This document provides an overview of evolution and related concepts. It begins by outlining the key objectives to be covered, which include understanding natural selection, mutation and gene recombination in evolution, the role of natural selection, types of isolation and speciation. It then defines evolution and discusses early theories of evolution. Key concepts like variation, natural selection, isolation and speciation are explained. Evidence for evolution such as paleontology, biogeography, anatomy and molecular biology is summarized. It concludes with classifications of living things and the general process of biological evolution.

1. Chapter 21 Evolution
Ong Yee Sing
2019

2. Objectives
1. To understand the main content of natural selection which was proposed by
Charles Darwin.
2. To understand mutation and gene recombination provide raw materials for
evolution of organisms.
3. To understand the role that played by natural selection in the evolution of
organisms.
4. To understand the concept and types of isolation and the relationship between
isolation and formation of species.
5. To understand the evidence and process of evolution
6. To understand the rough process of evolution from original lifer to the
appearance of eukaryotes.
7. To understand five Kingdom classification of organisms and its main content.
8. To understand the origin of human being.

3. Evolution演化
• the change in the characteristics of
a species over a long time

4. Theory of evolution
Theory of use and disuse
用进废退说
Theory of natural selection
自然选择说
Explain the evolution of life
from different perspectives

5. Law of use and disuse用进废退说
• By French biologist Jean-Baptiste
Lamarck (1744–1829),
In every animal which has not passed the
limit of its development, a more frequent
and continuous use of any organ gradually
strengthens, develops and enlarges that
organ, and gives it a power proportional
to the length of time it has been so used;
while the permanent disuse of any organ
imperceptibly weakens and deteriorates it,
and progressively diminishes its functional
capacity, until it finally disappears.

6. Experiments on the inheritance of mutilations
• August Weismann conducted
the experiment of removing the
tails of 68 white mice
repeatedly over 5 generations
• Reporting that no mice were
born in consequence without a
tail or even with a shorter tail.

7. Theory of natural selection自然选择说
• Darwin believes that evolution is the result of
long-term selection of organisms by the natural
environments as these organisms adapt to the
environment.
• Individuals who are able to adapt to the
environment are more likely to survive and
produce offspring. Therefore, the proportion of
offspring with favorable characteristics will
gradually increase with time, resulting in a
significant change in the external morphology or
internal structure of the species.
• The original population may have variation in
characteristics, and these differences become
unique features through environmental selection.

8. Theory of natural selection
Process Important concept
１
Individual
variation
Same species but variable in the structures and
functions among individuals of a population
２
Over
population
When the environmental resources are sufficient, the
number of individuals grows over the carrying capacity.
３ Competition
Insufficient resources leads to competition for survival.
４
Survival of
the fittest
Individuals who are more able to obtain living
resources or adapt to environmental changes
have greater chances of survival, and the
proportion of their offspring in the entire
environment will gradually increase.

9. • Any difference between cells, individual organisms, or groups of
organisms of any species caused either by genetic differences
(genotypic variation) or by the effect of environmental factors on the
expression of the genetic potentials (phenotypic variation).
• Variation may be shown in physical appearance, metabolism, fertility,
mode of reproduction, behaviour, learning and mental ability, and
other obvious or measurable characters.
• Caused by recombination during meiosis and mutation during DNA
duplication.
Variation
is the force behind evolution.
Variation个体变异

11. How evolution occurs
• Mutation
• Natural selection
• Barrier of reproduction
• Speciation

12. Genetic variation
• In the process of replicating DNA,
errors such as mutations occurs
• During meiosis, crossing over and
chromosomal recombination occurs
• Prerequisites for biological evolution
• Undirected, unable to determine the
direction of biological evolution

13. Natural selection
• The variation produced by the
organism will survive if it is more
suitable for the living environment
at that time, and will give birth to
future generations.
• The proportion in the population is
gradually increasing
• Determine the direction of
biological evolution
Directional selection, balanced selection, and disruptive selection. The horizontal axis is the trait and
the vertical axis is the number of individuals. The red line represents the original distribution of traits,
and the blue color is the result of the selection

14. Industrial melanism蛾的工业黑化
• An evolutionary effect prominent in several arthropods, where dark
pigmentation (melanism) has evolved in an environment affected by
industrial pollution, including sulphur dioxide gas and dark soot
deposits.

