Vertebrate Zoology Lecture Exam 1

*NOT DONE* Only lectures 1-5

What is the most abundant species of vertebrates?

Fish; 33,000 species

Extant

living species

Extinct

dead species

How old is Earth?

\~4 billion years old

When do the first vertebrates appear?

\~500 million years ago

Why are certain animals similar (example: tree frog & toad)

Common ancestor

Why is there diversity among animals?

The environment causes them to adapt

How was grouping done historically?

“Phenetics”; groups are generated based on “similarities” (similar characteristics)

How is grouping done in modern times?

“Cladistics”; groups are generated based on relatedness, “common ancestor”

Why phylum are vertebrates in?

Phylum Chordata

Does Phylum Chordata contain invertebrates?

Yes, some invertebrates

What are the chordate characteristics?

Notochord, dorsal nerve cord, pharyngeal gill slits/pouches, post-anal tail

What is a notochord?

A semi-rigid group of cells that are surrounded by fibrous and elastic tissues; NOT the vertebral column

What are the advantages of a notochord?

Gives support and allows for body movement

What is considered the simplest/most primitive vertebrate?

Hagfish

How is the hagfish unique?

The notochord persists throughout life, has a fibrous & cartilaginous skeleton (no bones), jawless, has no paired appendages, has a poorly developed brain & reproductive system (one gonad)

Do humans have a notochord?

We have bits and pieces; we possessed it during embryonic development

Do humans have pharyngeal gill slits/pouches?

We have pouches during embryonic development

What does the post-anal tail facilitate?

Movement and stability

Do humans have a post-anal tail?

During embryonic development

What are other general chordate characteristics? (not main 4)

Segmented muscle masses, endoskeletons, bilateral symmetry, closed circulatory system

What are the types of diversity?

Structural diversity, Ecological diversity, Physiological diversity, Temporal diversity

“Gonochoristic” species (ex. cardinals)

2 separate sexes

“Simultaneous Hermaphrodite” (ex. hamlet fish)

Both sexes @ same time

“Sequential Hermaphrodite” (ex. anemone fish & bluehead wrasse)

Sequentially changes from male to female (and vice versa)

Pathogenic species (ex. whiptail lizard)

Eggs develop without fertilization

Temperature-Dependent Sex Determination (ex. leopard gecko)

The temperature of the environment and egg determines the sex of the offspring

Precambrian

There’s not a lot of terrestrial environment, mostly aquatic; invertebrates

Cambrian Period

Cambrian Explosion = causes an increase in the # of species

Start of the Paleozoic Era

Increase of invertebrate species

At the end of the Cambrian, the first vertebrates appear (jawless fishes)

\~500 million years ago

Silurian Period

Jawed fishes appear (placoderms & acanthodians)

Abundance of jawed & jawless fishes

Increase in terrestrial plants

410 million years ago

Devonian Period

“**Age of Fishes”**

**Jawed & jawless fishes in both salt & fresh water**

360-400 million years ago

Dunkleosteus/Placoderm

**Sharks are present**

**First terrestrial forests**

**First winged insects**

**First amphibian-like tetrapods**

Permian Period

End of Paleozoic

**Reptiles begin radiating**

**First mammal-like reptiles**

* **Dimetrodon (not a dinosaur)**

**Mass extinction = allows habitats to open up**

* 90% of marine invertebrates & 70% of terrestrial animals go extinct

**Amphibian-like tetrapods on land**

Mesozoic Era

Means “middle animals”

“Age of Reptiles”

Divided into three periods


1. Triassic Period
2. Jurassic Period
3. Cretaceous Period

\~200-250 million years ago

Radiation of reptiles = increased variety & abundance

How is the Mesozoic Era divided?

Triassic, Jurassic, Cretaceous

Theropods

Carnivorous tetrapods that are up-right on their back 2 legs

Sauropods

Herbavores

When do pterosaurs first appear?

