Evidence and Pattern of Evolution Flashcards by Ken Valdellana

are the useless remnants of structures or organs which were prominent and functional in ancestors.
These are often undersized, degenerated and nonfunctional. Man alone possesses nearly 100 vestigial structures.

Vestigial or rudimentay organs

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in man is the remnant of caecum which is
large and functional in herbivorous mammals. It contains bacteria that produce the enzyme cellulase for the digestion of cellulose.

Vermiform appendix

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are used in many mammals
for collecting sound waves from the surroundings. A complete set of muscles for their movements is present in the external ear of man but these muscles are nonfunctional.

Auricular muscles of external ear

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What are the Vestigial Organs in Man

Vermiform appendix
Auricular muscles of external ear
Nictitating membrane or Plica semilunaris
Vestigial Tail Vertebrae
Lobe of the external ear
Wisdom teeth
Canines
Mammary glands in males
Body hair

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is the third eyelid in the inner angle of each eye in man and many mammals. It corresponds to the nictitating membrane but it is completely unstretchable and nonfunctional.

Nictitating membrane or Plica semilunaris

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Early embryo of man possesses an external tail but it is shed off much before the adulthood is attained. Rarely, a child may be born with a short visible tail. In adults the tail is represented by a string of caudal vertebrae, which constitute the coccyx (tail bone).

Vestigial Tail Vertebrae

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is of no practical benefit to man ,
although serve d the purpose of sound gathering in the ancestors
of man.

Lobe of the External ear

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are the third pair of molars. They are vestigial.
These are last to erupt or even fail to erupt.

Wisdom Teeth

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in man are reduced due to taking soft food and noncarnivorous habit.

Canines

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in humans are of no use and are vestigial remains.

Body hair

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Vestigial Organs in Other Animals

Vestigial of Hindlimbs and Pelvic
Vestigial wings
Splint bones
Eyes in deep, dark habitats

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is the reappearance of ancestral
characteristics in an organism or in the organisms of a group, which do not occur normally or which represent the reminiscent of normal structures possessed by the individuals of other groups

Atavism or reversion

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the neck may possess an additional opening through which the throat or nasal cavity communicates with the exterior. This represents the opening of an additional pharyngeal pouch to the
exterior and is known as

Cervical Fistula in Man

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It is devoid of vertebrae and is
removed by surgery with no trouble.

Tail

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The same condition is noted in all the primates but in pigs, these occur in two rows one along either side of the chest and abdomen. Sometimes, extra-mammary glands or nipples appear in man.

Mammary glands

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Man is characterized by scanty hair on the body and no hair on face but in the relatives of man (apes) hair are present profusely. A man was born in Russia with profuse development of hair on the face and body (Irish dogman).

Hair on the Body and Face in Irish Dogman

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Types of Atavism

Family Atavism
Race Atavism
Atavism or Teratology

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It includes sudden reappearance of a character or characters in the offspring after remaining latent in the family for several generations. This phenomenon is controlled at gene
level and can be explained by simple Mendelian laws of inheritance.

Family Atavism

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It includes those cases of reversal where one or more characters of one race appear in the individuals of another race.

Race Atavism

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This includes the appearance in a race of such abnormal characters which were normal in other supposedly ancestral races. The appearance of cervical fistula in man,
which actually corresponds to the gill-slit, or the appearance of external hindlimbs in a humpback
whale or the homodont dentition in piscivorous cetaceans are examples of teratology.

Atavism of Teratology

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had noticed remarkable similarity
among vertebrate embryos, whose adults are markedly different

Von Baer

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was impressed by the generalized pattern of
development and the general resemblances between the embryos of different groups of animals

Ernst Haeckel (1834-1919)

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is the life history of an individual starting from ovum and phylogeny is the evolutionary history of the group

Ontogeny

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which says “Ontogeny recapitulates phylogeny”.

Recapitulation Theory or Biogenetic Law

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All start their life from a fertilized egg called

Zygote

It undergoes repeated cleavages and develops into

morula, blastula, and gastrula

Three germinal layers

ectoderm, mesoderm, and endoderm

refers to the degenerative changes wherein an active larva transforms into a sedentary adult. Adults of certain animals have degenerated features and do not show any resemblance with other animals of their group or any other group. But, their larval forms have helped in establishing their phylogenetic relationship

Retrogressive metamorphosis

It develops gonads, attains sexual maturity and starts reproduction. This is called

Neoteny or paedogenesis

The Recapitulation Theory was first proposed by

Von Baer (1828)

every organism during its development recapitulates in an abbreviated form the evolutionary history of its race. In other terms, an organism repeats its ancestral history during its development.

Recapitulation theory

is the study of fossil remains of plants and animals that lived in the past.

