Zoology Exam #1 Flashcards
1
Q
Zoology
A
The scientific study of animal life
2
Q
Principles of modern zoology
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- Theory of evolution
- Chromosomal theory of inheritance
3
Q
General Properties of Living Systems
A
- Chemical uniqueness
- Complexity and hierarchical organization
- Reproduction
- Possession of a genetic program
- Metabolism
- Development
- Environmental interaction
- Movement
4
Q
Characteristics of animals
A
Eukaryotes: cells contain membrane-enclosed nuclei
Animal cells lack cell walls
5
Q
Theories of Darwinism
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- Perpetual change
- Common descent
- Multiplication of species
- Gradualism
- Natural selection
6
Q
Perpetual Change
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The living world is neither constant nor perpetually cycling, but is always changing
7
Q
Common Descent
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All forms of life descend from a common ancestor through a branching of lineages
8
Q
Multiplication
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The evolutionary process produces new species by splitting and transforming older ones
9
Q
Gradualism
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Large differences in anatomic traits that characterize disparate species originate through the accumulation of many small incremental changes over very long periods of time
10
Q
Natural Selection
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A creative process that generates novel forms from the small individual variations that occur among organisms within a population
11
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Adaptation
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An anatomical structure, physiological process, or behavioral trait that evolved by natural selection and improves an organism’s ability to survive and leave descendants
12
Q
Neo-Darwinism
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Describes Darwin’s theories as modified by incorporating the Chromosomal Theory of Inheritance- based on Mendelian Laws of Genetics
13
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Amphiphilic
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Compounds that are polar and water-soluble on one end and non-polar on the other end
- form semi-permeable membranes
14
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Early Atmosphere
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- Water vapor
- CO2
- H2
- CH4
- NH3
- No free oxygen
15
Q
Present Atmosphere
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- Strongly oxidizing
- Molecules necessary for life cannot be synthesized outside of the cells
- Not stable in the presence of O2
16
Q
Stanley Miller and Harold Urey
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Successfully simulated the Oparin-Haldane hypothesis
17
Q
Origin of living systems
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Life on earth: 4 billion years ago
First cells would have been autonomous, membrane-bound units capable of self-replication requiring nucleic acid
18
Q
Origin of Metabolism
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Earliest organisms
- probably primary heterotrophs
- derived nutrients from environment
- anaerobic bacterium-like
- no need to synthesize own food
19
Q
Evolution of Autotrophs
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- more heterotrophs, less food source
- autotrophs gain selective advantage
- organisms gain enzymes to catalyze conversion of inorganic molecules to more complex ones
20
Q
Appearance of Photosynthesis and Oxidative Metabolism
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- autotrophy evolved in the form of photosynthesis
21
Q
Photosynthesis Affected Atmosphere
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- Changed from reducing to a highly oxidizing one
- oxidative metabolism appeared using oxygen as the terminal electron acceptor and completely oxidizing glucose to carbon dioxide and water
22
Q
Appearance of Eukaryotes
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Single-celled eukaryotes arose 1.5 billion years ago- protozoans or protists
- membrane-bound nucleus
- more DNA
- has more organelles in cytoplasm
23
Q
Lynn Margulis
A
propose that eukaryotes resulted from a symbiotic relationship between two or more bacteria
24
Q
A legacy of change
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every feature of life as we know it today is a product of evolution
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Darwinian Evolutionary Theory
Charles Darwin and Alfred Russel Wallace first established evolution as a powerful scientific theory
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Lamarckism
Jean Baptiste de Lamarck
- authored 1st complete explanation of evolution before Darwin
- made case that fossils were remains of extinct animals
- proposed inheritance of acquired characteristics
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Inheritance of Acquired Characteristics
Lamarckism- organisms strive to meet demands of the environment, acquire adaptations individually and then pass them to offspring
NOT accepted now
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Charles Lyell
Geologist who established the principle of uniformitarianism, showed that natural forces acting over long periods of time can explain fossil-bearing rocks
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Lyell's Uniformitarianism
- Laws of physics and chemistry have not changed throughout Earth's history
- Past geological events occurred by natural processes similar to those observed today
Gradual accumulation of small increments of change that have no particular direction
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Interpreting the Fossil Record
- Many organisms left no fossils so the fossil record is incomplete
- Fossils form in stratified layers
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Evolutionary Trends
Directional changes in features and diversity of organisms
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Common Descent
Darwin proposed that all plants and animals descended from a common ancestor
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Homology
"the same organ in different organisms under every variety of form and function"
- Richard Owen
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Phylogenetic Reconstruction
The pattern formed by the sharing of homologies among species provides evidence for common descent and allows us to reconstruct the branching evolutionary history of life
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Ontogeny
The development of an organism through its entire life
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Recapitulation (Ernst Haeckel)
Proposed that ontogeny recapitulates phylogeny
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Heterochrony
Evolutionary change in timing of development
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Multiplication of Species
Darwin's theory postulates that genetic variation present within a species, especially between geographically separated populations, provides the material from which new species are produced
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What is a Species?
