Exam 1

Science

• The intellectual and practical activity encompassing the systematic study of the structure and behavior of the physical and natural world through observation and experiment

  • Does not deal with supernatural things

Scientific Method

1. Question or Observation of some kind

2. Background Research

3. Construct Hypothesis

4. Test with an Experiment/Data

5. Analyze results and draw Conclusions

6. Either your hypothesis is data-supported or false

   1. If it is false, try again

7. In the end, report the results

   1. Peer Reviews

Correlation ___________ mean causation

Does not

We can separate correlation and causation when we conduct the ___________; the __________ brings forth the causation of things

Scientific method

Hierarchy of Scientific Terms for Results (From most important to least important)

1. Theory - Explains the overall picture of why

2. Law - Gives an equation or explanation for why

3. Hypothesis - A possible reason for why

4. Fact - What happened

Zoology

• The scientific study of animal life

• Utilizes technologies and methods from all branches of science

• Seeks to document and systematically organize the diversity of animal life

Two important theories that guide zoology research

• Theory of evolution

• Chromosomal theory of inheritance

What is life?

• No simple definition

• The history of life shows extensive and ongoing change called evolution

• The answer must be based on the common history of life on the Earth

• Life’s history of common descent with modification gives it an identity separate from the nonliving world

  • We trace this common history backward through time from the diverse forms observed today and in the fossil record to a common ancestor that must have arisen 4 billion years ago.

What are the general properties of living systems?

• Chemical Uniqueness

• Complexity and Hierarchical Organization

• Reproduction

• Possession of genetic program

• Metabolism

• Development

• Environmental Interaction

• Movement

Chemical Uniqueness - General Property of Living Systems

Living systems demonstrate a unique and complex molecular organization

Complexity and Hierarchical Organization - General Property of Living Systems

• Living systems demonstrate a unique and complex hierarchical organization

• In living systems, there exists a hierarchy of levels that includes:

  • Macromolecules

  • Cells

  • Organisms

  • Populations

  • Species

Reproduction - General Property of Living Systems

• ____________ is a component of the definition of life

• At each level of the biological hierarchy, living forms reproduce to generate others like themselves:

  • Genes replicate to produce new genes

  • Cells divide producing new cells

  • Organisms reproduce, sexually or asexually, to produce new organisms

  • Populations fragment to produce new populations

  • Species split to produce new species

Possession of Genetic Program - General Property of Living Systems

A genetic program provides fidelity of inheritance

• Nucleic acids

• DNA

• Genetic code

Nucleic acids

Encode the structures of the protein molecules needed for organismal development and functioning

DNA

Long, linear chain of nucleotides

• Stores genetic information

Genetic Code

Correspondence between base sequences in DNA and the sequence of amino acids in a protein

Metabolism - General Property of Living Systems

Living organisms maintain themselves by acquiring nutrients from their environments

• Processes include:

  • Digestion

  • Energy production (respiration)

  • Synthesis of molecules and structures required by organisms

Development - General Property of Living Systems

All organisms pass through a characteristic life cycle

• Describes the characteristic changes that an organism undergoes from its origin to its final adult form

Environmental Interaction - General Property of Living Systems

All animals interact with their environments

• Ecology

• Irritability

Ecology

The study of organismal interaction with an environment

Irritability

Organisms responding to environmental stimuli

Movement - General Property of Living Systems

Living systems and their parts show precise and controlled movements arising from within the system

• Living systems extract energy from their environments permitting the initiation of controlled movements

Movement at the cellular level are required for:

• Reproduction

• Growth

• Responses to stimuli

• Development in multicellular organisms

On a larger scale:

• Entire populations or species may disperse from one geographic location to another over time

Movement of nonliving matter:

• Not precisely controlled by the moving objects

Often involves external forces

First Law of Thermodynamics (Law of Conservation of Energy)

• Energy is neither created nor destroyed by can transformed from one form to another

• All aspects of life require energy and its transformation

Second Law of Thermodynamics

• Physical systems tend to proceed toward a state of greater disorder or entropy

• The ultimate fate of materials in cells is the degradation and dissipation of their chemical bond energy as heat

• Organismal complexity is achieved and maintained only by the perpetual use of dissipation of energy flowing into the biosphere from the Sun

Animals originated in _________

The Precambrian seas over 600 million years ago

Characteristics of animals

• Eukaryotes

• Heterotrophs

• Animals cells lack cell walls

Eukaryotes

Cells contain membrane-enclosed nuclei

Heterotrophs

Cannot make their own food and must rely on external food sources

Principles of Science

• Science is guided by natural law

• Has to be explained by reference to natural law

• Testable against their observable world

• The conclusions of science are tentative and therefore not necessarily the final word

• Falsifiable

The Scientific Method

• The hypothetico-deductive method

  • Requires the generation of hypotheses to potentially answer questions

• Using this method, in general, hypotheses may

  • Predict future observations

  • Be falsified

Hypothesis

• Potential answers to being asked.