Palaeontology

What is the Latin of "something to dug out"

Jossilum

are actual remains, traces or impressions left by the organisms that lived in the past and got preserved in sedimentary rocks. These include bones, teeth, shells and other hard parts of animals or impressions of plants pressed into shale or insects trapped in tree resin.

Fossils

called the 'Father of Palaeontology'

Leonardo Da Vinci (1452-1519)

'Founding Father of Modern Palaeontology’.

Cuvier (1800)

the process by which organic matter exposed to minerals over a long period is turned into a stony substance

Petrifaction

Types of Fossils

Unaltered remains of entire organisms Petrified fossils (altered fossils) Molds and Casts Prints or Impressions Coprolites

Under exceptionally favourable conditions, the entire animal body gets preserved in ice, petroleum spring, asphalt, resin, amber and oil-soaked ground.

Unaltered remains of entire organisms

are formed by the replacement of organic parts of dead and decaying organisms molecule by molecule by minerals

Petrified fossils (Altered fossils)

Their bodies disintegrate leaving hollow cavities, called

Molds

They get filled with natural deposits of minerals which harden to form exact _______ of the original organism.

Cast

The footprints of animals or impressions of leaves, stems, skin and wings, etc., left in soft mud are preserved when it changes into a rock.

Prints or Impressions

____________ of moving animals left in the soft mud are preserved when the soft mud hardens into rocks, preserving the prints.

Footprints or tracks and trails

These are fossils of fecal matter or droppings. These are found in association with the animal fossils. Their study may provide information pertaining to their food habits.

Coprolites

is the study of distribution of animals and plants on Earth in space and time .

Biogeogrpaphy

The study of geographical distribution of animals is called

Zoogeography

He divided the Earth surface into six biogeographical regions or life zones called realms based on the distribution of birds.

Philip Lutley Sclater (1858)

regions or life zones called

realms

e reorganized these biogeographical realms on the basis of the distribution of terrestrial and freshwater vertebrates

Wallace

Six biogeographical regions or life zones

Neartic Palaearctic Neotropical Oriental Ethiopian Australian

Asia (south of the Himalayas including India, Sri Lanka, Malaya peninsula), Sumatra. Borneo, Java, Celebes and Philippines.

Oriental

can be found in Protopterus in Africa ▫ Neoceratodus in Australia ▫ Lepidosiren in South America

Lungfishes

are found in Africa and India but not in places with identical climate in Brazil.

Elephant

_______ or egg laying mammals occur only in Australian Island while marsupials, the pouched mammals are exclusively found in Australia, New Zealand and South America.

Monotremes

is one which never had any connection with the mainland. It is formed from submerged volcanic mountains which are pushed up above the surface of sea. On being exposed, the mountain peaks cool down providing a suitable surface for animals and plants that reached there.

Oceanic Island

The prominent inhabitants in Galapagos Island

Iguana Giant Land Tortoise Darwin's Finches

While classifying animals, scientists come across certain animals or small animal groups which exhibit characteristics of more than one group. Such animals or animal groups are called

Connecting links

are a connecting link between nonliving and living because they characteristics of both groups.

Viruses

a protozoan that has chlorophyll and chloroplasts like plants. It is holophytic or autotrophic and synthesizes food by photosynthesis

Euglena

a colonial protozoan whose cells are similar to choanocytes or collared cells of phylum Porifera.

Proterospongia

a connecting link between Annelida and Arthropoda because it exhibits characteristics of both phyla.

Peripatus

: belonging to class Monoplacophora of Phylum Mollusca. Its first living specimens were dredged from a depth of 3500 meters off the Pacific Coast of Costa Rica (Mexico)

Neopilina

The science of naming, describing and classifying organisms is known

Taxonomy

allowed the study of blood proteins that helped in tracing phylogenetic relationships

Precipitation method

A method introduced by __________ called the Precipitation Method allowed the study of blood proteins that helped in tracing phylogenetic relationships.

Dr. George H.F. Nuttal

When such molecular changes accumulate at a constant rate, the phenomenon was called

Molecular clock

When such molecular changes accumulate at a constant rate, the phenomenon was called molecular clock by

Zuckerandl and Pauling (1965)

The pattern of substitutions in the nucleotide sequences in globin genes during the entire course of evolution can be laid down in the form of a phylogenetic tree. It represents the evolutionary history of the gene and it closely resembles to the evolutionary relationships predicted by anatomical studies

Phylogenetic trees

The essential component of nucleus in every living cell is the chromatin material or hereditary material that organizes into chromosomes during cell division.

Chromatin

As they are inherited from generation after generation, genes may undergo changes producing

mutations and variation

assembled data from recent surveys conducted in 32 European countries, the United States, and Japan. All the polls had included this question: True or False? Human beings, as we know them, developed from earlier species of animals.