Late Triassic, they become extinct in the late Cretaceous

What animals other than reptiles appear during the Mesozoic Era?

Early birds & mammals

What is the first bird in fossil records?

Archaeopteryx

Archaeopteryx

A **bird with reptilian characteristics** (has teeth and actual tail)

In the Mesozoic era, are birds and mammals proliferant?

No; mammals specifically are small insectivores

When does the KT Mass Extinction happen?

At the **end of the Cretaceous period of the Mesozoic era**

KT Mass Extinction

**Asteroid impact**; makes the Earth a bad environment for many species but many species also survive in the newly opened niches

Cenozoic Era

“Recent/New Animals”

“Age of Mammals”

Two periods

* Tertiary Period
* Quaternary Period

Tertiary birds radiate

What groups proliferate/radiate in the Cenozoic Era?

Mammals & birds proliferate/radiate

What was the prevailing opinion of speciation during the 1700s?

“Animals & plants were fixed, invariable, & were created when the Earth & they did not change over time.”

Carolus Linnaeus

“Father of Taxonomy”

*Systema Naturae*

Developed:

* Linnaean Hierarchical Classification System
* Binomial Nomenclature

Jean Baptiste de Lamarck

Theory of “Inheritance of Acquired Characteristics”

Transmutation Theory

Lamarckism

What does Lamarck’s theory of “inheritance of acquired characteristics” hypothesize?

1. **Animals acquire characteristics during their lifetime & pass the characteristics on to offspring.**


1. Animals are always progressing toward a **higher form** (all changes are for the good of the animal)

What was the name of the ship that Darwin was on for a 5 year voyage?

H.M.S. Beagle

What books does Darwin take with him on the voyage?

“Principle of Geology” and “An Essay on the Principle of Population”

Who wrote “Principle of Geology”?

Sir Charles Lyell

What is Sir Charles Lyell referred to?

The Father of Modern Geology

Who wrote “An Essay on the Principle of Population”?

Thomas Malthus

What is Thomas Malthus known for?

“Survival of the Fittest”

“More humans are produced than can survive. Therefore there is a ‘struggle for survival’.”

Who is known for “uniformitarianism”/”gradualism”

Sir Charles Lyell

What does “uniformitarianism”/”gradualism” suggest?

The world has undergone slow & gradual geological processes over millions of years

Who’s work contributes to the initial development of the geologic time scale based on strata?

Sir Charles Lyell

During the initial development of the geologic time scale, was the age of each strata known?

No

How long does Darwin visit the Galapagos for?

They stay for 5 weeks, Darwin is on shore for 19 days

Galapagos Islands Characteristics

600 miles west of Ecuador, 1 to 4 million years old, volcanic formation, no human habitation until recent times, strong selective forces

Are the Galapagos Islands old?

They are not old in a geologic time scale; they are relatively young (1 to 4 million years old)

What are the strong selective forces of the Galapagos Islands?

Very dry & harsh terrestrial environment with a rich marine environment, but it is cold.

What is the hypothesis for the presence of unique animals of the Galapagos?

Animals that were displaced to the Galapagos were from the mainland of Central or South America have either (1) perished or (2) adapted to the different and unique environment

Does Darwin publish his book “On the Origin of Species by Means of Natural Selection” upon his return of his 5 year voyage?

No, he gradually develops “Theory of Evolution by Natural Selection” and collects data over **23 years**

What book does Darwin publish after returning from his voyage on the H.M.S. Beagle?

“The Voyage of the Beagle”; it makes him famous

What two people explore the Amazon River Basin for 4 years?

**Alfred Russel Wallace** and Henry Walter Bates

After Wallace explore the Amazon River Basin, where does he go next to explore and study?

He travels to the Malay Archipelago to explore Malaysia and Indonesia

Thomas Henry Huxley

“Darwin’s Bulldog”

Supported Darwin’s book and theory publicly

Is Darwin’s “On the Origin of Species by Means of Natural Selection” still accepted today?