- members descend from a common ancestral population
- interbreeding occurs within a species but not among different species (reproductive barriers)
- Genotype and phenotype within a species is similar
- abrupt differences occur between different species
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Reproductive Barriers
Biological features that prevent different species from interbreeding
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Allopatric Speciation
Allopatric populations occupy separate geographical areas
- cannot interbreed because they are separated but could do so if geographic barriers were removed
- Allopatric Speciation occurs when allopatric populations evolve reproductive barriers
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Causes of Allopatric Speciation
- Vicariant speciation- occurs when climate or geology causes populations to fragment
- Founder effect- occurs when a small number of individuals disperse to a distant place and form new populations
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Nonallopatric Speciation
Occurs without prior geographic separation of populations (may occur via sympatric or parapatric speciation)
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Sympatric Speciation
Different individuals within a species become specialized for occupying different components of the environment
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Parapatric Speciation
Occurs when two species are separated by their geographic ranges but make contact along a borderline that neither species successfully crosses
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Adaptive Radiation
The evolution of several ecologically diverse species from a common ancestral species within a short geological time interval
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Gradualism
Darwin's theory of gradualism opposes arguments for the sudden origin of species
- based on the accumulation of small changes over time which led to the different major forms of life
- agreed with Lyell's uniformitarianism that past changes do not depend on catastrophic events not seen today
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Punctuated Equilibrium
Niles Eldridge and Stephen Jay Gould
- Explains the discontinuous evolutionary changes observed through geological time (incomplete fossil records)
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Components of Natural Selection
Two-Part Process
- Random component: random production of variation among organisms, mutation does not preferentially generate favorable traits
- Nonrandom component: survival of different traits depending on environmental resources
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Neo-Darwinism
Biggest weakness of Darwin's theory was lack of inheritance mechanism
- saw inheritance as a blending of parental traits
- believed an organism could alter its heredity through use and disuse of parts following Lamarckism
- environment has direct influence on body parts
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Modern Darwinism
Mendelian genetics eventually clarified the particulate inheritance idea that Darwin's theory of natural selection required
- population genetics
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The Modern Synthesis
Two Levels
- Microevolution: genetic variation and change within a species of natural population, evolutionary changes in frequencies of different allelic forms of genes
- Macroevolution: evolution on large scale events, origins of new structures and designs, trends, mass extinctions, and so on
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Microevolution
Polymorphism is the occurrence of different allelic forms of a gene in a population
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Forces of Evolutionary Change
Factors that can alter allele frequencies in a gene pool
- recurring mutations
- genetic drift
- migration
- natural selection
- interactions of all of the above
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Evolutionary Response of Quantitative Traits
Stabilizing Selection
Directional Selection
Disruptive Selection
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Macroevolution
Large-scale events in organic evolution as seen in the fossil record
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Specialized Feeding
Restricted food sources usually found in limited habitats
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Generalized Feeding
Feed on a variety of food sources and found everywhere
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Mass Extinction
Periodic events where huge numbers of taxa go extinct
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Major Extinction Events
- Permian Extinction- 245 million years ago
- Cretaceous Extinction- 65 million years ago
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Catastrophic Species Selection
Usually affects certain lineages favored by selective challenges different from normal earth's history
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Preformation
Concept of a miniature adult being present in the sperm or egg, waiting to unfold
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Epigenesis
Demonstrate there was no preformed chick in the early egg, undifferentiated granular material became arranged into layers, layers thickened, thinned, and folded to produce the embryo
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Current Ideas of Development
Development is a series of progressive changes in an individual from its beginning to maturity, begins when a fertilized egg divides mitotically to produce multi-celled embryo
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Progressive Subdivision
- Cytoplasmic Specification
- Induction
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Cleavage and Early Development
During cleavage the embryo divides repeatedly
- both nuclei and cytoplasm divides completely
- zygote starts to become multicellular but does not produce uniform cells
- Large cytoplasmic mass converted into small maneuverable cells- called blastomeres
- no cell growth occurs, only subdivision until cells reach regular somatic cell size
- original cytoplasm is continuously divided into smaller units
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Vegetal Pole
Formed by the presence of yolk at only one end
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Isolecithal Eggs
- very little yolk distributed evenly in cytoplasm
