pages 444-453

Question 1

theory of evolution by natural selection

Answer 1

formulated independently by Charles Darwin and Alfred Russel Wallace; explains how organisms have come to be adapted to environments.

Question 2

special creation

Answer 2

leading explanation for the diversity of organisms prior to Darwin. Beliefs were explained by the instantaneous and independent creation of living organisms by a supernatural being.

Question 3

3 assumptions of special creation

Answer 3

1) All species are independent, in the sense of being unrelated to each other
2) Life on Earth is young – perhaps just 6000 years old
3) Species are immutable, or incapable of change

Question 4

Scientific theories usually have two components:

Answer 4

a pattern and a process.

Question 5

pattern component

Answer 5

a statement that summarizes a series of observations about the natural world. About facts – about how things are in nature.

Question 6

process component

Answer 6

mechanism that produces that pattern or set of observations.

Question 7

plato

Answer 7

claimed that every organism was an example of a perfect essence, or type, created by God, and that these types were unchanging. Acknowledged that the individual organisms present on Earth might deviate slightly from the perfect type. Key to understanding life was to ignore the shadows and focus on understanding each type of unchanging, perfect essence.

Question 8

typological thinking

Answer 8

based on the idea that species are unchanging types and variations within species are unimportant or even misleading.

Question 9

aristotle

Answer 9

organized organisms into a linear scheme called the great chain of being, or the scale of nature. Proposed that species were organized into a sequence based on increased size and complexity, with humans at the top. Characteristics of species were fixed.

Question 10

assumptions made by aristotle

Answer 10

1) Species are fixed types

2) Some species are higher – in the sense of being more complex or “better” – than others

Question 11

evolution

Answer 11

proposed by Lamarck; species are not static but change through time.

Question 12

Lamarckian evolution

Answer 12

claimed that simple organisms originate at the base of the chain by spontaneous generation and then evolve by moving up the chain over time. Progressive in the sense of always producing larger and more complex species. Also contended that species change via the inheritance of acquired characteristics – an individual develops in response to its environment and its phenotype changes and passes these to offspring (long necks on giraffes).

Question 13

Darwin and Wallace

Answer 13

emphasized that evolution occurs because individuals with certain traits leave more offspring than others.

Question 14

population

Answer 14

consists of individuals of the same species that are living in the same area at the same time.

Question 15

population thinking

Answer 15

claim by Darwin; instead of being unimportant or an illusion, variation among individuals in a population was the key to understanding the nature of the species.

Question 16

Theory of evolution was revolutionary:

Answer 16

1) Overturned the idea that species are static and unchanging
2) Replaced typological thinking with population thinking
3) It was scientific. Proposed a mechanism that could account for change through time and made predictions that could be tested through observation and experimentation.

Question 17

descent with modification

Answer 17

Darwin; species that lived in the past are the ancestors of the species existing today, and that species change through time.

Question 18

The pattern component of the theory of evolution by natural selection makes two predictions about the nature of species:

Answer 18

1) Species change through time

2) Species are related by common ancestry

Question 19

fossil

Answer 19

any trace of an organism that lived in the past.

Question 20

fossil record

Answer 20

consists of all the fossils that have been found on Earth and described in scientific literature. Fossil record suggests over 99% of all the species that have ever lived are now extinct.

Question 21

extant species

Answer 21

those living today

Question 22

sedimentary rocks

Answer 22

form from sand or mud or other materials deposited at locations such as beaches or river mouths. Relative ages.

Question 23

geologic time scale

Answer 23

a sequence of named intervals called eons, eras, and periods that represented the major events in Earth history. Indicates that the Earth is much older than 6000 years as proposed by proponents of special creation.

Question 24

radioactive decay

Answer 24

steady rate at which unstable or parent atoms are converted into more stable daughter atoms. Can assign absolute ages.

Question 25

radiometric dating

Answer 25

reveals that Earth is about 4.6 billion years old and the earliest signs of life appear in rocks formed 3.4-3.8 billion years ago. Based on:

1) Observed decay rates of parent to daughter atoms
2) The ratio of parent to daughter atoms present in newly formed rocks
3) The ratio of parent to daughter atoms present in a particular rock sample

Question 26

Cuvier

Answer 26

published a detailed analysis of an extinct species called the Irish “elk.”

Question 27

law of succession

Answer 27

extinct species in the fossil record were succeeded by similar species.

Question 28

transitional feature

Answer 28

trait in a fossil species that is intermediate between those of ancestral and derived species.

Question 29

vestigial trait

Answer 29

a reduced or incompletely developed structure that has no function, or reduced function, but is clearly similar to functioning organs or structures in closely related species.

Question 30

phylogenetic tree

Answer 30

a branching diagram that describes the ancestor-descendant relationships among species or other taxa.

Question 31

homology

Answer 31

similarity that exists in species because they inherited the trait from a common ancestor. All three interact.

Question 32

genetic homology

Answer 32

occurs in DNA nucleotide sequences, RNA nucleotide sequences, or amino acid sequences.

Question 33

developmental homology

Answer 33

recognized in embryos.

Question 34

structural homology

Answer 34

similarity in adult morphology, or form.

Question 35

Chemicals that cause cancer in humans

Answer 35

can often be identified by testing their effects on mutation rates in bacteria, yeast, mice, etc. because the molecular machinery responsible for copying and repairing DNA is homologous in all organisms.

Question 36

Drugs intended for human use can be tested on mice or rabbits

Answer 36

if the molecules targeted by the drugs are homologous.

Question 37

Unknown sequences in human, rice, or other genomes

Answer 37

can be identified if they are homologous to known sequences in yeast, fruit flies, or other well studied model organisms.

Question 38

Speciation

Answer 38

process that results in one species splitting into two or more descendant species.

Question 39

Internal consistency

Answer 39

most powerful evidence for any scientific theory; observation that data from independent sources agree in supporting predictions made by a theory.