Jon D. Miller et al., 2006

Two models of the history of life on earth

Theory of Special Creation and Theory of Descent with Modification

species are immutable—unchanged since their origin—and variation among individuals is limited. ▪ All species were created separately and are thus genealogically unrelated to each other.

Special Creation

the first scientist to give a biological definition of species, “One species never springs from the seed of another.”

John Ray (1686)

first published in 1859, convinced the scientific community that it was true—that Earth’s species are the products of descent with modification from a common ancestor (Mayr 1964)

On the Origin by means of natural selection

The evidence—some of it presented by Darwin, much of it accumulated since—has convinced virtually all scientists who study life that Darwin was right. Darwin called the pattern he saw

Descent with modification

Each generation, the experimenter examines the population and chooses as breeders only those individuals with the most desirable characteristics.

Selective breeding or artificial selection

Why microevolution matters?

Microevolution is important in human affairs because it alters the nature of the many organisms we interact with. These include domestic plants and animals, wild organisms we eat, microbes that cause disease, parasites, pests, and commensal organisms such as the bacteria that inhabit our guts and help us digest our food. In addition, our interactions with other organisms sometimes cause our own populations to evolve, leading to genetic differences among individuals who live in different places and have divergent lifestyles.

are populations, or groups of populations, within and among which individuals actually or potentially interbreed and outside of which they do not interbreed.

Species

If individuals from different populations have the opportunity to mate but are disinclined to do so, or if such individuals mate but fail to produce healthy, fertile offspring, then the individuals belong to

Different species

A lesson from experiments like Dodd’s is that speciation is typically not a sudden event, but a

gradual process

Why Speciation Matter?

Essay

is any trace of an organism that lived in the past

Fossil

The worldwide collection of fossils is called

Fossil record

He published a list of 23 species known only from fossils. His point was to challenge the hypothesis that unusual forms in the fossil record would eventually be found alive, once European scientists had visited all parts of the globe

Georges Cuvier

was the first to publish a related observation that was later confirmed and elaborated by Darwin

William Clift

The general pattern of correspondence between fossil and living forms from the same locale came to be known as the

Law of Succession

What makes the amphibious blenny Praealticus a transitional form?

It is derived from, and thus represents, a lineage that had evolved some, but not all, of the novel traits that transform an aquatic blenny into a terrestrial one. It shows that an intermediate species, with only some of these traits, is viable. And it indicates that coordinated hopping evolved before tail twisting.

give us a way to test specific hypotheses about macroevolution by making predictions that we can confirm or refute by digging for fossils.

Transitional forms

argued, from detailed anatomical analyses, that the dinosaurs from which birds are most likely derived were theropods—a group of bipedal carnivores that includes Compsognathus, Velociraptor, and Tyrannosaurus rex

John Ostrom (1973)

noted that if Ostrom is correct, then “feathers may have been widespread in bird-like theropods.” The undiscovered fossil record, in other words, should hold theropod dinosaurs with feathers in various stages of evolution. At the time, no such animals were known.

Robert Bakker and Peter Galton (1974)

reported the discovery, in China’s Liaoning Province, of a theropod called Sinosauropteryx. The fossils were the most exquisitely preserved dinosaur remains found to that date. Sinosauropteryx, about the size of a chicken, bore bristly structures on its neck, back, flanks, and tail. Many paleontologists took these bristles to be simple feathers (though this was controversial).

Pei-ji Chen et al., 1998

a group that includes mammals, reptiles, and birds

amniotes

—a group of bipedal carnivores that includes Compsognathus, Velociraptor, and Tyrannosaurus rex.

Theropods

Why macroevolution matters

Macroevolution matters in our everyday lives because our own bodies are its products. As we will see in the next section, our deep ancestry traces back to fish and beyond. Otherwise puzzling aspects of our anatomy and physiology begin to make sense when viewed in an evolutionary context.

The crucial evidence for universal common ancestry is

homology

Britain’s leading anatomist, defined homology as “the same organ in different animals under every variety of form and function.”

Richard Owen

as similarity due to the inheritance of traits from a common ancestor.

homology

Why common ancestry matters

Common ancestry is the conceptual foundation upon which all of modern biology, including biomedical science, is built. Because we are descended from the same ancestral lineage as monkeys, mice, baker’s yeast, and even bacteria, we share with these organisms numerous homologies in the internal machinery of our cells. This is why studies of other organisms can teach us about ourselves.

m is the claim that geological processes taking place now worked similarly in the past. It was a direct challenge to catastrophism, the hypothesis that today’s geological formations resulted from catastrophic events in the past on a scale never observed now.

Uniformitarianism

Why Earth's Age matters?

The extreme age of Earth and of life matter, because descent with modification is a slow process. New evidence and discoveries in various fields including biology and geology only make sense in the view that the Earth and life on it are at least a few billion years old.