BIOL 205 (1/14) Introduction

functional morphology

Functional reasons behind the structure of an organism

Ontogeny

The history of development of an individual organism during its lifetime.

Phylogeny

The evolutionary history of a species or group of related species

What is an animal?

An organism that.....

1. Eukaryote

2. Multicellular

3. Internally Digestive Heterotroph

4. Locomotor Ability

5. Sense Organs & Rapid Responses

6. Sexual Reproduction (Diploid Life Cycles)

7. Fundamental Levels of Biological Organization

What are the Fundamental Levels of Biological Organization

- Sub-atomic (Quantum)

- Molecules

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- Organelles

- Cells

- Tissues

- Organs

- Organ Systems

- Organisms

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- Populations

- Communities

- Ecosystems

- Biomes

- Biosphere

Types of body symmetry

1. Asymmetrical

2. Radial

3. Bilateral

Geometric (Bi-lateral) Symmetries of Organisms

- Anterior/Posterior (Transverse (Cross) Section)

- Ventral/Dorsal (Belly/Back)

- Mid-Sagital Section (Left/Right)

Embryonic Germ Layers

1. None

2. Diploblastic

A) Ectoderm

B) Endoderm (Entoderm)

3. Triploblastic

A) Ectoderm

B) Mesoderm

C) Endoderm (Entoderm)

True Tissue

A group of interconnected cells completing a certain function

- Basal Lamina /Basement Membrane

basement membrane (basal lamina)

thin layer of connective tissue underlying the epithelium of many organs

Epithelium

the specialized epithelial tissue that forms the epidermis of the skin and the surface layer of mucous membranes

Ectoderm

Outer Skin

Mesoderm

middle germ layer; develops into muscles, and much of the circulatory, reproductive, and excretory systems. Includes coelomic spaces and complex management of muscles

Lumen

space within a tubular part or organ, such as the space within a blood vessel

Mesenchyme

The tissue from which almost all connective tissues are formed.

Thick jelly-like matrix with living cells + structural Elements

Endoderm/ Gut Epithelium/ Gastrodermis

innermost germ layer; develops into the linings of the digestive tract and much of the respiratory system.

Peritoneum

- Double-layered membrane surrounding the abdominal organs.

- Mesodermlly derived tissue completely enveloping the coelom.

(You can't have a coelom without a peritoneum)

Double Peritoneum

Has a mesentery

mesentery

a fused double layer of the parietal peritoneum that attaches parts of the intestine to the interior abdominal wall. Has nerves which can pass through it, connecting the body to the gut

Blastocoelom

Body cavity not completely lined by mesoderm. Usually a fluid filled space which is NOT defined by the peritoneum

Acoeolomate

An organism with no body cavity/ fluid filled spaces devoid of muscles

True Coelomate

An animal that possesses a body cavity lined by tissue completely derived from mesoderm. Pushing living cells towards gut which causes it to increase in size by building a robust core usually via seawater. The seawater acts as an incompressible fluid and creates structural integrity for the organism.

Blastocoelomate

Animals that DO NOT have a coelom. They have a a fluid filled body cavity, not derived from mesoderm, not enclosed with peritoneum. They are also usually super flat with hyper-optimized surface area for maximal nutrient intake & optimal respiration/gas exchange.

phylogenetics

the study of evolutionary relationships among species

phylogenetic tree

a hypothesis of the evolutionary relationships among different

organisms. These hypotheses are based upon shared morphological, behavioral, biochemical, and genetic characters

Cladistics

study and classification of species based on evolutionary relationships

4 types of classifications

I. Storage & retrieval system

II. Communication

III. Reflect evolutionary relationships

VI. Taxa vs. ranks

Taxa/Taxon

A taxon (plural: taxa) is a named group of organisms. For example, the species Homo sapiens is a taxon, the Phylum Mollusca is a taxon, and the Class Hexactinellida is a taxon.

Convergence

(convergent evolution), meaning that these taxa each evolved this character state independently during different evolutionary events, as opposed to having inherited this character state from a common ancestor.

How do we classify character states?

