Chapter 15

Question 1

Earth’s environments are in a state of ___ – ever changing, but balanced and resilient – so conditions don’t swing too wildly, and the planet continues to be habitable

Answer 1

Dynamic Equilibrium

Question 2

The envelope of gas that surrounded early Earth

Answer 2

Primary Atmosphere

Question 3

Earth generated a ___ by volcanic outgassing of volatile materials from its interior

Answer 3

Secondary Atmosphere

Question 4

Traces of oxygen were probably generated in the early atmosphere through the breakdown of water molecules into oxygen and hydrogen by ultraviolet light

Answer 4

Photodissociation

Question 5

A chemical reaction whereby plants use light energy to induce carbon dioxide to react with water, producing carbohydrates and oxygen

Answer 5

Photosynthesis

Question 6

The period from 2.4 to 2.0 billion years ago, during which free oxygen began to build up in the ocean and atmosphere, is known as the ___

Answer 6

Great Oxygenation Event

Question 7

Photosynthesis in the oxygen cycle is balanced by ___, in which organic carbon combines with oxygen to form carbon dioxide

Answer 7

Decomposition

Question 8

Around 3.55 billion years ago, entire colonies of bacterial life forms have developed and can be found in fossils of layered structures of bacterial origin

Answer 8

Stromatolites

Question 9

Extracting energy and material sustenance from its environment

Answer 9

Metabolism

Question 10

Set of 20 carbon-based molecules

Answer 10

Amino Acids

Question 11

The basic structure and functional unit of life; a complex grouping of chemical compounds enclosed in a porous membrane

Answer 11

Cell

Question 12

Maintaining a relatively constant chemical environment

Answer 12

Homeostasis

Question 13

Carbon is essential to life on Earth because carbon atoms can ___ to form very long chains and complex molecules which enable cells to function

Answer 13

Polymerize

Question 14

Every cell nucleus contains a molecule called ___

Answer 14

DNA (Deoxyribonucleic Acid)

Question 15

A double-chain biopolymer that contains all the genetic information needed for an organism to grow and reproduce

Answer 15

DNA

Question 16

DNA is like a good ole’ twisted ladder, in each run consists of two complementary organic molecules called ___, which fit together like a lock and key

Answer 16

Nucleotides

Question 17

Most experts believe that a simpler, single-stranded molecule called ___ must have appeared first

Answer 17

RNA (Ribonucleic Acid)

Question 18

___ is when animals obtain energy from the food they eat, and oxygen is needed to release the energy

Answer 18

Aerobic Metabolism

Question 19

Many kinds of bacteria have ___, obtaining energy through the nonoxygenated breakdown of food by the process of fermentation

Answer 19

Anaerobic Metabolisms

Question 20

___ is when an organism can extract energy directly from hydrogen, sulfur or salt

Answer 20

Chemosynthesis

Question 21

Organisms that live in the extreme end of the chemical and thermal circumstances in which organic molecules can remain chemically stable are called ___

Answer 21

Extremophiles

Question 22

Chemical residues that signal the former presence of life

Answer 22

Biosignatures

Question 23

A single-celled organism with no distinct nucleus - that is, no membrane separates its DNA from the rest of the cell

Answer 23

Prokaryote

Question 24

The broadest taxonomic category of living organisms; biologists today recognize three domains: Bacteria, Archaea, and Eukarya

Answer 24

Domain

Question 25

___ are mound-like structures that consist of many thin layers of calcium carbonate

Answer 25

Stromatolites

Question 26

Similar structures to stromatolites can be found today and are formed in seawater by the action of photosynthetic organisms called ___

Answer 26

Cyanobacteria

Question 27

An organism composed of cells - that is, cells that have a well-defined nucleus and organelles

Answer 27

Eukaryote

Question 28

Eukaryotes appeared at least ___ billion years ago

Answer 28

1.4

Question 29

The earliest fossils of multicellular eukaryotic organisms appeared at the end of the Proterozoic Era, preserved in rock about ___ million years old. These organisms were called ___