15. Industrial melanism蛾的工业黑化
• Sulphur dioxide kills lichens, leaving tree bark
bare where in clean areas it is boldly patterned,
while soot darkens bark and other surfaces.
• Darker pigmented individuals have a higher
fitness in those areas as their camouflage
matches the polluted background better; they
are thus favoured by natural selection.

16. Isolation隔离
• Formation of new species
(speciation) occurs in isolation,
usually geographical
• Various groups are unable to
meet or match at the right time
for reproduction
• Accumulation of mutation and
variation
• Finally lost the ability to cross
mating and breeding =
reproductive isolation生殖隔离=
different species

17. Geographical isolation prior reproductive
isolation

19. Ring species
The classical example of the
species ring of the greenish
warbler (Phylloscopus
nitidus). A continuum of
populations live around the
Himalayas. Usually, adjacent
populations would have
similar ethological patterns
and compatible mating calls
(black arrows), but at the
Northern edge of the
distribution, Eastern and
Western populations differ
greatly and behave as two
distinct, reproductively
incompatible, lineages (red
arrows).

20. Reproductive
isolation
• The mechanisms of
reproductive isolation
are a collection of
evolutionary
mechanisms, behaviors
and physiological
processes that prevent
members of different
species from producing
offspring, or ensure that
any offspring are sterile.
• These barriers maintain
the integrity of a species
by reducing gene flow
between related species.

21. Some examples of
prezygotic barriers
合子前屏障

22. Speciation
• Speciation is the
evolutionary
process by which
populations evolve
to become distinct
species.

24. Evidence of evolution
• Paleontology古生物学
• Biogeography生物地理学
• Comparative anatomy比较解剖学
• Embryology胚胎学
• Biochemistry生物化学
• molecular biology分子生物学

25. Evolution
All organisms have a
common ancestor,
but different among
them they have
different evolutionary
relationships

26. Paleontology
• Studying the science of biology and its development in the era of
paleogeology
• Compare the changes of different age organisms by the arrangement of a
series of fossils in sedimentary rocks
• Fossils are remains, remains or traces of life of ancient creatures that
remain in rocks. The older the strata, the simpler the biological structure
This illustration shows an artist’s renderings of species derived
from fossils of the evolutionary history of the horse and its
ancestors. The species depicted are only four from a very diverse
lineage that contains many branches, dead ends, and adaptive
radiations. One of the trends, depicted here, is the evolutionary
tracking of a drying climate and increase in prairie versus forest
habitat reflected in forms that are more adapted to grazing and
predator escape through running.

28. Biogeography
• The study of the distribution of
species and ecosystems in
geographic space and through
geological time
• Geographical isolation promotes
speciation.
• Related species are usually found in
close physical proximity
(supporting the concept of
speciation via gradual divergence).
• Fossils found in a particular region
tend to closely resemble the
modern organisms of the region.

29. Continental drift
• Over 250 million years ago, there was a single continental landmass
(Pangaea) which split into the 6 current land regions
• Closely related species that were separated by the breaking landmass
are localised to regions that were once connected
• For example, ratites (flightless birds) are distributed globally according
to regions that were once part of Gondwanaland

30. Geographic distribution of Bromeliaceae.

31. Most modern marsupials are found almost
exclusively in Australia (~70% of extant species)

34. Comparative anatomy
• Comparative anatomy is the
study of similarities and
differences in the anatomy of
different species.
• 同源器官
• 痕迹器官

35. 同源器官 homologous
organ
• 起源相同
• 位置及基本结构相似
• 形态和功能可能不同
• 例如：猫与鲸的前肢结构。
• 不要和同功器官analogous organ弄混
• 不同物种中的相似结构，因为它们在相似的环境里独立进化，进化通常
是为达到相同或相似的目的，而不是继承自共同的祖先。
• 例如：鼠海豚与鲨鱼的流线身形。它演变于水底的环境，但物种有不同
的祖先。

36. Vestigial organ痕迹器官
• Some species show the
presence of functionless and
reduced remnants of organs
that were once present in their
ancestors.
• Changes to the environment
have rendered these organs
redundant and so over time
they have lost their
functionality
• An example of a vestigial organ
is the pelvic bone in whales –
this bone suggests that whale
ancestors were terrestrial
mammals.

