Week #4 - Animal Kingdom Flashcards
Describe the distinguishing characteristics of animals.
- they are multicellular eukaryotes, and are heterotrophic through ingestion
- cells lack a cell wall
- body is connected by structural proteins such as collagen
- nerve and muscle tissue (possessed by animals but not all)
Outline an hypothesis for the origin of animals from ancient animal-like protists.
Land animals were said to have evolved from the animal-like protist, choanoflagellate, approximately 700 million years ago. The cambrian explosion 530 million years ago marked the appearance of many diverse marine animal species. It wasn’t until 70 million years later that animals started to migrate onto land and later on develop vertebrae for body support.
Define coelom and identify which phyla possesses this feature.
A coelom is a fluid-filled cavity that is completely covered by a mesoderm tissue. Phyla that possess this feature are the annelida, chordata, echinodermata, mollusca, and arthropoda.
Distinguish between radial and bilateral symmetry and provide examples.
Radially symmetric animals are animals that can be separated into identical halves on any plane whereas bilaterally symmetric animals can only be separated into identical halves on one plane. An example of a radially symmetric animal is a jellyfish and an example of a bilaterally symmetric animal is a tiger.
Distinguish between endoskeleton and exoskeleton.
An endoskeleton is a supportive structure that develops within an animal. It is made up of two types of tissue: bone and cartilage. Whereas an exoskeleton is a supportive structure that is found on the exterior of an animal. It also functions to protect the soft tissues of certain animals.
Distringuish between extra cellular and intracellular digestion.
Extracellular digestion takes place outside of the cell, usually in compartments of an animals body whereas intracellular digestion takes place within the cell. Food particles are engulfed through endocytosis and broken down by hydrolytic enzymes found in the cells’ vacoules.
Define ingestion
ingestion is the process by which an animal engulfs food particles into its body or digestive system.
Define digestion
digestion is the breakdown of food particles inside an animal. It must first go through mechanical digestion, where food is broken down into smaller pieces. It is then broken down further in chemical digestion where enzymes break apart chemical bonds of large molecules so that it can be absorbed into the body’s cells.
Define absorption
absorption is the uptake of organic compounds and nutrients after food particles have been broken down into small, absorbable molecules.
Define elimination
elimination is the removal of undigested material from an animals’ digestive system.
Define tissue
a group of many similar cells (though sometimes composed of a few related types) that work together to perform a specific function.
Define organ
an anatomically distinct structure of the body composed of two or more tissue types. Each organ performs one or more specific physiological functions.
Define organ systems
a group of organs that work together to perform major functions or meet physiological needs of the body.
Major characteristics of Porifera
- unique feeding system. They possess tiny pores in their outer walls through which water is drawn. cells in the sponges’ walls filter necessary compounds from the water and pumps out the water through the osculum.
- acoelomates and diploblastic (pinacoderm and choanoderm)
- endoskeleton either calcareous spicules (calcium carbonate), siliceous spicules (silica), or sponging fibers (protein)
- sessile and are fixed to one place
Major characteristics of Platyhelminthes
- body is dorsoventrally flattened
- some are free-living but most are parasitic
- acoelomates
- triploblastic
- soft bodied organisms with no segmentation
