mass extinctions take place over a very long geologic period of time.
E)Although new species may evolve, it will take millions of years to replace the losses of a mass extinction.

Question 6

What term is used to indicate a characteristic that is shared and inherited from a common ancestor?

A)homologous trait
B)analogous trait
C)cladistic trait
D)ancestral trait
E)derived trait

Question 7

Eukaryotic cells are thought to have

A)appeared about 2.1 billion years ago.
B)first appeared as parts of multicellular organisms.
C)evolved before prokaryotic cells.
D)developed when mitochondria grew much larger in size that they had been previously.
E)first appeared with tough cell walls.

Question 8

According to the endosymbiont hypothesis, what cellular components originated from free-living bacterial cells?

A)mitochondria and nucleus
B)nuclei and ribosomes
C)chloroplasts and ribosomes
D)chloroplasts and mitochondria
E)endoplasmic reticulum and mitochondria

Question 9

Around 580 million years ago, the first simple animals are seen in the fossil record. These first fossilized animals

A)had a hard protective shell protecting their bodies.
B)were photosynthetic.
C)were predominantly trilobites.
D)were all land animals.
E)were probably not related to the modern jellyfish and worms they resembled.

Question 10

Atmospheric chemists think that Earth's first atmosphere

A)contained large amounts of molecular oxygen.
B)consisted of carbon in the form of carbon monoxide.
C)contained nitrogen in the form of ammonia and nitrogen gas.
D)contained no oxygen atoms.
E)was very similar to today's atmosphere.

Question 11

When taxonomists classify organisms using a phylogenetic approach, they are most concerned with

A)derived traits.
B)ancestral traits.
C)cladists.
D)outgroups.
E)ingroups.

Question 12

Scientists have determined that the silversword alliance is most closely related to the tarweed based on

A)phylogenetic similarities.
B)molecular comparisons.
C)the ability of the two plants to interbreed.
D)their geographical closeness.
E)seed shape and color.

Question 13

Stanley Miller conducted a famous experiment in the 1950s. This experiment

A)tried to determine how evolution occurs.
B)mimicked the early Earth's atmosphere as we know it today.
C)showed that simple organic molecules came from outer space.
D)used sunlight as an energy source.
E)showed that some organic molecules could be formed from non-organic starting materials.

Question 14

During which geological era did Pangea break apart?

A)Archean
B)Paleozoic
C)Mesozoic
D)Cenozoic
E)Proterozoic

Question 15

What level of biological classification is less inclusive than class?

A)domain
B)phylum
C)kingdom
D)order
E)division

Question 16

What type of organisms can generate organic molecules and obtain energy from inorganic molecules like iron, sulfur, and hydrogen?

A)chemoautotrophs
B)photoautotrophs
C)heterotrophs
D)homotrophs
E)organotrophs

Question 17

What term is used to indicate a relatively new characteristic, in an evolutionary sense?

A)homologous trait
B)analogous trait
C)cladistic trait
D)ancestral trait
E)derived trait

Question 18

Paleontologists have found fossils dating back 3.6 billion years. These closely resemble

A)nothing alive today.
B)blue-green algae present today.
C)small invertebrate animals.
D)today's simplest plants.
E)fungi.

Question 19

What is the proper way to write a species name?

A)Pantera
B)Pantera Leo
C)Pantera leo
D)pantera Leo
E)pantera leo

Question 20

Biologists think that the first photosynthetic cells

A)used water as an electron donor.
B)were the first living cells to develop.
C)lived more than 2.8 billion years ago.
D)released hydrogen into the atmosphere.
E)required oxygen rather than carbon dioxide.

Question 21

Evidence from geology suggests that initially the earth's atmosphere did not contain

A)O_2.
B)CO_2.
C)H₂S.
D)H₂O.
E)CH₄.

Question 22

Which of the following provided the selective pressures that most directly promoted the evolution of photosynthesis?

A)the drop in surface UV radiation caused by the formation of the ozone layer
B)the depletion of dissolved organic material from the oceans
C)the ability of some organisms to use oxygen to generate ATP during respiration
D)an increase in visible light intensity at the surface of the Earth, caused by solar flares
E)an increase in volcanic activity and release of CO₂ into the atmosphere

Question 23

What role might clays have played in the formation of macromolecules before the evolution of cells?

Question 24

When the photosynthetic organisms evolved the ability to split water, they produced _____ as a waste material, which was poisonous to most of the cells then alive.

A)hydrogen gas
B)hydrogen sulfide
C)water
D)carbon dioxide
E)oxygen

Question 25

Discuss the rationale behind taxonomists placing sharks and dolphins in different taxonomic groups, even though they are both aquatic, have very similar body forms, and share other traits as well.