37. Palmaris longus
• Palmaris longus is a muscle found in the
forearm of many mammals, including
humans.
• The Palmaris longus performs different
functions in various animals.
• In some animals it pulls back a skin fold to
expose a claw.
• It is more prevalent in animals which use
their forelimbs to grab things while
climbing, such as orangutans.
• Palmaris longus serves no apparent function
in humans.
• As there is no apparent pressure (positive
or negative) concerning the muscle,
evolution has largely left it alone.
Palmaris longus muscle

38. Nictitating membrane瞬膜
• The nictitating membrane is a transparent or translucent third
eyelid present in some animals that can be drawn across the eye
from the medial canthus for protection and to moisten it while
maintaining vision.

39. Embryology胚胎学
• The study of the prenatal
development of gametes,
fertilization, and development
of embryos and fetuses
• Many animals have common
features during embryonic
development
• Mammals, birds, and reptiles
have cleft palate鳃裂 and tail
during early embryonic
development
out-dated

40. Evolutionary developmental biology （evo-
devo）演化发育生物学
• compares the
developmental processes
of different organisms to
infer the ancestral
relationships between
them and how
developmental processes
evolved.

41. Homologous
hox genes in
such different
animals as
insects and
vertebrates
control
embryonic
development
and hence the
form of adult
bodies. These
genes have
been highly
conserved
through
hundreds of
millions of
years of
evolution.

43. Biochemistry生物化学
• Study that explores the chemical processes
within and related to living organisms.
• Comparative serology比较血清学
• Human serum is injected as an antigen into
rabbits to produce anti-human antibodies.
• This rabbit anti-human serum is used to check
the serum response of humans and other
mammals.
• The closer the relationship with humans, the
more significant the antigen-antibody reaction,
and the more precipitates that appear when
their serum is mixed with rabbit anti-human
serum.
• Because the closer the relationship with
humans is, the more the serum is similar to
humans, the stronger the antibody response.

45. Molecular biology分子分类学
• Research on biology at the molecular
level covers disciplines such as genetics,
biochemistry, and biophysics.
• The more similar species in the
evolutionary history, the easier it is to
find orthologous同源 proteins, genes,
chromosomes that remains similar.

46. The arrangement of human and mouse genes on
the chromosome is only due to reorganization.

47. • https://www.hhmi.org/biointeractive/lizard-evolution-virtual-lab

48. General process of biological evolution
• The structure of the original primitive living entity that appeared on
the earth may be more similar to the existing virus, bacteria, and
yeast?
• Is the original life‘s anabolism同化作用 is autotrophic or heterotrophic?
Is the catabolism异化作用/代谢 aerobic or anaerobic?
• The way in which primitive life is reproduced may be similar to the
reproduction in a virus or the division in bacteria?

49. Stratigraphic analysis地层分析
• Earth age is about 4.6
billion years
• According to stratigraphic
analysis, the emergence
of life was about 4 billion
years ago.

50. Earliest life
• The earliest life may have
originated from RNA
molecules that are capable
of self-replication.
• Since natural selection
favors more efficient
molecules in replication,
DNA is becoming the most
important replica.
• They then begin to
develop within the
membrane, which has a
more stable physical and
chemical environment that
forms the original cells.

51. Anaerobic heterotrophic organism
• There is no free oxygen in
the atmosphere at this
time.
• Prokaryote uses organic
matter as a nutrient for
anaerobic respiration.

52. Autotrophs
• Autotrophic due to mutation
and natural selection
• Prokaryote
• Cyanobacteria
• Photosynthesis
• Release oxygen
• Increase the oxygen content of
the atmosphere
疊層石Stromatolites
Shark Bay, Australia

54. Aerobic organisms
• Increased atmospheric oxygen
content
• Aerobic organism
• Aerobic respiration – releasing
more energy
• High metabolic efficiency

55. Eukaryotes
• Function and structure
are more complex than
prokaryotic cells
• The beginning of mitosis
• Basis of sexual
reproduction