• Derived from prior observations of nature or from theories based on such observations

• Often constitute general statements about nature that may explain a large number of diverse observations

• If a hypothesis is a very powerful in explaining a wide variety of related phenomena, it attains the level of theory

  • Theory - highest level in science, is generally accepted

    • Things can be a theory and a fact, example: evolution

Steps of Scientific Method

Observation

Question

Hypothesis formation

Empirical test

• Controlled experiment

• Includes at least 2 groups

  • Test group

  • Control group

Conclusions

• Accept or reject hypothesis

Paradigm

Powerful theories that guide extensive research

Scientific Revolution

The refutement and replacement of a paradigm

Two major paradigms that guide zoological research

• Darwin’s Theory of Evolution

• The Chromosomal Theory of Inheritance

Modern evolutionary theory is strongly identified with ________

Charles Robert Darwin

Darwin’s Theory of Evolution

• Over 160 years old

• Published in On the Origin of Species by Means of Natural Selection in England in 1859

• Darwinism encompasses several different, although mutually compatible theories

• Alfred Russel Wallis - had the same idea as Darwin and sent him a letter

Theories of Darwinism

Ernst Mayr (Harvard University) proposed that Darwinism should be viewed as five major theories:

• Perpetual Change

• Common descent

• Multiplication of the species

• Gradualism

• Natural Selection

Theories of Darwinism - Perpetual Change

• The Living world is neither constant nor perpetually cycling but is always changing

  • The varying forms of organisms undergo measurable change across generations throughout time

  • Documented by the fossil record

  • Theory upon which the remaining four are based

The other four theories of Darwinism are based upon _________

Perpetual Change

Theories of Darwinism - Common Descent

• All forms of life descend from a common ancestor through the branching of lineages

  • Phylogeny

  • Serves as the basis for our taxonomic classification of animals

    • All based on evolution

Phylogeny

Life’s history has the structure of a branching evolutionary tree

Theories of Darwinism - Multiplication of the Species

The evolutionary produces new species by splitting and transforming older ones

Theories of Darwinism - Gradualism

Large differences in atomic traits that characterize disparate species originate through the accumulation of many small incremental changes over very long periods of times

Theories of Darwinism - Naturalism

• A creative process that generates novel forms from the small individual variations that occur among organisms within a population

• Adaptation

Adaptation

• An anatomical structure, physiological process, or behavioral trait that evolved by natural selection and improves an organisms ability to survive and leave descendants

  • Ultimate goal - Leave behind descendants

What was Darwin’s obstacle?

It lacked a successful theory of heredity

Neo-Darwinism

Describes Darwin’s theories as modified by incorporating the Chromosomal Theory of Inheritance - based on Mendelian Laws of Genetics

Foundation of current studies of genetics and evolution in animals

Mendelian Heredity and the Chromosomal Theory of Inheritance

Genetic Approach of Mendelian Heredity and the Chromosomal Theory of Inheritance

• Mating populations of organisms that are true-breeding for alternative traits

• Following hereditary transmission of those traits to offspring

• Leads to evolution as desirable traits are passed on to offspring from one generation to the next

Transmission of traits via Gametes

Genes are regions of chromosomes that contain the recipe for a trait

Diploid individuals have two copies of each gene

Gamete Formation

During gamete formation, paired genes in the parent segregate from each other

Each gamete receives one copy of each gene

When fertilization occurs, the offspring receives one copy of each gene from each parent

Zoologist recognize _______ major phyla of living multicellular animals

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• Survivors of about 100 phyla that appeared 600 million years ago during Cambrian explosion, the most important evolutionary event in geological history

• All major body plans evolved with a few million years due to extensive selection and adaptation processes

• Basic uniformity of all life derives from common ancestry and similar cellular construction

Hierarchical Organization of Animal Complexity

Five major grades of organization are recognized

Each grade is more complex than the previous grade

The five grades are

• Protoplasmic

• Cellular

• Cell-tissue

• Tissue-organ

• Organ-system

Protoplasmic Grade of Organization (Unicellular)

