BI301 Final Exam

The Biological Species Concept

Two organisms are different species if they cannot or will not produce viable offspring together

Homologous traits

Traits that appear similar but serve a different function, evolved from a recent common ancestor

Analogous traits

Traits that serve the same function but may appear different in different organisms evolved due to similar selection pressures, not from a recent common ancestor

What are the two classes within Phylum Porifera

Demospongiae, hexactinellida, and calcarea

What are the defining features of Phylum Porifera?

1. Porous body (ostia)

2. Have choanocytes (specialised cells)

3. Lack symmetry, true tissues, organs, and nervous systems

4. Skeletons made of spicules, spongin, or calcium carbonate

What are the defining features of Phylum Porifera, Class Demospongiae?

1. Spongin skeletons

2. All leuconoid body type

3. Most have spongin skeletons

4. Tend to have chemical defenses

What kinds of specialised cells do organisms in Phylum Porifera have?

1. Choanocytes

2. Pinocytes

3. Amoebocytes

What are the defining features of Phylum Porifera, Class Hexactinellida?

1. 6-rayed spicules

2. “Glass sponges” with silica skeletons

3. Syconoid or leuconoid body type

What are the defining features of Phylum Porifera, Class Calcarea?

1. Calcium carbonate spicules

2. Smaller in size

3. All 3 body types present

What are the three body types of Phylum Porifera?

Asconoid, syconoid, and leuconoid

Cephalisation

The evolutionary trend of concentrating sense organs, nervous tissue (brain), and feeding mechanisms at the anterior (front) end of an animal, forming a head

What kind of body forms are found in Phylum Cnidaria?

Polyp and medusa

What are the defining features of Phylum Cnidaria?

1. Radial symmetry

2. Eumetazoan (true tissues)

3. Diploblastic (2 embryonic germ layers)

4. Ring nerves but lack of cephalisation

5. Statocysts and ocelli cells

What are the defining features of Phylum Cnidaria, Class Hydrozoa?

1. Alternate between polyp and medusa for reproduction but polyp stage dominates

2. Muscular velum during medusa stage

3. Mostly marine and colonial

What are the defining features of Phylum Cnidaria, Class Cubozoa?

1. Medusa-stage dominant

2. Cube shaped

3. Include cube jellies and sea wasps

What are the defining features of Phylum Cnidaria, Class Anthozoa?

1. NO medusa stage

2. All marine

3. Sea anemones and corals

What are the defining features of Phylum Cnidaria, Class Scyphozoa?

1. No true velum

2. Thick mesoglea

3. Dominated by the medusa form

What are some causes of coral bleaching?

• Cold shock

• Decrease in salinity

• UV exposure

• Increased water temperature

• Turbidity

• Pollution

• Sunscreen

What are the defining features of Phylum Platyhelminthes?

1. Lophotrochozoan

2. Acoelomate

3. Triploblastic

4. Polarised nervous system

What are the defining features of Phylum Platyhelminthes, Class Turbellaria?

1. Free-living

2. Mouth is ventral

3. Cilliated epidermis

What are the defining features of Phylum Platyhelminthes, Class Trematoda?

1. Parasitic flukes (endoparasites)

2. Multiple hosts during life cycle

3. Specialised suckers for attachment

What are the defining features of Phylum Platyhelminthes, Class Cestoda?

1. Parasitic tapeworms

2. Always have 2 hosts (1 invert. and 1 vert.)

3. Microtrix for nutrient absorption

4. Scolex for attachment

5. Proglottids for reproduction

What are the defining features of Phylum Nematoda?

1. Thick collagen cuticle

2. Hydrostatic skeleton

3. Only longitudinal muscles

4. Complete gut

5. Aflagellate sperm

Hydrostatic skeleton

A cavity filled with pressurised fluid that provides structural support and enables movement when muscles contract around it

What are the defining features of Phylum Annelida?

1. Metamerism

2. Chaetae

3. Peristaltic contractions

4. True coelom

What are the defining features of Phylum Annelida, Class Sedentaria?

1. Tube or burrow dwellers

2. Some have a clitellum

What are the defining features of Phylum Annelida, Class Errantia?

1. Parapodia for locomotion and respiration

2. No clitellum ever

3. Trochophore larva

What is the first major change in body plan on the phylogeny we talked about?

Parazoan vs. eumetazoan

Parazoan

Lacking true tissues

Eumetazoan

Having true tissues

What is the second major change in body plan on the phylogeny we talked about?

Radiata vs. bilateria

Radiata

Having radial symmetry

Bilateria

Having bilateral symmetry

What is the third major change in body plan on the phylogeny we talked about?

Protostomia vs. deuterostomia

What is the fourth major change in body plan on the phylogeny we talked about?

Only under protostomia, it is lophotrochozoan vs. ecdysozoan

Lophotrochozoa

Do not molt a cuticle

Ecdysozoa

Having a cuticle

What are the 4 (3.5?) ways protostomes differ from deuterostomes?

1. Cleavage pattern

2. Cell fate

3. Coelom formation

4. Blastophore fate

Deterministic cell fate

A cell’s function is completely predetermined and if a blastomere is somehow removed, development is arrested because the cell will no longer be able to do its job

Indeterminate cell fate

Like stem cells, a cell’s fate is not set in stone, so removing blastomeres will still lead to healthy cell development

What are the 4 classes of Phylum Mollusca?

