BIOL 1113 (General Biology 2) Final Exam Ana Otero

What are some common characteristics of Animals

Multicellular, Heterotrophs, No Cell walls, Similiar rRNA, presence of hox genes

What does the Hox Genes do?

Encode transcription factors which determine the course of embryonic development

When did Multicellular animals emerge?

They emerged at the end of the Proterozoic eon

What were the first animals

The first animals were invertebrates

What were the first vertebrate?

Fishes

Main characteristics of Invertebrates

• Without a backbone

• Make up 97-99% of all animals

• Heterogenous assemblage of groups

Main characteristics of Vertebrates

• Have a backbone

• 1% of animals

• Only 1 phylum

Metazoa= Animals

• Cells

• Tissues

• Epithelia: Joined cells on basal lamina, ciliated

• Connective Tissues: Separated cells + ground substance + fibers (collagen)

What are the levels of organization?

Cellular, Cell tissue, Tissue Organ, Organ System

Phylum example of the cellular level

Porifera—cells with specialized functions, no true tissues.

Phyla with cell-tissue level organization

Cnidaria and Ctenophora—cells form tissues but not true organs.

Phylum example of tissue-organ level organization

Platyhelminthes—tissues form organs with specialized functions.

Types of animals with organ-system level organization

Lophotrochozoa, Gnathifera, Ecdysozoa, Chordates, and more—organs form systems for body functions.

How animal life cycles begin

With meiosis forming sperm and egg, which fuse at fertilization to form a zygote.

Role of mitosis in animal development

Zygote divides by mitosis to form a multicellular embryo; all somatic cells retain the same chromosome number as the zygote.

Two main types of symmetry in animals

Radial (Radiata) and Bilateral (Bilateria).

Anatomical planes

Frontal (dorsal/ventral), Sagittal (left/right), and Transverse (anterior/posterior).

Oral/aboral axis

Describes the mouth (oral) side versus the opposite (aboral) side, especially in radial animals.

Germ layers

Embryonic cell layers that give rise to tissues and organs during development.

Coelom

A fluid-filled body cavity that houses organs and is derived from the blastocoel.

Types of body cavities in animals

Acoelomate (no coelom), pseudocoelomate (partial cavity), and eucoelomate (true coelom).

Advantages of having a coelom

Allows more space, increased surface area, organ storage, hydrostatic skeleton, and greater size/complexity.

Cleavage in embryonic development

The pattern of cell division during early development.

Cleavage in protostomes

Spital cleavage and determinate development.

Cleavage in deuterostomes

Radial cleavage and indeterminate development.

Parazoa

Subkingdom of Animalia; consists of one phylum: Porifera

Porifera

Only phylum of animals to have cellular level organization, aka no tissues; sacklike bodies with many ostia (pores); sessile filter feeders;

Ostia

Pores in the sponge body where water enters

Choanocyte

Specialized cell of sponge that functions to trap and eat small particles; cells have flagella that help

Spicules

Needle like structures of silica that make up the sponge "skeleton"

Osculum

Large opening at the top of a sponge where water exits

Archaeocytes

Amoeboid cells in sponges that can play in the role of sponge sexual reproduction

Mesohyl

Gelatinous, protein-rich matrix between the choanocytes and epithelial cells of a sponge.

Spongocoel

Large central cavity of sponges

Sessile filter feeder

Sponges are described as this because they are anchored in place and filter nutrients from their surrounding environment

(Sponge) sexual reporduction

One individual can produce both gametes

(Sponge) asexual reproduction

Porifera reproduction where a small fragment or bud detaches from a sponge and forms a new organism

gemmule

A special form of asexual reproduction which is only found in some and can survive harsh environments

Cnidaria

Radial Symmetry

Diploblastic
Tissue Level: ectoderm and endoderm

What are the two types of dimorphism?

Medusa and Polyp

polyp

Cnidarian body form that is sessile and occurs mouth up

medusa

Cnidarian body form that is motile and usually floats mouth down

gastrovascular cavity

Body cavity with single opening to the external environment where extracellular digestion takes place

Mouth + tentacles

• Mouth surrounded by tentacles with nematocyst

cnidocytes

Stinging cells that contain nematocysts which are stinging organelles

Nerve net

Interconnected neurons with no central control organ

Mesoglea

Gelatinous substance that connects the ectoderm/epidermis and endoderm/gastrodermis in Cnidaria; in jellyfish it is enlarged and forms a transparent jelly, in coral it is very thin

Where can epidermis be found (Cnidaria)

The epidermis can be found on the out layer, acting as protection

Where is the gastrovascular cavity found?

It’s found in the inner layer or gastrodermis

Do Cnidari have complete or incomplete digestive system?

They have an incomplete digestive system

How does the Cnidari digestive system operate?

Food is taken into the gastrovascular cavity and the cells lining the cavity absorb nutrients

With an incomplete digestive system what does that mean (Cnidari)?

The gastrovascular cavity acts as the mouth an anus

(three) classes of Cnidaria

Hydrozoa (hydras), Scyphozoa (jellyfish), Anthozoa (sea anemones and corals),

Jellyfish (Scyphozoa)- Life Cycle

Medusa→ Egg/Sperm→ Zygote → Larva→ Polyp→ Budding polyp→ Ephyra (repeat)

What dimorphism is dominant in jellyfish?

