Biology 100 Unit 15

Question 1

Earth is considered _________________

Answer 1

4.6 billion years old

Question 2

3 things about Prokaryotes

Answer 2

–evolved by 3.5 million years ago
– Began oxygen production about 2.7 billion
years ago
– Lived alone for almost 2 billion years

Question 3

Single-celled ________________________ are considered to have evolved about 2.1 billion years ago.

Answer 3

eukaryotes

Question 4

_____________________ are considered to have evolved approximately 1.2 billion years ago.

Answer 4

Multicellular eukaryotes

Question 5

is stored geological layers

Answer 5

Biological history

Question 6

2.5 billion year-old fossilized prokaryote mats suggest that photosynthetic bacteria produced

Answer 6

O2 , which created an aerobic atmosphere important for life.

Question 7

These fossilized mats containing photosynthetic bacteria are called _________________.

Answer 7

stromatalites

Question 8

This is referred to as the __________ _____________.

Answer 8

oxogen revolution

Question 9

Earth’s early atmosphere probably contained

Answer 9

H2O, CO, CO2, N2, and possibly some CH4.

Question 10

Theabsenceof oxidation in the oldest rocks shows that there little or no ____________was present.

Answer 10

O2

Question 11

In the ancient world

Answer 11

Volcanic activity, lightning, and UV radiation were likely prevalent

Question 12

All organisms today arise via ______________ stating that life comes from life, however how did the 1st living organisms get here?

Answer 12

biogenesis,

Question 13

This discrepancy is known as the ______________, still no complete answer to this dilemma

Answer 13

biogenesis

Question 14

According to current hypotheses, the first organisms arose via chemical evolution in 3 stages.

Answer 14

– 1. Collection of monomers
– 2. Formation of RNA polymers (simple genes)
– 3. Assembly of complementary RNA (replication)

Question 15

were likely synthesized from simpler molecules…this takes energy

Answer 15

Macromolecules

Question 16

On the early Earth, it is proposed that inorganic chemicals were energized by

Answer 16

lightning or UV radiation and combined to form new structures.

Question 17

In 1953, ______________ simulated what he thought was the “early earth” in his laboratory.

Answer 17

stanly miller

Question 18

Simple organic molecules can polymerize on hot rocks or clay.esent on the early earth.

Answer 18

– This can produce polypeptides and short nucleic acids. – Short RNA pieces may have been acted as the 1st type
of nucleic acid pr

Question 19

in various situations does occur, however they are also often broken down into monomers during these same processes.

Answer 19

Polymerization of organic monomers

Question 20

If a RNA polymer formed, the catalytic ability of RNA may have lead to ________________________.

Answer 20

self replication of RNA

Question 21

• Collection of monomers
• Formation of short RNA polymers: simple “genes”
• Assembly of a complementary RNA chain, the first step in the replication of the original “gene”

Answer 21

Spontaneous RNA assembly

Question 22

can act as rough templates for the formation of short polypeptides.

Answer 22

short RNA molecules

Question 23

Such assemblies may act as primitive molecular co- operation

Answer 23

Co-ops

Question 24

can then assist with RNA replication.

Answer 24

polypeptides

Question 25

_______________are RNA molecules that act like enzymes

Answer 25

Ribosomes

Question 26

if they are placed into an aqueous (water-based) solution, they form a self-sealing sphere

Answer 26

Because phospholipids have hydrophobic tail and hydrophillic heads

Question 27

These membrane enveloped protecting nucleic acids an proteins had a

Answer 27

selective advantage

Question 28

A protected chemical environment may have given rise to a primitive metabolism.

Answer 28

—Natural selection then favors those co-ops that are most efficient, and effectively reproduce (or divide).
– Under continued selective pressure, these may have evolved into the first simple prokaryotic cells.

Question 29

All of these steps would have to have occurred ________________ in nature.

Answer 29

in sequence

Question 30

Although scientists have not made life, they attest that over the course of billions of years, the correct combinations of macromolecules came together to form an a simple cell, _________________________ ___________________________________________

Answer 30

then enviromental pressures are responsible the variety we see today

Question 31

are used to categorize organisms into time frames when they evolved and existed on earth

Answer 31

Distinct Geological eras

Question 32

Radiometric dating uses _______________________ which decay with a predictable half-life. The 1⁄2 life is measured, and compared to current standards to determine the age of ancient fossils and geologic rocks.

Answer 32

radioactive isotopes

Question 33

according to the theory of __________________________:
the Earth’s crust is divided into giant, irregularly
shaped plates that
essentially float on the underlying mantle.

Answer 33

plate tectonics

Question 34

In a process called _______________________ that movements in the mantle cause the plates to move.

Answer 34

continental drift

Question 35

Since the origin of multicellular life roughly 1.5 billion years ago, there have been three occasions in which the landmasses of Earth came together to form a supercontinent called

Answer 35

pangea

Question 36

Fossils of lungfishes are found on every continent

except Antarctica.

Answer 36

Continental drift explains the distribution of lungfishes.

Question 37

Today, living lungfishes are found in

Answer 37

South America, – Africa, and

– Australia.

Question 38

When did lung fish evolve

Answer 38

when pangea was extinct

Question 39

result from the movements of crustal plates.

