Animals Flashcards
(41 cards)
Common Characteristics of Animals
- multicellular
- Heterotrophs
- No cell walls: flexibility
- Nervous tissues: rapid response
- Muscle tissue: movement
- Sexual reproduction
- Extracellular matrix: collagen
- similar rRNA
Characteristic cell junctions: anchoring, tight, gap
When did multicellular animals emerge?
- Multicellular animals emerged end of Proterozoic eon
first animals were…
invertebrates
Three possible explanations for sudden increase in animal diversity during Cambrian explosion…
1) Favorable environment: warm temp, increase in atmospheric/aquatic oxygen, ozone layer developed
2) Evolution of Hox gene complex
3) evolutionary arms race
Hox Gene Complex
a group of related genes that specify regions of the body plan of an embryo along the head-tail axis of animals
Evolutionary arms race
an evolutionary arms race is an ongoing struggle between competing sets of co-evolving genes, phenotypic and behavioral traits that develop escalating adaptations and counter-adaptations against each other, resembling the geopolitical concept of an arms race.
1st vertebrates are…
Fish 1st vertebrates, plants colonized around same time and provided a food source for animals
Challenges of life on land…
- animals developed lungs, internal fertilization, amniotic egg
What dominated earth for millions of years? what did the extinct of dinosaurs allow for?
Reptiles dominated Earth for millions of years, the dinosaurs died 65 million years ago giving way to explosion in mammal number and diversity
Animals - 2 Major Categories: Invertebrates
- no backbone
- makes up 97-99 % of animals
- Heterogeneous
- No single positive character in common
ex. sponges, jellyfish, worms, insects, clams, snails, sea stars
Animals - 2 Major Categories: Vertebrates
- backbone
- 1% of animals
- 1 phylum
ex. fish, frogs, birds, reptiles, mammals, humans
Bauplan
Basic design of each major taxonomic group; starting point
Established Evolutionary Relationships
framework to organize and compare bauplans
Function principles
physical, chemical, biological, physiological, development, ecology
Body design determined by:
- type of environment
- size of animals
- mode of existence
- constraints of genome (ancestral design)
Metazoa
all animals having the body composed of cells differentiated into tissues and organs and usually a digestive cavity lined with specialized cells.
Cellular Level: Porifera
- Aggregations of cells, groups with specialized functions
- Division of labor
Cell-tissue Level: Cnidaria, Ctenophora
- groups of similar cells arranged in definite patterns or layers with a common function = tissue
- many scattered cells still present
Tissue-organ Level: Platyhelminthes
- Tissues arranged into organs
- organs consist of multiple tissue types and has a very specialized function
Organ-system Level: Everyone else (Lophotrochozoa, Gnathifera, Ecdysozoa, Chordates)
- groups of organs working together to preform a particular function
- systems associated
- 11 body systems: Integumentary, Nervous, Urinary, Skeletal, Digestive, Circulatory, Endocrine, Muscular, Respiratory, Immune & Reproductive
Body systems: Integumentary
protection, respiration, nutrient uptake coloration, temp. regulation
Body systems: Muscular
movement
Body systems: Skeletal
Support, leverage, storage
Body systems: Nervous
reception of information, analysis. coordination of response