1. Bivalvia

2. Gastropoda

3. Polyplacophora

4. Cephalopoda

What are the defining features of Phylum Mollusca, Class Bivalvia?

1. Divided in 2 halves

2. NO head

3. NO radula- they are filter feeders

4. Foot is a hydrostat

What are the definitive characteristics of Phylum Mollusca?

1. Muscular foot for locomotion and attachment

2. Mantle and cavity

3. Radula- rasping tongue

What are the definitive features of Phylum Mollusca, Class Gastropoda?

1. Operculum

2. Coiling and torsion

3. Eyes at tips of tentacles

What are the definitive features of Phylum Mollusca, Class Polyplacophora?

1. Flattened oval shape

2. 8 dorsal plates

3. Well-developed radula

4. Gills in mantle cavity

What are the defining characteristics of Phylum Mollusca, Class Cephalopoda?

1. Reduced or absent shell

2. Highly derived eyes

3. Jet propulsion

What are the benefits of having an exoskeleton?

• Protection → insoluble in water

• Prevent dessication

• Muscle attachment and movement

What are the 4 steps of ecdysis?

1. Pre-molt: old cuticle is digested away

2. Underlying endocuticle begins to grow

3. Old cuticle splits

4. New cuticle is inflated with air or water

What are the definitive characteristics of Phylum Arthropoda?

1. Ecdysis

2. First flight

3. Segmented with somites, which fuse to form tagmata

4. Exoskeleton

1. What are the defining characteristics of Phylum Arthropoda, Subphylum Trilobita?

1. Lack mandibles

2. Are extinct

What are the defining characteristics of Phylum Arthropoda, Subphylum Chelicerata?

1. Only have 2 tagmata

2. No mandibles

3. No antennae

What are the defining characteristics of Phylum Arthropoda, Subphylum Chelicerata, Class Arachnida?

1. Book lungs

2. Pumping stomach

3. Malphigian tubules

What are the defining characteristics of Phylum Arthropoda, Subphylum Myriapoda, Class Diplopoda?

1. Herbivorous

2. 2 pairs of walking legs per trunk segment

What are the defining characteristics of Phylum Arthropoda, Subphylum Myriapoda, Class Chilopoda?

1. Terrestrial carnivores

2. 1 pair of walking legs per trunk segment

What are the defining characteristics of Phylum Arthropoda, Subphylum Hexapoda, Class Insecta?

1. 3 tagmata

2. 3 pairs of uniramous appendages on the thorax

3. 2 pairs of wings

4. Diapause

5. Metamorphosis

What are the defining characteristics of Phylum Arthropoda, Subphylum Crustacea?

1. 2 pairs of antennae

2. Carapace

3. Swimmerets

What are the defining characteristics of Phylum Echinodermata?

1. No ability to osmoregulate

2. Pentaramous symmetry as adults, bilateral as larvae

3. Calcareous endoskeleton

4. Water vascular system

What are the defining characteristics of Phylum Echinodermata, Class Ophiuroidea?

1. No pedicellarie

2. No anus, madreporite on oral surface instead

3. 5 movable jaw-like plates

4. No suckers on tube feet

5. Bursae

What are the defining characteristics of Phylum Echinodermata, Class Echinoidea?

1. Dermal ossicles make up endoskeleton

2. Herbivorous

3. No arms

4. ARISTOTLES LANTERN

What are the defining characteristics of Phylum Echinodermata, Class Holothuroidea?

1. Soft, leathery bodies

2. Secondarily bilateral

3. Oral tentacles

4. Respiratory tree

What are the defining characteristics of Phylum Echinodermata, Class Crinoidea?

1. Leathery body disc

2. Flexible, branched arms

Osmoregulation

The physical ability to maintain a stable water balance in the body

Water vascular system

Hydraulic network in echinoderms made up of canals and tube feet that functions for locomotion, feeding, respiration, and sensory processing

What are the 5 defining characteristics of Phylum Chordata?

1. Notochord

2. Dorsal, hollow nerve chord

3. Muscular post-anal tail

4. Endostyle/thyroid gland

5. Pharyngeal pouch or slits

What are the defining characteristics of Phylum Chordata, Subphylum Urochordata?

1. Marine

2. Sessile

3. Non-living tunic that surrounds the body

What are the defining characteristics of Phylum Chordata, Subphylum Cephalochordata?

1. Filter feeders

2. Segmented muscles

3. Closed circulatory system lacking a heart

What are the defining characteristics of Phylum Chordata, Subphylum Vertebrata?

1. A CRANIUM

2. Vertebral column in some

What are the defining characteristics of Phylum Chordata, Subphylum Vertebrata, Class Chondrichtheyes?

1. Secondarily cartilaginous skeleton

2. Carnivorous

3. Placoid scales

4. Lack a swim bladder

5. Lateral line system

6. Spiracle

What are the defining characteristics of Phylum Chordata, Subphylum Vertebrata, Class Actinopterygii?

1. Ossified calcareous skeleton

2. Operculum covers gills

3. Swim bladder

4. Complex osmoregulation

What are the defining characteristics of Phylum Chordata, Subphylum Vertebrata, Class Amphibia?

1. Ectotherms

2. No scales, moist skin

What are the defining characteristics of Phylum Chordata, Subphylum Vertebrata, Class Reptilia?

1. Waterproof skin

2. Negative pressure respiration

3. Amniotic egg