We can classify character states as being either ancestral (plesiomorphic) or derived (apomorphic). On a phylogenetic tree, we may indicate the specific point in time at which a new character state evolved - this is the approximate point in time at which this

character changed from the ancestral state to the derived state.

Phenotypic Character

A phenotypic character is a feature of an organism that can be observed, such as eye colour or jointed appendages

Parsimony

Simplest explanation (Path of least steps)

Types of Cladograms

monophyletic, paraphyletic, polyphyletic

Cladogram

Diagram that shows the evolutionary relationships among a group of organisms

Monophyletic group

Group that contains one complete evolutionary history (Ancestor + all of its descendants).

Also called a Clade

What are the two types of homologies?

Synapomorphies & Symplesiomorphies

Homologies

Any trait in two or more lineages that was present in the most common ancestor

E.g) hair in humans & dogs

Polyphyletic group

Phyletic group excludes common ancestor

Paraphyletic group

Incomplete/Partial.

Ancestor + Some descendants

Synapomorphy

shared derived trait/character, a synapomorphy is a homologous character.

Symplesiomorphy

shared ancestral trait/character, a symplesiomorphy is a homologous character.

Outgroup

a taxon of organisms that is closely related to, but not part of, the ingroup.

Digestive Tract

a hollow digestive space surrounded by body tissues. It must open to

the environment to allow food to enter and undigested matter and wastes to exit.

Complete Digestive Tract

Some organisms, like humans, have two separate openings to the digestive tract: a mouth for ingestion of food and an anus for voiding of feces. This is called a complete digestive tract.

Incomplete Digestive Tract

Only one opening to the digestive tract; this same opening

is used both for ingestion of food and for voiding of feces. This is called an incomplete digestive tract, or gastrovascular cavity (GVC)

Hearts

Specialized muscular pumps for moving blood through the circulatory system.

Animals with a specialized circulatory system (either open or closed) usually have some form of muscular pump.

Jointed Appendages:

Appendages are outgrowths of the body (legs or antennae, for

example). In animals with jointed appendages, only certain regions of each appendage are flexible (these clearly defined flexible regions are the joints), while the rest of the appendage is inflexible.

Animals without jointed appendages will either have no

appendages at all, or if they do have appendages, the appendages will be flexible along their entire length (no inflexible regions) or will be completely inflexible along their entire length.

cerebral ganglion (brain)

a mass of neuron cell bodies located in the anterior region

of an animal, from which one or several longitudinal nerve cord(s) emerge.

Morphostasis

Traits staying the same.

Phenotypic Character

A feature of an organism that can be observed, such as eye colour or jointed appendages.

Character state

The observed condition of a character, such as presence or absence of lungs or arrangement of petals.

Morphological Characters

Anatomical structures such as a muscle or a gill.

Developmental characters

characters that are typically used in distinguishing protostomes from deuterostomes, such as changes in growth rate, weight, and symmetry.

Behavioral Characteristics

behaviors or movements the animal displays that are related to how the animal responds to its environment (movement, actions, interactions).

Physiological characteristics

the functioning of organ systems within the body

Biochemical characteristics

presence of particular enzymes or sets of enzymes

Homologous characters

Shared characters that were inherited from a common ancestor

Shared character

When two or more taxa have the same character state for a character.

Fore example, if structure X in one species and structure Y in a different species both arose from the same structure in the common ancestor of these two species, then we can say that structure X and structure Y are homologous.

Convergence (Convergent Evolution)

Evolution of similar features independently in different evolutionary lineages, usually from different antecedent features or by different developmental pathways.

Ancestral character states (Plesiomorphic)

a character state that was present in the most recent common ancestor of the entire taxon

derived character states (apomorphic)

Character states arise within a taxon of interest after diverging from a common ancestor.

Synapomorphy

An apomorphy (derived character state) that is shared by two or more taxa and their most recent common ancestor, which is also referred to as a shared derived character state for those taxa.

By definition it is a homologous character

Symplesiomorphy

A plesiomorphy (ancestral character state) that is shared by two or more taxa.

By definition, it is a homologous character.

Outgroup

The taxon of organisms that is closely related to, but not part of, the in ingroup

Ingroup

Symmetry

The arrangement of an object/body structures in relation to the axes of that respective object/body