Yes; 150+ years later, it remains **an accepted and unifying theory in the study of biology**

What did Darwin’s “On the Origin of Species by Means of Natural Selection” hypothesized?

1. A species is not “static”, **organisms could gradually change over time**
2. Darwin suggested **“phyletic gradualism”**: **change is gradual over time**
3. **Concept of** “common decent”: species could be derived from a **common ancestor**, accounting for “similarities” among different species
4. Concept of **“survival of the fittest”**: more individuals are produced each generation than can survive
5. **Concept of** “natural selection”: nature (environment) determines which individual survives; nature “selects” for traits that are advantageous; **accounts for diversity**

__Provided the concept of evolution, BUT not a mechanism__

Gregor Mendel

“Father of Genetics”

Mendelian Genetics

What did Mendelian Genetics provide?

A basis on how traits are passed on from one generation to the next

What was the evolution of natural selection based on?

The ability to genetically transfer traits from parents to offspring; it’s a combination of **Darwinian Evolution and Mendelian Genetics called Neo-Darwinism**

Evolution

Change in genetic composition over time; the change could be beneficial, deleterious, or “neutral”

Natural Selection

the environment favors traits that are advantageous and increase the fitness of an organism in a given environment

Fitness

Ability to survive and reproduce

How are fossils formed?

An organism must be rapidly covered by sediment to prevent decomposition

What does the fossil record tell us?

1. the abundance and variety of animals & plants has varied over time
2. certain species appear in fossil records & over time certain species go extinct
3. some fossils appear to be transitional species (ex. Archaeopteryx)

Homologous structures

structures that are embryonically related/have the same embryonic origin

Ernst Haeckel

Haeckel’s Biogenetic Law: “Ontogeny Recapitulates Phylogeny”

What does Haeckel’s Biogenetic Law of “Ontogeny Recapitulates Phylogeny” mean?

Suggests that the history of your phylogeny is reflected in your embryonic development

What is a “species” according to Ernst Mayr?

* Has similar characteristics (genetics)
* Is capable of interbreeding
* Reproductively isolated in nature

What is the modern “species” definition?

Genetically distinct and genetically isolated

What are the two types of speciation?

Allopatric and Sympatric

Allopatric Speciation

Geographic isolation leads to speciation

Example: Galapagos Tortoises

Sympatric Speciation

Speciation occurring in the same location

Example: Lake Baikal sculpins

What speciation is hypothesized to have caused Darwin’s Finches?

Both allopatric and sympatric speciation; once on an island, they adapted to different ecological niches

What is the classification of species called?

Systematics/Taxonomy

What is the categories in the Linnaean Hierarchical Classification System?

Kingdom, Phylum, Class, Order, Family, Genus, Species

Primitive Characteristics are present in ___

Present in **ancestral groups**

Also called **pleisiomorphies**

Shared Derived Characteristics are ___

a **new characteristics that is only present in a specific group of organisms**

Also called **apomorphies**

How were species historically grouped/classified?

Traditional Systematics

What is traditional systematics based on?

It was based on **structural** **similarities**

Referred to as **phenetics**

Groups were **based on similarities w/o regard to potential ancestry**

**Some traits were “weighed” more important than others (for classification)**

What is the modern method for classifying/grouping species?

**Cladistics;** classifying based on **relatedness (common ancestry)** based on **“primitive” versus “derived” characteristics**

What two basic characteristics were used for cladistic classification?

1. Primitive characteristic
2. Shared Derived characteristic

Each characteristic is equal in “weight”

What are the groups used in cladistics?

Monophyletic and Paraphyletic groups

Monophyletic group

Group includes all members hypothesized to be derived from a common ancestor

Paraphyletic group

Group that does not include all members hypothesized to be derived from a common ancestor

What are the eras in order from oldest to most recent?

Precambrian, Paleozoic, Mesozoic, Cenozoic