Answer 39

volcanoes and earthquakes

Question 40

The boundaries of plates are hotspots of

Answer 40

volcanoes and earthquakes

Question 41

The fossil record shows that the vast majority of

species that have ever lived are now extinct.

Answer 41

Extinction is inevitable in a changing world.

Question 42

Over the last 500 million years,

Answer 42

– five mass extinctions have occurred, and
– in each event, more than 50% of the Earth’s
species went extinct.
– The boundaries of plates are hotspots of volcanic and earthquake activity.

Question 43

– occurred about 251 million years ago,
– defines the boundary between the Paleozoic and Mesozoic eras,
-claimed 96% of animal species
– took a tremendous toll on terrestrial life, and
– was likely caused by enormous volcanic eruptions.

Answer 43

The Permian mass extinction

Question 44

caused the extinction of all the dinosaurs except birds

and

Answer 44

The Cretaceous mass extinction

Question 45

The Cretaceous mass extinction

Answer 45

was likely caused by a large asteroid that struck the Earth, blocking light and disrupting the global climate.

Question 46

are periods of evolutionary change that

Answer 46

adaptive radiations

Question 47

adaptive radiations cause

Answer 47

– occur when many new species evolve from a common
ancestor that colonizes a new, unexploited area and
– often follow extinction events.

Question 48

Radiations may result from the evolution of new adaptations such as

Answer 48

– wings in pterosaurs, birds, bats, and insects and

– adaptations for life on land in plants, insects, and tetrapods.

Question 49

The fossil record can tell us

Answer 49

– what the great events in the history of life have been
and
– when they occurred.

Question 50

provide a big-picture view of how those changes came about.

Answer 50

Continental drift, mass extinctions, and adaptive radiation

Question 51

We are now increasingly able to understand the basic biological mechanisms that underlie the changes seen

Answer 51

the fossil record

Question 52

– addresses the interface of evolutionary biology and
developmental biology and
– examines how slight genetic changes can produce major morphological differences.

Answer 52

the field of evo-devo

Question 53

Genes that program development control the

Answer 53

• rate
• timing
• spatial pattern of change in an organism’s form as it developes

Question 54

Many dramatic evolutionary transformations are the result of a change

Answer 54

in the rate or timing of developmental events.

Question 55

is the retention in the adult of body structures that were

juvenile features in an ancestral species and

Answer 55

paedomormphesis

Question 56

paedomormphesis occurs in the

Answer 56

salamander in which sexually mature adults retain gills and other larval features.

Question 57

Slight changes in the relative growth of different body parts can change

Answer 57

an adult form substantially.

Question 58

Skulls of humans and chimpanzees are

Answer 58

–more similar as fetuses but

– quite different as adults due to different rates of growth.

Question 59

– are called master control genes and

– determine basic features, such as where pairs of wings or legs develop on a fruit fly.

Answer 59

homeotic genes

Question 60

Profound alterations in body form can result from

Answer 60

– changes in homeotic genes or

– how or where homeotic genes are expressed.

Question 61

Duplications of homeotic gene clusters may explain the evolution of

Answer 61

vertebrates from invertebrates.

Question 62

we see today, may have evolved by increments from simpler versions of the same basic genes.

Answer 62

complex structures

Question 63

In the evolution of an eye or any other complex structure, behavior, or biochemical pathway, each step must

Answer 63

– bring a selective advantage to the organism possessing it and
– increase the organism’s fitness.

Question 64

In other cases, evolutionary novelties result from the

Answer 64

gradual adaptation of existing structures to new functions.

Question 65

Such structures that evolve in one context but become co-opted for another function are often called ____________________.

Answer 65

exaptations

Question 66

Examples of exaptations include

Answer 66

– feathers that may have first functioned for insulation
and later were co-opted for flight and
– flippers of penguins that first functioned for flight and were co-opted for underwater swimming.

Question 67

Phylogeny is the

Answer 67

evolutionary history of a species or group of species

Question 68

Phylogeny can be inferred from

Answer 68

– the fossil record,

– morphological homologies, and – molecular homologies.

Question 69

is a discipline of biology that focuses on

Answer 69

Systematics

Question 70

Two examples of systematics

Answer 70

• Classifying organisms

- Determining their evolutionary relationship

Question 71

Carolus Linnaeus introduced _________________________ a system of naming and classifying species.

Answer 71

taxonomy,

Question 72

Biologists assign each species a two-part scientific name, or binomial, consisting of

Answer 72

– a genus and

– a unique part for each species within the genus.

Question 73

_____________are grouped into progressively larger

categories.

Answer 73

genera;

Question 74

Each taxonomic unit is called a

Answer 74

taxon

Question 75

the order of taxonomies

Answer 75

domain 
kingdom 
Phylum 
class
order
family 
genus 
species

Question 76

Biologists traditionally use ____________________ to depict hypotheses about the evolutionary history of species.

Answer 76

phylogenetic trees

Question 77

reflect the hierarchical classification of groups nested within more inclusive groups.

Answer 77

branching diagrams

Question 78

Phylogenetic trees indicate the probable

Answer 78

evolutionary relationships among groups and patterns of descent.