Intro to Animals

10 views3 pages

For unlimited access to Class Notes, a Class+ subscription is required.

Intro to animals
Characteristics of animals:
1) Eukaryotic true nucleus
2) Heterotrophic (different feeding):
- using pre-formed organic materials as energy and carbon source
- predators (tiger), herbivores (cow), filter feeders (fan worm), parasites
(tape worm), detritovores (earth worm), omnivores
- Most have internal digestion:
- Most use internal processes to break down food (unlike fungi)
- Most have a gut continuous with the outside environment =
internal digestion
3) Multicellularity:
- specialized cells for specific functions
- allows organisms to grow larger small cells = bigger SA Volume ratio
-facilitate diffusion, increases efficiency of transport across the cell
membrane and within the cell
4) No cell walls
Support? = Skeletons
- hydostatic skeleton: muscle contract against fluid-filled cavity
- exoskeleton (external): non living cover that doesn’t grow, must molt.
hardening of new shell leaves animals vulnerable
-Ecdysozoans = molting animals
-Endoskeleton (internal): living tissue in vertebrates, non-living tissue
carbonate) in invertebrates
5) Motility at some life stage:
- movement reduces competition for resources and enhances genetic
diversity (move away from parents to mate with more separate organisms)
6) Somatic body cells are diploid (2N)
-Germ cells are haploid and come together to make a diploid zygote
7) Animals are diplontic
-as opposed to alternation of generation and haplontic life cycle
(8) Most animals have tissues = groups of similar cells organized into a functional
(muscular, nervous, connective, epithelial)
-Tissues come together = organs for more complex tasks
Animal diversity and origins:
-35 phyla
-1 million classified species
- 97% are invertebrates
- monophyletic (one common ancestor)
- similar gene sequences unique to animals (hox genes act in
development and control specialization of stem cells)
Unlock document

This preview shows page 1 of the document.
Unlock all 3 pages and 3 million more documents.

Already have an account? Log in

Get access

$10 USD/m
Billed $120 USD annually
Homework Help
Class Notes
Textbook Notes
40 Verified Answers
Study Guides
1 Booster Class
$8 USD/m
Billed $96 USD annually
Homework Help
Class Notes
Textbook Notes
30 Verified Answers
Study Guides
1 Booster Class