Question 26

The oldest fossils look as though they were formed by organisms that resemble modern

A)sponges.
B)red algae.
C)jellyfish.
D)amebas.
E)prokaryotes.

Question 27

Since all organisms contain DNA (or RNA), how can DNA be used as a trait in studying phylogeny?

Question 28

Scientists believe that macromolecules could have been formed before there were living cells by

A)chemical processes removing water from components.
B)oxidation of compounds containing phosphate.
C)lightning discharge catalyzing addition of water to molecules.
D)enzyme-mediated condensation reactions.
E)acidic hydrolysis of compounds in the Earth's oceans.

Question 29

In many areas of the world, humans are destroying habitats at an alarming rate. Why is habitat destruction so dangerous?

Question 30

For many years, biologists felt that the highest level of classification of living organisms was the five kingdoms. Recently, some biologists have proposed that the hierarchical classification of organisms start with three domains, the Bacteria, the Archaea, and the Eucarya. Explain the reasoning behind this proposal and why the Bacteria and the Archaea should be in separate domains even though their members are all prokaryotes.

Question 31

Which of the following is not a kingdom in the Eucarya?

A)Archaea
B)Plantae
C)Fungi
D)Protista
E)Animalia

Question 32

Of the following, which kingdom contains the most diversity in terms of DNA sequences?

A)Plantae
B)Protista
C)Fungi
D)Animalia
E)All of these are approximately equivalently diverse.

Question 33

Most of the mass of the solar system is made up of the elements

A)carbon and hydrogen.
B)oxygen and hydrogen.
C)helium and hydrogen.
D)nitrogen and hydrogen.
E)nitrogen and carbon.

Question 34

Consider the evolution of metabolic pathways. We believe that these pathways evolved from the

A)precursor to the end product, as enzymes became more efficient over time.
B)precursor to the end product, as cells simplified the biochemistry of the external environment.
C)end product to the precursor, as cells gradually evolved according to a predetermined plan.
D)end product to the precursor, as intermediates in the pathway were depleted in the environment.
E)end product to the precursor, as photosynthesis began to supply the energy to power the changes at each stage.

Question 35

Match the following examples with the correct descriptive term.
6. ___ Possible origin of chloroplasts and mitochondria
7. ___ Can obtain nourishment from external sources
8. ___ Can use carbon dioxide to produce organic molecules
9. __ Can generate organic molecules using inorganic molecules like hydrogen sulfide and iron
10. ___ Able to use oxygen as a final electron acceptor
A. endosymbiont
B. heterotrophs
C. chemoautotrophs
D. autotrophs
E. aerobic

Question 36

Evidence from Stanley Miller's experiments and evidence from carbonaceous chondrites collected from meteorites, taken together, most directly support the contention that

A)life can arise under conditions of extreme heat or cold.
B)organic molecules can be synthesized by natural chemical processes.
C)life did not arise on earth, but rather arrived from another planet by meteorite.
D)living organisms are required to produce complex organic compounds.
E)organic compounds require gravity for their formation.

Question 37

The endosymbiont hypothesis suggests that the mitochondria of eukaryotic cells are descended from captured

A)cyanobacteria.
B)archaebacteria.
C)aerobic bacteria.
D)chemoautotrophic bacteria.
E)eukaryotic algae.

Question 38

Explain how the presence of Pangea relates to the fact that most marsupials are found in Australia.

Question 39

Consider the 4.6-billion-year history of the Earth. Geological and fossil evidence indicates that during the greatest fraction of its history, the Earth

A)was too hot to have either a solid surface or any form of life.
B)had organic molecules in liquid water, but no living forms.
C)had unicellular organisms, but not multicellular.
D)had both multicellular and unicellular organisms, but no terrestrial (land) forms.
E)had both terrestrial, freshwater, and marine organisms, both unicellular and multicellular.

Question 40

Why are most Hawaiian silverswords found at high altitudes?

Question 43

How do we know that the atmosphere of the earth experienced an increase in O₂ and became oxidizing between 2.5 and 2 billion years ago?

Question 45

Roughly a quarter of all known species are currently threatened with extinction. What is the primary source of this threat?

Question 46

Compare the first forms of photosynthesis to evolve with the form used by green plants today.

Question 47

Contrast homologous and analogous traits, giving examples.

Question 48

Scientists think that the first eukaryotic cells did not have a cell wall. Indicate a disadvantage to this, and tell how cells might have compensated for it. Give an advantage to this, and tell how cells might have exploited it.

Question 49

Many scientists feel that we are headed toward another mass extinction because of man's actions and our effect on the ecosystem Earth. What have we learned from previous mass extinctions that may provide an idea of the consequences of such a mass extinction? What should man do to try to prevent such an occurrence?