• Welcome
• Introduce Zoology
• Syllabus
• Lecture – Evolution, and Zoology– Theory of Evolution by Natural Selection– Origin of Species– Properties of Life Origins of Life– Prokaryotic and Eukaryotic – Levels of organization– Cell division and inheritance
• Biology is the study of Life
• Single cell to multicellular organisms
• Cell is the basic unit of life
• Unique plant cell and animal cell
• Zoology- zoon, animal + logos, to study – is the study of Animals
• Is one of the broadest fields in all of science– Variety of animals– Complexity of and the processes
Specializations in Zoology
• Anatomy
• Ecology
• Genetics
• Parasitology
• Physiology
• Entomology-
• Ichthyology-
Ichthyologist-work to understand structure, function, ecology and evolution of fishes
Studies have uncovered an amazing diversity of fishesCichlid (‘sick-lid’)- freshwater perch-like fishes• 1000 species in Africa• 300 in South America• 3 in India• 1 in North America
Members of this group
• Variety of color patterns
• Habitats
• Body forms
• Feeding habits
Eretmodus
Nip algae with chisel-like teeth
Tanganicodus
Insect pickers
Perissodus
Scale eaters
• Brood their young
• Dogtooth cichlid
The Fontosa
Body form
An Evolutionary Perspective
• Share a common evolutionary past and evolutionary forces that influence their history – Resulted in 4 to 100 million species of animals
• Understand evolutionary process to understand – What it is – How it originated
Lamarck’s Theory of Evolution
• Lamarck hypothesized that species evolve– Through use and disuse and the inheritance of acquired
traits– But the mechanisms he proposed are unsupported by
evidence
Figure 22.4
Fossils, Cuvier, and Catastrophism
• The study of fossils– Helped to lay the groundwork for Darwin’s ideas
• Fossils are remains or traces of organisms from the past– Usually found in sedimentary rock, which appears in
layers or strata
Figure 22.3
• Darwin’s interest in the geographic distribution of species
– Was kindled by the Beagle’s stop at the Galápagos Islands near the equator west of South America
Figure 22.5
EnglandEUROPE
NORTHAMERICA
GalápagosIslands
Darwin in 1840,after his return
SOUTHAMERICA
Cape ofGood Hope
Cape Horn
Tierra del Fuego
AFRICA HMS Beagle in port
AUSTRALIA
TasmaniaNewZealand
PACIFICOCEAN
An
des
ATLANTICOCEAN
Darwin’s Focus on Adaptation
• As Darwin reassessed all that he had observed during the voyage of the Beagle– He began to perceive adaptation to the environment and
the origin of new species as closely related processes
• From studies made years after Darwin’s voyage– Biologists have concluded that this is indeed what
happened to the Galápagos finches
Figure 22.6a–c
(a) Cactus eater. The long,sharp beak of the cactusground finch (Geospizascandens) helps it tearand eat cactus flowersand pulp.
(c) Seed eater. The large groundfinch (Geospiza magnirostris)has a large beak adapted forcracking seeds that fall fromplants to the ground.
(b) Insect eater. The green warbler finch (Certhidea olivacea) uses itsnarrow, pointed beak to grasp insects.