- cleavage is holoblastic
- found in echinoderms, tunicates, cephalochordates, mollusks, and mammals
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Holoblastic Cleavage
- cleavage furrow extends completely through the egg
- direction of dividion can be radial, spiral or rotational
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Mesolecithal Eggs
- Moderate amount of yolk concentrated in the vegetal
- holoblastic cleavage
- amphibians
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Centrolecithal Eggs
- much yolk concentrated in the center
- cleavage is meroblastic
- occurs in arthropods
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Telolecithal Eggs
- much yolk concentrated at vegetal pole
- cleavage is meroblastic
- found in reptiles, birds, fishes, amphibians
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Meroblastic Cleavage
- cleavage furrow does not cut through the heavy yolk
- cleavage is confined to a narrow disc on top of the yolk following a discoidal direction
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Development Following Cleavage
cleavage creates cluster of cells (blastula), then gastrula stage with 1 or 2 more germ layers
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Gastrulation
- results in the formation of germ layers
- involves an invagination of one side of blastula
- forms a new internal cavity called gastrocoel
- opening into second cavity called blastopore
- gastrula has an outer layer of ectoderm and an inner layer of endoderm
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Blind/ incomplete Gut
when the embryonic gut opens only into the blastopore
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Complete Gut
complete pathway from mouth to anus
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Formation of complete gut
formed with the inward movement of the archenteron until it reaches the ectodermal wall of the gastrula
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Grades of Organization
- Protoplasmic- unicellular, perform all functions of life within one cell
- Cellular- greater structural complexity, cells are specialized parts of the whole, cannot live alone, cells demonstrate division of labor
- Cell-Tissue- cells grouped in definite patterns to form common function- tissue
- Tissue-Organ- tissues now assembled into functional units-organs, can be more than one type of tissue, have specialized functions
- Organ-system- several organs work together to perform common function, highest level of organization
80
Radial Symmetry
body divided into similar halves by more than two planes passing through longitudinal axis
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Spherical Symmetry
any plane passing through the center and divides body into mirrored halves
81
Eumetazoans
Jellyfish, multicellular
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Biradial Symmetry
have a part that is single or paired rather than radial, only two planes passing through the longitudinal axis that produces mirrored halves
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Bilateral Symmetry
organism divided along a sagittal plane into two mirror portions forming right and left halves
84
Types of Body Cavities
- Acoelomate- no body cavity (sponges)
- Pseudocoelomate- partial body cavity
-Coelomate- true body cavity
85
Body Cavity Formation
Sponges
- after blastula cells reorganize to form adult body, but do not form gastrula
- cells grow and surround a chamber called spongocoel
- blastula has no external opening so no gut cavity forms
Other animal phyla
- development proceeds from blastula to gastrula
- opening to archenteron is the blastocoel- becomes mouth or anus
- embryo has two cavities (gut and blastocoel)
- 3 germ layers
86
Protostome Mesoderm Formation
Mesoderm forms as endodermal cells near blastopore migrate into the blastocoel
3 body plans possible
- Acoelomate
- Pseudocoelomate
- Schizocoelous coelomate
87
Deuterostome Mesoderm Formation
Mesoderm forms by an enterocoelous plan where cells from the central gut lining form pouches and expand into blastocoel
87
Triploblastic development
most common pathways are by spiral or radial cleavage
88
Radial Cleavage
- blastopore becomes the anus and new opening becomes the mouth
- coelom formation is by enterocoely
- cleavage is regulative
89
Spiral Cleavage
Produces embryos whose developmental pattern contrast with those of deuterostomes
- blastopore becomes mouth
- cleavage is mosaic
- may be acoelomate, pseudocoelomate, or coelomate via schizocoely
90
Ecdysozoan Protostomes
exhibit a range of cleavage patterns including spiral and superficial cleavage
can be coelomate or pseudocoelomate
91
Taxonomy
A formal system for naming and classifying species following the principle of common descent
92
Systematics
the broader science of classifying organisms based on studies of variation among populations that reveal their evolutionary relationships
93
Carolus Linnaeus
Designed the current system of classification
Sweedish botanist
94
Linnaean system of classification
Divided animal kingdom into species and gave each a distinctive name
Originally very limited
95
Binomial Species Nomenclature
Linnaeus's system for naming species is called binomial species nomenclature
two names, latin, universal
96
Common Descent
central theme to all modern concepts of species trace their ancestry to a common ancient population but not necessarily the same exact pair of parents
97
Smallest distinct groupings
species are the smallest unit sharing patterns of ancestry and descent
morphology has been traditionally used but now supplemented with chromosomal and molecular characteristics
98
Reproductive Community
species form reproductive groups that exclude other species
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Species Distribution
all species differ greatly in their distribution through space and time
- geographic range: cosmopolitan (species having very large geographic ranges or worldwide distributions), endemic (species with very restricted geographic distributions), range can either be continuous or disjunct
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Typological Species Concept
species was considered a distinct and immutable entity derived from divinely created patterns, new specimens were always compared to previously described representative specimen, large differences lead to description of new species
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