• Unicellular groups are the simplest eukaryotic organisms

• Perform all basic function of life within the confines of a single cell

• Protoplasm contains organelles with specialized functions and diversity among groups is due to varying subcellular components and structures

Cellular Grade of Organization

Form metazoans - multicellular organisms such as volvox

Have greater structural complexity by combining cells into larger aggregates

Cells are specialized parts of the whole organism but cannot live alone

Cells demonstrate division of labor and perform specialized tasks earlier accomplished by subcellular components of unicellular organisms

Cell Tissue Grade of Organization

Cells grouped together into definite patterns or layers to perform a common function as a coordinated unit called tissue

Most cells can still be scattered all around the body

Animals such as jellyfish represent this group and are called eumetazoans

Due to the unique structure of sponges, some scientists still classify them at the cellular level rather than the cell-tissue level

Tissue Organ Grade of Organization

Aggregated tissue now assembled into larger functional units called organs

Organs can be composed of more than one kind of tissue and have specialized functions

• The heart is surrounded by connective tissues

Represented by flatworms

• Organ system grade of organization

  • Several organs work together to perform a common function for the survival of the animal

  • Considered the highest level of organization and associated with most complex animal phyla such as nemerteans, crabs, and chordates

Several organs work together to perform a common function for the survival of the animal

Considered the highest level of organization

Associated with most complex animal phyla such as annelids, arthropods, and chordates

Animal body plans are different in

• Grade of organization

• Body symmetry

  • Symmetry is balance of proportions and the correspondence of size and shape of parts on opposite sides of a median plane

• Number of embryonic layers

• Number of body cavities

Types of animal symmetry

• Spherical

• Radial

• Bilateral

Spherical Animal Symmetry

• Any plane passing through the center and divides the body into mirrored halves

• Best suited for floating and rolling

• Found in unicellular forms but rare in large animals

Radial Symmetry

• Body divided into similar halves by more than two planes passing through longitudinal axis

• Found in sponges, jellyfishes, sea urchins, and related groups

• End of tubular body forms called oral surface while the opposite end forms basal attachment disc called aboral surface

Biradial Symmetry

Variant form of radial symmetry

Have part that is single or paired rather than radial

Only two planes passing through the longitudinal axis that produces mirrored halves

Usually sessile, freely floating, or weakly swimming animals like ctenophores

No anterior or posterior end

Can interact with the environment in all directions

Organism divided along a saggital plane into two mirror portions forming right and left halves

Much better fitted for directional (forward) movement which is advantangeous to an animal moving through its environment head first

Associated with cephalization, which is the differentiation of a head region and the concentration of nervous tissues and sense organs in the front area

Also has mouth in front to allow for more efficient feeding detection of prey

Regions of Bilaterally Symmetric Animals - Anterior

Head end

Regions of Bilaterally Symmetric Animals - Posterior

Tail end

Regions of Bilaterally Symmetric Animals - Dorsal

Back (upper) side

Regions of Bilaterally Symmetric Animals - Ventral

Front (Belly) side

Regions of Bilaterally Symmetric Animals - Medial

Midline of the body

Regions of Bilaterally Symmetric Animals - Lateral

Right and left sides

Regions of Bilaterally Symmetric Animals - Distal

Parts father from the middle of the body

Regions of Bilaterally Symmetric Animals - Proximal

Parts nearer the middle of body

Regions of Bilaterally Symmetric Animals - Frontal Plane (Coronal Plane)

Divides body into dorsal and ventral halves

Regions of Bilaterally Symmetric Animals - Transverse plane (Cross section)

Divides body into anterior and posterior halves

Body Cavities of Animals

• Internal space represented by guy cavity and fluid-filled body coelom that cushions and protects internal organs

• Dependent on mesodermal pouch formation during gastrulation

Types of Body Cavities

• Acoelomate

• Pseudocoelomate

• Coelomate

Acoelomate

No body cavity

Sponges (cellular grade of organization) are acoelomate

• After blastula formation, cells reorganize to form adult body but do not form gastrula

• Cells grow and surround a chamber called spongocoel

• Bastula has no external opening to gut cavity forms

Pseudocoelomate

Partial body cavity

Coelomate

True body cavity

• Development proceeds from blastula to gastrula

• Opening to the archenteron is the blastocoel; becomes the mouth or the anus

• Embryo now has two cavities - gut and blastocoel

• Inside gut is lined by endoderm, outer layer of cells is ectoderm, middle area lined with mesoderm