• In 1844, Darwin wrote a long essay on the origin of species and natural selection– But he was reluctant to introduce his theory publicly,
anticipating the uproar it would cause
• In June 1858 Darwin received a manuscript from Alfred Russell Wallace– Who had developed a theory of natural selection
similar to Darwin’s
• Darwin quickly finished The Origin of Species– And published it the next year
Resistance to the Idea of Evolution
• The Origin of Species– Shook the deepest roots of Western culture– Challenged a worldview that had been prevalent for
centuries
Descent with Modification
• The phrase descent with modification– Summarized Darwin’s perception of the unity of life– States that all organisms are related through descent from
an ancestor that lived in the remote past
• In the Darwinian view, the history of life is like a tree
– With multiple branchings from a common trunk to the tips of the youngest twigs that represent the diversity of living organisms
Figure 22.7
Hyracoidea(Hyraxes)
Sirenia(Manatees
and relatives)
Yea
rs a
goM
illio
ns
of y
ea
rs a
go Dei
no
ther
ium
Ma
mm
ut
Ste
go
don
Ma
mm
uth
us
Pla
tyb
elo
don
Bar
yth
eriu
m
Mo
eri
ther
ium
Elephasmaximus
(Asia)
Loxodontaafricana(Africa)
Loxodontacyclotis(Africa)
Natural Selection and Adaptation
• Evolutionary biologist Ernst Mayr– Has dissected the logic of Darwin’s theory into three
inferences based on five observations
• Observation #1: For any species, population sizes would increase exponentially– If all individuals that are born reproduced successfully
Figure 22.8
• Observation #2: Nonetheless, populations tend to be stable in size– Except for seasonal fluctuations
• Observation #3: Resources are limited
• Inference #1: Production of more individuals than the environment can support– Leads to a struggle for existence among individuals
of a population, with only a fraction of their offspring surviving
• Observation #4: Members of a population vary extensively in their characteristics– No two individuals are exactly alike
Figure 22.9
• Observation #5: Much of this variation is heritable
• Inference #2: Survival depends in part on inherited traits– Individuals whose inherited traits give them a high
probability of surviving and reproducing are likely to leave more offspring than other individuals
• Inference #3: This unequal ability of individuals to survive and reproduce– Will lead to a gradual change in a population, with
favorable characteristics accumulating over generations
Artificial Selection
• In the process of artificial selection– Humans have modified other species over many
generations by selecting and breeding individuals that possess desired traits
Figure 22.10
Terminalbud
Lateralbuds
Brussels sproutsCabbage
Flowercluster
Leaves
Cauliflower
Flowerandstems
Broccoli Wild mustard Kohlrabi
Stem
Kale
Summary of Natural Selection
• Natural selection is differential success in reproduction– That results from the interaction between individuals that
vary in heritable traits and their environment
• Natural selection can produce an increase over time– In the adaptation of organisms to their environment
Figure 22.11
(a) A flower mantidin Malaysia
(b) A stick mantidin Africa
• If an environment changes over time– Natural selection may result in adaptation to these new
conditions
• Darwin’s theory explains a wide range of observations
• Darwin’s theory of evolution– Continues to be tested by how effectively it can
account for additional observations and experimental outcomes
Evolutionary Processes
• Organic evolution- change in the genetic makeup of populations over time. – Source of animal diversity– Explains family relationships within animal groups
• Charles Darwin
• Published evidence of evolution 1859
• Proposed a mechanism
• Understanding diversity of animal structure and function arose is one of the many challenges
• i.e cichlid scale eaters of Africa
Animal classification and Evolutionary Relationship
• Evolution not only explanation why animals appear and function as they do
• It explains family relationships
• i.e cichlid species– Groups share more of their DNA– Thus resemble each other
– Genetic studies suggest• Oldest African cichlid found in Lakes Tanganyika and Kivu
• These fish invades rivers, lakes Malawi, Victoria and others
• Most rapid known origin of species of any animal groups
Figure 1.3
• The Origin of Species– Focused biologists’ attention on the great diversity of
organisms
Figure 22.1
• Darwin made two major points in his book– He presented evidence that the many species of
organisms presently inhabiting the Earth are descendants of ancestral species
– He proposed a mechanism for the evolutionary process, natural selection
• The Darwinian revolution challenged traditional views of a young Earth inhabited by unchanging species
• In order to understand why Darwin’s ideas were revolutionary– We need to examine his views in the context of other
Western ideas about Earth and its life
• The historical context of Darwin’s life and ideas
Figure 22.2
Linnaeus (classification)Hutton (gradual geologic change)
Lamarck (species can change)
Malthus (population limits)Cuvier (fossils, extinction)
Lyell (modern geology)
Darwin (evolution, nutural selection)
Mendel (inheritance)
Wallace (evolution, natural selection)
1750
American Revolution French Revolution U.S. Civil War
1800 1850 19001795 Hutton proposes his theory of gradualism.
