Bio 120 Exam 3 Vocab

What are the characteristics of animals?

1. Eukaryotic

2. Heterotrophic

3. Multicellular

4. Diverse

Asymmetry

• Lack of symmetry

• Porifera (sponges)

Radial Symmetry

• Arrangement around a central axis

• Cnidarians, ctenophores

• Oral (side of the mouth)

• Aboral (away from the mouth)

Bilateral Symmetry

• Divides body along a sagittal plane (right and left halves)

• Allows cephalization (anterior vs. posterior.)

• All other animals

Parazoa

• “Beside” animals

• No true tissues or symmetry

• Sponges (Porifera)

Eumetazoa

• All other animals who have distinct tissues & symmetry

Radiata

• Diploblasts

• Two germ layers

  • Ectoderm & endoderm

• Radial symmetry

Bilaterata

• Triploblasts

• Three germ layers

  • Ectoderm, mesoderm, and endoderm

• Bilateral symmetry

Diploblast & Triploblast diagram

Endoderm

Inner lining of most digestive tract organs, trachea and lungs

Mesoderm

All muscle, bone, cartilage, blood and most other visceral organs

Ectoderm

Outer epithelium of body surface, CNS

Multicellularity

A living thing composed of more than once cell and typically more than one cell type that work together to perform life functions.

Heterotrophy

An organism that cannot manufacture it’s own food and must obtain organic carbon, energy, and nutrients by consuming other plants, animals or organic matter.

Acoelomates

• Lack of a body cavity

• Mesodermal is filled with tissue

• Platyhelminthes (flatworms)

Pseudocoelomates

• False body cavity

• Derived from both endoderm and mesoderm

• Still functional - hydrostatic skeleton

• Nematodes (roundworms)

Eucoelomates

• Within mesoderm

• Body cavity & internal organs lined w mesoderm

• Holds organs in place

• Most other animals

Acoelomate, pseudocoelomate, eucoelomate diagram

Protosomes

Blastopore becomes the mouth, anus is the second opening

Deuterostomes

Blastopore becomes anus, mouth forms from second opening

Protostomes and Deuterostomes diagram

Gastrulation

• Forms gastrula

• Invagination forms Blastopore and archenteron (embryonic gut)

• Sets up formation of outer and inner germ layers (mesoderm also forms)

Animal Reproduction and Development diagram

Protostomes - cleavage patters

• Spiral cleavage

  • Angled cleavage, leads to spiral patterns along embryo axis

• Determinate cleavage

  • Fate of cells is determined early

Choanoflagellate

• Eumetazoa and parazoa likely evolved from a common ancestor that resembled choanoflagellate

Ediacaran period

• 543-635 million years ago

• famous for marking the first widespread appearance of large, complex, soft-bodied multicellular life

• Biota likely evolved from protists

Hox genes

A group of master regulatory genes that determine the basic head-to-tail (anterior & posterior) body plan and segment identity of developing animal embryos.

Benthic sessile

Any aquatic life-form that lives on, in, or attached to the bottom of a body of water and remains permanently fixed in one place as an adult

Benthic motile

A creature or micro-organism that lives on, in, or near the bottom substrate (the benthos) of an aquatic environment such as an ocean, lake, or stream and has the ability to move around

Intracellular digestion

The breakdown of complex food particles or cellular debris directly inside the cytoplasm of a cell

Sponges diagram

Cnidaria phylum

• Class Hydrozoa

• Class Scyphozoa

• Class Cubozoa

• Class Anthozoa

Cnidaria diagram

Platyhelminthes diagram

Pharynx

The throat

Ventral nerve cords

A major central nervous system structure in invertebrates that functions as the physiological equivalent of the vertebrate spinal cord.

Nematoda diagram

Phylum Mollusca

• Class Polyplacophora

• Class Gastropoda

• Class Bivalvia

• Class Cephalopoda

Ganglia

Collection or cluster of neuron cell bodies located outside the CNS in the peripheral nervous system.

Ocelli

Simple, light-detecting organs found in insects, spiders, and various other invertebrates.

Mantle cavity

A central anatomical space in mollusks and brachiopods formed between the main body and the surrounding fold of tissue called the mantle.

Mollusc Anatomy diagram

Feeding Types

• Grazers

  • Radula - scraping tongue

• Filter feeding

• Egg eaters

• Active predation

Gastrulation Diagram

Who are humans’ closest relatives?

Vertebrates

Chordate diagram

What is the notochord?

A flexible rod-like structure in chordates that provides support and is present during the embryonic stage. It eventually develops into the vertebral column in vertebrates.

What is the dorsal hollow nerve cord?

A tubular structure in chordates located above the notochord that develops into the central nervous system, consisting of the brain and spinal cord.

What are pharygeal gill slits?

Structures found in the pharyngeal region of chordate embryos that develop into gills in aquatic species or contribute to other structures in land vertebrates.

What paedogenesis?

The occurrence of reproductive maturity in larval forms, allowing them to reproduce before undergoing metamorphosis into adult forms.