Medusa

What are the sense organs? (jellyfish)

Rhopalium

Hydrozoan

Class of cnidarians that form colonies of polyps enclosed by hard, chitinous covering; feeding polyps (gastrozooid) and reproductive (gonozooid)

Sea anemones (Anthozoa)

Class of cnidarians with life cycle of polyps, no medusa; large gastrovascular cavity divided by walls of septa; ciliated groove called siphonoglyph used to create currents of water into the pharynx; pedal laceration where pedal disk can regenerate entire new organism; acontia threads for defense

Corals (anthozoa) - zooxanthellae, calcareous cup, mutualism, reefs

Class of Cnidarians that live symbiotically with zooxanthellae, have polyps that sit on a calcareous cup, reefs

Hard Coral

Able to take many forms including boulder, branching, plate of cabbage like shapes

Soft Coral

Look more like underwater flowers and sway in the current

Coral Bleaching

Due to loss of zooxanthellae

How are Lophotrochozoan classified?

They are classified as lophophore (feeding apparatus) or trochophore (free-swimming)

Platyhelminthes/flatworms

Phylum of animals with organ-level organization, cephalization, bilateral symmetry, and ladder-type nervous system; acoelomate; triploblastic; majority are parasitic

excretory system (flame cell/protonephridia, tubules)

Flatworms have this type of body system that consists of protonephridia, two lateral canals with branches capped by flame cells, that are meant to maintain osmotic balance between the organism and its surroundings.

pharynx

Part of the throat that is behind the mouth where is food is drawn into; incomplete gut

Types of Platyhelminthes

Turbellarians (free-living), Trematodes (flukes), Cestodes (tapeworms)

Turbellarians

• Auricles= sense organs

• Muscle layers- Three kinds

  • Outer circular layer

  • Inner longitudinal layer

  • Diagonal layer

• Two light sensitive eye spots

• hermaphrodites- Have both male and female sex organs

flukes (trematoda)

Parasitic flatworms with well developed reproductive system; usually hermaphroditic; complex life cycle

What are the definitive and intermediate host of flukes

Definitive: Mammals; they are what the larvae penetrate first

Intermediate: Snails

tapeworms (cestoda)

Internally parasitic worms that use a variety of organs to attach to bodies such as hooks and suckers

cephalization

Development of a body suited for forward-directional movement and a head bearing sensory appendages

Flukes (trematoda)

Parasitic flatworms with well developed reproductive system; usually hermaphroditic; complex life cycle

Schistosoma

Blood fluke that causes disease caused by infection; correlated with human waste in water; caused by the blood fluke Schistosoma

Lophotrochozoa

clade of animals that produce trochophore larvae, which have two bands of cilia around their middle; byrozoa, brachiopoda, mollusca, annelida, platyhelminthes, and rotifera

Scolex (Tapeworm)

Attachment organ at the end of head that some flatworms use to latch onto their hosts

What are the bodies of tapeworms made of?

A long series of proglottids, each segment having a full set of male and female sex organs

Tapeworm Life Cycle

Primary host ingests meat that has bladder worms→ Bladder worm attaches to the intestine and matures into a tapeworm→ Tapeworm grows and fills with eggs→ Egg are released in the host’s feces, which may possibly contaminate water/vegetation→ Livestock may ingest eggs and become secondary host

Annelida

Phylum of animals known as segmented worms (metamerism), characterized as lophotrochozoans, eucoelomate, with protostome development and a closed circulatory system

Closed Circulatory System

Blood is always contained within vessels like arteries and veins while circulating throughout the body

Septa (Annelida)

Segmented partition that divide the coelom, acting as a hydrostatic skeleton

Chaetae (setae)- Annelida

Stiff bristles found in annelids to help in movement

parapodia (Annelida)

in annelids, paired muscular bristle-bearing appendages used in locomotion, respiration

What nervous system do Annelida have?

They have a ventral solid nerve cord

What are the 2 main classes of Annelida

Polychaetes (many bristles) and Oligochaetes (few bristles) which are earthworms and leeches

Polychaetes

Group of annelids with multiple chaetea per segment; have external fertilization and metamorphosis, and parapodia

Oligochaetes (Earthworms)

Annelids with no well developed head or parapodia; food drawn into mouth by muscular pharynx; hermaphroditic w/ cross fertilization, still reproduce sexually using clitellum; internal fertilization, no metamorphosis

What does the clitellum do?

It secretes mucus to protect sperm and the cocoon for desiccation

Leeches

• Found in fresh water

• 2 suckers

• produce hirudin, prevents blood clotting to keep blood flowing

Mollusca

Phylum of animals with three part body plan, often with a soft body protected by an external shell, reduced coelom, radula (feeding structure)

trochophore larva

Small free-swimming larva characteristic of marine annelids and mollusks; spherical or pear shaped, they are girdled by a ring of cilia that enables them to swim

Head-foot

Muscle adapted for locomotion, attachment, food capture, or sensory reception

Visceral mass

Structure in molluscs that sits on top of the foot and contains the internal organs

mantle

Fold of skin in molluscs that is draped over the visceral and secretes a shell and/or contributes to the development of gills or lungs

hemocoel

A form of open circulation; heart pumps hemolymph vessels into hemocoel

shell

Complex, three-layered structures that are secreted by the mantle of mollusks;

radula

a unique, protrusible, tonguelike organ that has many teeth and is used to eat plants, scrape food, or bore into shells of other species and tear flesh

Gills

Organs that are specialized for gas exchange in mollusks

open (circulatory system) - mollusca

Circulatory system with a heart that pumps body fluid called hemolymph through vessels and into open, fluid-filled cavities between internal organs

Gastropoda (univalves)

largest group of mollusks that includes snails, slugs, nudibranchs, etc.; most have one-piece shell (univalve) into which individuals can withdraw to and escape predators; well developed head