1798 Malthus publishes “Essay on the Principle of Population.”
1809 Lamarck publishes his theory of evolution.1830 Lyell publishes Principles of Geology.
1831–1836 Darwin travels around the world on HMS Beagle.
Darwin begins his notebooks on the origin of species.1837Darwin writes his essay on the origin of species.1844
Wallace sends his theory to Darwin.1858
The Origin of Species is published.1859Mendel publishes inheritance papers.1865
Homology, Biogeography, and the Fossil Record
• Evolutionary theory– Provides a cohesive explanation for many kinds of
observations
Homology
• Homology– Is similarity resulting from common ancestry
Anatomical Homologies
• Homologous structures between organisms– Are anatomical resemblances that represent variations on
a structural theme that was present in a common ancestor
Figure 22.14Human Cat Whale Bat
• Comparative embryology– Reveals additional anatomical homologies not visible in
adult organisms
Figure 22.15
Pharyngealpouches
Post-analtail
Chick embryo Human embryo
• Vestigial organs– Are some of the most intriguing homologous structures– Are remnants of structures that served important
functions in the organism’s ancestors
Molecular Homologies
• Biologists also observe homologies among organisms at the molecular level– Such as genes that are shared among organisms inherited
from a common ancestor
Homologies and the Tree of Life
• The Darwinian concept of an evolutionary tree of life– Can explain the homologies that researchers have
observed
• Anatomical resemblances among species– Are generally reflected in their molecules, their genes,
and their gene products
Figure 22.16
Species
Human
Rhesus monkey
Mouse
Chicken
Frog
Lamprey14%
54%
69%
87%
95%
100%
Percent of Amino Acids That AreIdentical to the Amino Acids in aHuman Hemoglobin Polypeptide
Biogeography
• Darwin’s observations of the geographic distribution of species, biogeography– Formed an important part of his theory of evolution
Sugarglider
AUSTRALIA
NORTHAMERICA
Flyingsquirrel
Figure 22.17
• Some similar mammals that have adapted to similar environments– Have evolved independently from different ancestors
The Fossil Record
• The succession of forms observed in the fossil record– Is consistent with other inferences about the major
branches of descent in the tree of life
Binomial nomenclature
• Karl von Linne (1707-1778)
• Named and classified plants into hierarchy of relatedness
• Binomial Nomenclature- systematic way of naming organisms- – Two part name describes each kind of organism– First part- indicates the genus– Second part indicates the species to which the organism
belongs.
– i.e. Perissodus microlepis
• The Darwinian view of life– Predicts that evolutionary transitions should leave
signs in the fossil record
• Paleontologists– Have discovered fossils of many such transitional
forms
Figure 22.18
What Is Theoretical about the Darwinian View of Life?
• In science, a theory– Accounts for many observations and data and attempts to
explain and integrate a great variety of phenomena
Figure 1.4
Hierarchy of Relatedness
• Evolutionary concepts hold the key to understanding – why animals look and act – Habitat– Characteristics
Ecological Perspective
• Ecology- (Gr. okois, house + logos, to study)
• Study of the relationships between organisms and their environment
• Human dependence on animals (food, medicine, clothing)
• Humans upset the delicate ecological balances that has evolved
In the 1950’s in an attempt to increase the lake’s fishery
• Nile perch introduced into Lake Victoria
• Reduced cichlid population from 99% to <1%
• Most cichlid feed on algae, the algae grew
• Algae died and decayed
• Lake depleted of oxygen
• Introduced nonnative plant (water hyacinth)
• Water hyacinth has overgrown and resulted in further habitat loss
Figure 1.6 (a)
Figure 1.6 (b)
EC Figure
Chapter 1 Evolution, Ecology and
Zoology
Chapter 4Theory of Evolution by
Natural SelectionMicroevolution and
Macroevolution
Chapter 2Properties of Life Origins of
LifeProkaryotic and Eukaryotic
Levels of organizationCell division and inheritance
Chapter 3MitoticMeiosis