Lecture week 10 (10-26) - Notes Animal Diversity

Heterotrophic lifestyle

Deriving nutrition by consuming other life forms. Opposite from plants which are autotrophs.

Flexible cell membranes

Cell membranes that are flexible and not rigid like plant cells, that may or may not excrete extracellular matrix.

Extracellular Matrix (ECM)

A complex network of proteins and carbohydrates that surrounds cells and provides structural support.

Glycogen

A carbohydrate energy storage product created by all animals. Compare this to starch in plants.

Neuromuscular tissue

Tissue associated with movement and coordination of muscles.

Choanoflagellate protists

The closest living relative of animals.

Phylum Porifera (sponge)

The most ancient animal phylum with living representatives, such as sponges.

Ectoderm

The outer germ layer that gives rise to the skin and nervous system structures.

Endoderm

The inner germ layer that gives rise to the lining of the digestive tract.

Triploblastic

Three major germ layers

1. ectoderm

2. endoderm

3. mesoderm.

like humans.

Mesoderm

The middle germ layer that gives rise to muscles, bones, and most organ systems. Tissue

Asymmetry

The absence of symmetry, where the animal cannot be divided into equal halves such as sponges.

Radial Symmetry

Symmetry where many planes can divide the organism into equal halves through the center such as a starfish. No leading edge, they can move different ways

Bilateral Symmetry

Symmetry where only one plane can divide the animal into equal halves such as humans.

Body Cavity

A fluid-filled space that separates internal organs from the body wall. Space between the digestive tract and the outer body wall.

Acoelomate

Animals without a body cavity.

Pseudocoelomate

Animals with a body cavity that lacks a mesodermal lining of organs. These organs are exposed to the fluids of the body.

Eucoelomate

Animals with a body cavity and internal organs covered with a membrane derived from mesoderm. Organs surrounded by mesodermal lining used to protect those organs and keep them in place.

Embryology

The study of the development of embryos.

Protostomes

Animals in which the blastopore (ball of creation) becomes the mouth during embryonic development.

Deuterostomes

Animals in which the blastopore becomes the anus during embryonic development such as humans

Phylum Porifera

1. Asymmetrical

2. No germ layers

Sponges, benthic filter feeders with complex water canals throughout their bodies. Sponges are not our ancestors

Phylum Cnidaria

1. Radially symmetrical

2. Diploblasts

Animals containing cnidocyte cells, such as coral, anemones, and jellyfish, with radial symmetry, they’re diploblastic.

PLATYHELMINTHES (flatworms) - part of lophotrochozoans ( 1st protostome)

1. Triploblastic

2. Acoelomates

3. Bilateral symmetry

This phylum includes free-living flatworms and parasitic flukes and tapeworms. They have a flat body that maximizes surface area for diffusion of gasses and no respiratory system. They are bottom-dwelling scavengers with well-developed chemoreceptors for finding food. They grow by adding more body segments to the end of their body.

Phylum ANNELIDA (segmented worms) - part of lophotrochozoans

1. Triploblastic

2. Eucoelomates

3. Bilateral symmetry

This group includes earthworms, predatory marine worms, and leeches. They have a hydrostatic skeleton and gripping setae for burrowing. They have repetition of body parts along the body axis (segmentation) and play a role in nutrient cycling.

Phylum MOLLUSCA (chitons, snails, clams, squid, octopus, etc.) - part of lophotrochozoans

1. Bilateral symmetry

The mollusks are the second largest phylum and evolved from an annelid ancestor. They have a mantle, protective shell, muscular foot, and a scraping radula for feeding. Snails are the only ones that moved onto land.

Phylum NEMATODA (nematodes or roundworms) part of ecdysozoans

1. Bilateral symmetry

2. Pseudocoelomates

3. Triploblastic

Members of this phylum occur in most habitats and evolved from a flatworm ancestor. They have a protective cuticle that is shed for growth and play a role in nutrient cycling. They can tolerate extreme conditions and can cause diseases in animals.

Phylum ARTHROPODA (insects, crustaceans, spiders, etc.) part of ecdysozoans:

1. Protostomes

2. Bilateral symmetry

3. Triploblastic

4. Eucpelomates

These dominate in abundance and species diversity. They evolved from an annelid ancestor and have a chitinous exoskeleton that allows for movement on land. They have evolved a tracheae system and compound eyes.

Phylum ECHINODERMATA (starfish, sea urchins, sea cucumbers) part of deuterostomes:

1. Mixed symmetry

Echinoderms are slow-moving, omni-directional, heterotrophs with spines for protection. They have arms with gripping suction cups for locomotion and predation. They are the closest non-chordate relative to chordates. There’s always a star

Phylum CHORDATA (all with a notochord or more) part of deuterostomes::

Chordates are progressively more mobile, rigid-bodied heterotrophs. They have 4 key characteristics:notochord, pharyngeal gill slits, dorsal hollow nerve cord, and post-anal tail. There are 3 chordate subphyla:Urochordata, Cephalochordata, and Vertebrata. Where we are

What are the basic characteristics of an animal?

1. Heterotrophic lifestyle

2. Flexible cell membranes

3. Glycogen

4. Neuromuscular tissue

Germ layer

A collection of similarly produced cells.

Fundamental traits of animals groups

1. Germ layers

2. Body symmetry

No germ layers:

Think of “sponge,” it can rearrange itself after being cut through many times.

Diploblastic germ layer:

Two germ layers:

1. endoterm

2. ectoderm

Filter-feeding:

Primitive way of getting nutrients inside their bodies. In the case of sponges, choanocytes would move water creating a water current and then binding with the food.

How else can we divide triploblasts?

Body cavities

1. Acoclomate

2. Pseudoclomate

3. Eucoelomate

Classification of major animal groups - No germ layer:

1. Phylum Porifera - assymmetric

Classification of major animal groups - Diploblastic:

1. Phylum Cnidaria - radial symmetry

Classification of major animal groups - Lophotrochozoans:

1. Phylum Platyhelminthes - triploblastic, protostomes and bilateral symmetry

2. Phylum Annelida - triploblastic, protostomes and bilateral symmetry

3. Phylum Mollusca - triploblastic, protostomes and bilateral symmetry

No shedding to grow instead they show growing by incrementing additions to the body.

Classification of major animal groups - Ecdysozoana:

1. Phylum Nematoda - triploblastic, bilateral symmetry, and protostomes.

2. Phylum Arthropoda - triploblastic, bilateral symmetry, and protostomes.

Show growing by repeated shedding of the outer body exoskeleton

Classification of major animal groups - Deuterostomes:

1. Phylum Echinodermata - bilateral symmetry, triploblastic, and eucoelomate body cavities.

2. Phylum Chordata - bilateral symmetry, triploblastic, and eucoelomate body cavities.

What do lophotrochozoans and ecdysozoanas have in common?

They’re protostomes.

What are the major classes of vertebrate?

1. Chondrichthyes - sharks, rays

2. Osteichthyes - fish

3. Amphibia - frogs, tods

4. Reptilia - snakes

5. Aves - birds

6. Mammalia - us