58. Classification of living things
• Taxonomy is the science of defining and naming groups of biological
organisms on the basis of shared characteristics.
• Kingdom is the second highest taxonomic rank, just below domain.
Linnaeus
1735[56]
Haeckel
1866[57]
Chatton
1925[58]
Copeland
1938[59]
Whittaker
1969[60]
Woese et al.
1990[61]
Cavalier-
Smith
1998[54]
Cavalier-
Smith
2015[62]
2 kingdoms 3 kingdoms 2 empires 4 kingdoms 5 kingdoms 3 domains
2 empires, 6
kingdoms
2 empires, 7
kingdoms
(not
treated)
Protista
Prokaryota Monera Monera
Bacteria
Bacteria
Bacteria
Archaea Archaea
Eukaryota
Protoctista Protista
Eucarya
Protozoa Protozoa
Chromista Chromista
Vegetabilia Plantae Plantae
Plantae Plantae Plantae
Fungi Fungi Fungi
Animalia Animalia Animalia Animalia Animalia Animalia

59. The five kingdom classification system
五界分类系统
• Proposed by American biologist R. H.
Whittaker (1924-1980) in 1969.
• On the basis of distinguishing
between plants and animals,
prokaryotes and eukaryotes, Weitek
has divided the biological world into
five kingdoms: Monera原核生物界,
Protista原生生物界, Plantae, Fungi, and
Animalia.

63. 等级式分类法
hierarchy classification
• Organisms are grouped according to
the similarities and differences of
biological traits
• Reflects relationships and evolutions
among species
• The lower the level category, the more
characteristics the members of the
group share

65. binomial nomenclature双名法
• A formal system of naming species of living
things formally introduced by by Carl Linnaeus.
• Each a name composed of two parts, both of
which use Latin grammatical forms.
• The first part of the name – the generic name –
identifies the genus to which the species belongs,
while the second part – the specific name or
specific epithet – identifies the species within
the genus.
• In modern usage, the first letter of the first part
of the name, the genus, is always capitalized in
writing, while that of the second part is not.
• Both parts are italicized when a binomial name
occurs in normal text (or underlined in
handwriting).

66. 使用双名法的好处
• Simplicity and versatility:
• The same name is common in all
languages, avoiding the difficulty
of translation;
• Avoid confusion of the same
name or heterogeneous name;
• Any one species can be clearly
identified by two words;

67. Dichotomous identifying key二叉式检索表
• Most commonly used key
• Two options are available
for each step
• According to the obvious/
diagnostic characters of a
certain aspect of the
organism, split into two
groups
• Subdivided until a final
conclusion is reached

69. 1. (a) 短頸........................................... 2
(b) 長頸........................................... 3
2. (a) 藍色翅膀.................................... 普通翠鳥
(b) 啡色翅膀.................................... 池鷺
3. (a) 白色翅膀.................................... 4
(b) 黑色翅膀.................................... 5
4. (a) 匙羹狀的喙................................ 黑臉琵鷺
(b) 窄長的喙.................................... 大白鷺
5. (a) 粉紅色腳.................................... 黑翅長腳鷸
(b) 黑色腳....................................... 鸕鷀

71. Human Evolution
• Seven or eight million
years ago
• Climate change
• The forest was replaced by
grassland
• Transformed to a
upstanding, two-legged
walking life
• Use and manufacturing
tools
• Form language and society

72. Four stages of human evolution
• Australopithecus
afarensis
• Homo habilis
• Homo erectus
• Homo sapiens
南方古猿
能人
直立人
智人

74. Australopithecus南方古猿
• 4.2 to 1 million years ago
• Walking upright
• Small brain 450 – 530 mL
• Like chimpanzee

75. Homo habilis能人
• 2.4 to 1.7 million years ago
• skull walls became thinner
• skull volume increased ~ 680mL
• Use stone tools

76. Homo erectus直立人
• 1.8 to 0.2 million years ago
• Java man, Peking man
• Larger brain 1088mL
• Upper and lower extremities have well
differentiated.
• Primitive phenotype: retreating
foreheads, massive bony ridges over
the eyes
• Better tools
• Use fire: warmth, chase away animals,
cooking - nutrition

77. Homo sapiens智人
• about 0.2 million years ago
• stand upright completely
• Large brain 1360mL
• Manufacture of fine stone and
bone tools
• Build weapons, set traps
• Friction firing, building houses
• Sewing clothing, artistic taste

78. Development of H. sapiens
• Early H. sapiens
• Neanderthal man in
Germany
• Maba Man马坝人 in China
• Late H. sapiens
• Cromagnon man in France
• Upper cave man山顶洞人 in
China

81. • http://m.mofangge.com/html/qDetail/09/g3/201201/k95cg30991079
.html