Answer 29

630, Ediacara Fauna

Question 30

The theory that life on Earth has developed gradually, from simple organism to more complex organisms

Answer 30

Evolution

Question 31

The process by which individuals that are well adapted to their environment have a survival advantage and pass on their favorable characteristics to their offspring

Answer 31

Natural Selection

Question 32

A ___ trait is one that is transmissible from parent to offspring

Answer 32

Heritable

Question 33

Heritable traits are encoded in ___ on an organisms DNA

Answer 33

Genes

Question 34

A population of genetically and/or morphologically similar individuals that can interbreed and produce fertile offspring

Answer 34

Species

Question 35

Darwin favored extremely slow, ___ change

Answer 35

Gradual Called Gradualism

Question 36

Stephen Jay Gould, and some other folks, argued for ___, in which species persist for a very long time with few changes and undergo occasional periods of very rapid change

Answer 36

Punctuated Equilibrium

Question 37

Remains of an organism from a past age, embedded and preserved in rock

Answer 37

Fossil

Question 38

___ is when bones and shells are often replaced, molecule by molecule, by minerals carried in solution by groundwater

Answer 38

Mineralization

Question 39

Mineralization creates ___

Answer 39

Wood

Question 40

___ can preserve even delicate leaf structures; it occurs when volatile material in the plant evaporates, leaving behind a thin film of carbon

Answer 40

Carbonization

Question 41

Organelles that are responsible for producing colour

Answer 41

Melanosomes

Question 42

Fossilized evidence of an organism's life processes, such as tracks, footprints, and burrows

Answer 42

Trace Fossil

Question 43

Prehistoric animals also left behind fecal droppings (shit.) called ___ when preserved and fossilized

Answer 43

Coprolites

Question 44

The Paleozoic Era started ___ million years ago, with the Cambrian period

Answer 44

541

Question 45

The Cambrian period ushered in the development of ___

Answer 45

Skeletons, internal and external

Question 46

Hard shell organisms are called ___

Answer 46

Trilobites

Question 47

The second-broadest taxonomic category. The six recognized kingdoms are Bacteria, Archaea, and Protista, Plantae, Fungi, and Animalia. The hierarchical subdivisions of this are phylum, class, order, family, genus, and species

Answer 47

Kingdom

Question 48

Plants evolved from green algae more than ___ million years ago

Answer 48

600

Question 49

During the Silurian period, ___ evolved. These plants have structural support from stems and limbs, and they have a set of vessels through which water and dissolved elements are transferred from the roots to the leaves

Answer 49

Vascular Plants

Question 50

Gas exchange occurs by diffusion through adjustable openings in the leaves called ___

Answer 50

Stomata

Question 51

A naked-seed plant

Answer 51

Gymnosperm

Question 52

First creature to make transition from sea to land. Crabs, spiders, centipedes, and insects. Named for their jointed legs.

Answer 52

Arthropods

Question 53

The phylum that humans belong to. These animals have the least primitive version of a spinal cord.

Answer 53

Chordates

Question 54

Permanent disappearance of a species

Answer 54

Extinction

Question 55

__% of all living species disappeared at the end of the Permian period, in the greatest mass extinction in history

Answer 55

96

Question 56

A flowering, or seed-enclosed, plant

Answer 56

Angiosperm

Question 57

During the Pleistocene epoch, giant sloths, tapirs, saber-toothed cats, dire wolves, bison, mammoths, and mastodons roamed through Europe, North America, and South America, constituting what is know as the ___

Answer 57

Pleistocene Megafauna

Question 58

Human-like organisms

Answer 58

Hominids

Question 59

Routinely walking upright

Answer 59

Bipedal

Question 60

Scientists refer to the fact that the majority of species that have ever lived are now extinct as ___

Answer 60

Background Extinction

Question 61

A catastrophic episode in which a large fraction of living species become extinct within a geologically short time

Answer 61

Mass Extinction

Question 62

The most famous mass extinction occurred __ million years ago and is sometimes called the __ extinction

Answer 62

65 and K-T