Protostome Mesoderm Formation

Mesoderm forms as endodermal cells near blastopore migrate into the bastocoel

Three body plans are possible

• Acoelomate plan

• Pseudocoelomate

• Schizocoelous coelomate plan

Protostome Mesoderm Formation - Acoelomate Plan

• Mesodermal cells completely fill the blastocoel so no body space is formed

• Gut is only body cavity

• Region between ectoderm and endoderm is filled with spongy mass of parenchyma cells that are from embryonic connective tissue and are important for transport and disposal of metabolic wastes

Protostome Mesoderm Formation - Pseudocoelomate Plan

• Mesodermal cells line with the outer edge of the blastocoel only partially lined with mesoderm

• Pseudocoelom is a false body cavity

• Two body cavities formed where persistent blastocoel forms pseudocoelom with a gut cavity

Protostome Mesoderm Formation - Schizocoelous Coelomate Plan

• Mesodermal cell fill blastocoel and then splits to form a space called a coelom

  • A true body cavity that is complete lined by mesoderm

• Two body cavities are formed: gut and coelom

Triploblastic Animals Developmental Pathways

• Radial Cleavage

• Spiral Cleavage

Triploblastic Animals Developmental Pathways - Radial Cleavage

• Typically accompanied by three traits

  • Blastopore becomes the anus and the new opening becomes the mouth

  • Coelom formation is by enterocele

  • Cleavage is regulative

• Animals with these features are called deuterostomes

Animals with radial cleavage are called ________

Deuterostomes

Triploblastic Animals Developmental Pathways - Spiral Cleavage

• Produces embryos whose developmental pattern contrast with those of deuterostomes

  • Blastopore becomes the mouth

  • Cleavage is mosaic

  • May be acoelomate, pseudocoelomate, coelomate via schizocoely

• Animals with these features are called lophotrochozoan protostomes

Animals that have spiral cleavage are called _______

Lophotrochozoan Protostomes

__________________ exhibit a range of cleavage patterns including spiral and superficial cleavage and can be coelomate or pseudocoelomate.

Ecdysozoan Protostomes

A few diploblastic and triploblastic form ________

Incomplete gut cavity

• Same opening for entrance for food and exit of wastes

Most common animal groups form a __________

Complete gut cavity

• Allows for one-way flow of food from mouth to anus

• Tube-within-a-tube design is very adaptive to various types of food

Segmentation

Common feature of metazoans

• Serial repetition of similar body segments along longitudinal axis of body

• Each segment is a metamere or somite that contains internal and external structures of several vital organ systems

  • Segments can be seen during early development and also appear as superficial ectodermal and body wall features in adults

  • Permits greater body mobility and complexity of structure and function

  • Found in annelids, arthropods, and chordates

Extracellular Components of an Animal Body

Two categories

• Body fluids that fill up two compartments

  • Intracellular space

  • Extracellular space

• Extracellular structural elements

  • Support connective tissues, cartilage, and cuticle as storage depot and mechanical protection

Extracellular Components of an Animal Body - Intracellular Space

Within body cells

Extracellular Components of an Animal Body - Extracellular Space

Outside of body cells like blood plasms and interstitial fluids

Cellular Components of an Animal Body

Derived from germ layers

Four types of tissues form during embryonic development

• Epithelial Tissue

• Connective Tissue

• Muscular Tissue

• Nervous Tissue

All animals and their organs are made from these four basic tissue types

Cellular Components of an Animal Body - Epithelial Tissue

Sheet of cells that covers an internal or external surface of the animal body

• Internally, function as lining for all organs and ducts as well as all passageways

  • Allow the transport for secretions and various materials to all cells

  • Has modifications to produce lubricating mucus and specialized hormones and enzymes

• Externally, used for protection

• Epithelial cells are classified based on form and number of layers

• Blood vessels never penetrate epithelial tissues, cells depend on diffusion

Cellular Components of an Animal Body - Simple Epithelial Tissue

• Single layer of cells; occur in all metazoans

• Classified based on shape and function

  • Squamosal

  • Cuboidal

  • Columnar

Squamosal Simple Epithelia Tissue

Flattened cells forming continuous lining blood capillaries, lungs, and surfaces allowing diffusion and transport

Cuboidal Simple Epithelia Tissue

Short box-like cells lining the ducts and tubules of kidneys, salivary glands, and other secretory systems

Columnar Simple Epithelia Tissue

Taller than cuboidal with elongate nuclei and many small finger-like projections called microvilli for increased absorption along the intestines