Evolution - Chapter 7

Question 1

Evolution

Answer 1

process that results in biological diversity
slow, continual, unpredictable change
tied to environmental conditions
inexact duplication of genetic information is inevitable

Question 2

Cause of evolution

Answer 2

genetic mutations provides a means of variation within a species
mutations can be neutral, harmful, or beneficial to a species
advantageous mutations provide a species with an improved ability to survive and reproduce, resulting in a population with a greater tendency towards that mutation

Question 3

Artificial selection

Answer 3

human influenced reproduction of organisms
the useful species population was increased, and individuals with desirable traits were used to produce subsequent generations

Question 4

Result of artificial selection

Answer 4

reduced genetic variability
potentially losing valuable genes
increases susceptibility of a species to disease, predators, or detrimental traits

Question 5

Georges-Louis Leclerc de Buffon

Answer 5

noted organisms that had features that were not useful

theorized that they were previously perfect creations that had changed

Question 6

Jean-Baptiste Lamarck

Answer 6

although the mechanism he proposed was in error, he is credited for proposing other ideas
evolution is the best explanation for both the fossil record and the extent of diversity of life
earth is ancient
adaptation to the environment is a primary product of evolution

Question 7

Lamarck’s theory

Answer 7

proposed a mechanism for evolution that included 2 principles
use and disuse = body organs used extensively to cope with the environment became stronger and larger while those that were not used deteriorate
inheritance of acquired characteristics = modifications an organism acquired during its lifetime could be passed along to its offspring

Question 8

Georges Cuvier

Answer 8

noted that fossils tend to occur in layers, with more complex life nearer the surface
many species do not exist in rock layers above or below them
theory of catastrophism = mass extinctions of species occurred on the planet at intervals, and new, perfect organisms were created to replace them

Question 9

Charles Lyell

Answer 9

theory of uniformitarianism = geological processes are slow and uniform and have operated from the origin of the Earth to the present
revolutionary, challenged the current beliefs that Earth was very young

Question 10

James Hutton

Answer 10

theory of gradualism = geological changes are slow and gradual, and take long periods of time
same idea as Lyell, however he did not lead to the conclusion that the Earth is ancient

Question 11

Reverend Thomas Malthus

Answer 11

wrote essay on social theory that Darwin read

organisms produce more offspring than can be supported, therefore there must be competition among them

Question 12

Alfred Russel Wallace

Answer 12

young naturalist working in Malaysia

helped Darwin with his discoveries while in the Galapagos Islands

Question 13

Fossils

Answer 13

traces of organic remains that have been preserved from decay in mineral deposits
initially, fossils were thought to be organisms that lived only thousands of years ago
however, many are very unusual and no fossils of current species are found, some are very deep, and they are often found in unexpected locations

Question 14

Biogeography

Answer 14

geographical distribution of species
islands have endemic species which are closely related to species on the nearest mainland or neighbouring islands
lands that have similar climates have unrelated animals, indicating that differences in environment are not creating the diversity directly

Question 15

Comparative embryology and anatomy

Answer 15

closely related organisms go through similar stages of embryonic development
anatomical similarities among species grouped in the same taxonomic category are reflections of their common descent

Question 16

Homologous features

Answer 16

develop from similar embryological origins
all constructed on the same pattern and include same parts
they therefore share a common ancestor
structures have been modified as they take on new functions

Question 17

Analogous features

Answer 17

perform the same function as one another, but they are not anatomically similar
indicative of a much more distant relationship and different embryological lines

Question 18

Vestigial features

Answer 18

structures that serve little to no purpose in an organism, but that are fully functioning in a closely related organism
recall Buffon’s theory

Question 19

Molecular biology

Answer 19

an organism’s hereditary background is reflected in its genes and their protein structure
two species considered to be closely related by other criteria should have a greater proportion of their DNA and proteins in common than more distantly related species
even taxonomically distant organisms have some proteins in common

Question 20

Charles Darwin

Answer 20

naturalist who spent many season aboard HMS Beagle
perceived the origin of new species and adaptations as closely related processes
two populations of a species could be isolated in different environments and diverge as each adapted
over many generations, the two populations could become dissimilar enough to be designated separated species

Question 21

Galapagos Island observations

Answer 21

only plants, birds, insects and reptiles were able to reach remote islands by crossing large expanses of open ocean
many unique species found nowhere else on Earth
unique species are descendants of ancestral species from the nearest continental land masses and will exhibit some similarities

Question 22

Natural selection

Answer 22

the way in which nature favours the reproductive success of some individuals, leading to evolution over countless generations
factors that contributed to this theory = 
exponential population increase
perceived stability of populations
limited resources and space
struggle for existence
uniqueness of individuals
individual variation is inherited

Question 23

Survival of the fittest

Answer 23

an individual’s ability to survive in its environment to reproductive maturity in order to achieve the passing of its genes
this passing of genes results in the adaptation of specied that make them well-suited to their environment

Question 24

Modern synthesis

Answer 24

paleontologists use radioisotopes which undergo radioactive decay to date rock formations that contain fossils, proving the age of the Earth

Question 25

Modern theory of evolution

Answer 25

evolution is defined as changes in the gene pool of a species over time
the gene pool consists of all alleles of all the individuals present in a population or particular species
natural selection acts to favour some genetic combinations over others

Question 26

Mutations

Answer 26

new alleles and genes produced by mutation can give rise to new traits when acted on by selection
homologous genes = closely related species inherit homologous genes which come from a common ancestor
pseudogenes = genes that have mutated so they are no longer useful, they still exist because they were not selected for or against

Question 27

Modern palaeontology

Answer 27

advances in the understanding of plate tectonics and continental drift have enhanced our understanding of why fossil locations were found in specific areas