Animals

Question 1

Metabolism

Answer 1

Heterotrophs that use oxygen for aerobic respiration –> feed on plants, fungi, and each other (some have symbiotic relationships with autotrophs to get food)

Question 2

Development/Phylogeny

Answer 2

1. Start from common ancestor: colonial, flagellated protist
2. Nerve development
3. Radial symmetry vs bilateral symmetry
4. Bilateral divided into protostomes and deuterostomes based on embryonic development
5. Deuterostomes broken down into invertebrates (echinoderms) and vertebrates (chordates)

Question 3

Start of Animal Kingdom

Answer 3

Common ancestor to all animals was likely a colonial, flagellated protist that lived at least 700 million years ago –> likely formed from colony of cells that became indented, forming a hollow cavity for food

Question 4

Nerves

Answer 4

Developed nerves after evolution of common ancestor

Question 5

Symmetry

Answer 5

Radial Symmetry: body arranged around a central axis
Bilateral Symmetry: body has a left and right side that mirror each other –> has front (anterior), back (posterior), upper (dorsal), lower (ventral) surfaces

Question 6

Division of Bilaterally Symmetrical

Answer 6

Bilaterally symmetrical animals divided into two groups based on embryonic development:
Protostomes: mouth forms before anus –> 6 major phyla, vast majority of animal species, all invertebrates
Deuterostomes: anus forms before mouth –> 2 phyla

Question 7

Division of Deuterostomes

Answer 7

Deuterostomes broken down into:
Echinoderms: invertebrates (no backbone)
Chordates: vertebrates (have notochord = backbone)

Question 8

Echinoderms

Answer 8

Invertebrates, mature to form a radially symmetrical pattern (ex. sea stars)

Question 9

Chordates

Answer 9

Vertebrates –> primitive chordate was bilaterally symmetrical with gill slits, dorsal nerve cord, and notochord; internal supporting skeleton helped them develop large body size and waterproof amniotic egg, resistant to water loss, allowed some to conquer land (ex. fish, birds, amphibians, reptiles, mammals, humans)

Question 10

Phylum

Answer 10

Porifera: sea sponges (no nerves)
Cnidaria: jellyfish (radially symmetrical, nerves)
Platyhelminthes: tapeworms, Rotifera: zooplankton, Mollusca: snails, Annelida: earthworms, Nematoda: tapeworms, Arthropods: crustaceans & insects (protostomes, bilaterally symmetrical, nerves)
Echinoderms: sea stars, Chordates: humans (deuterostomes, bilaterally symmetrical, nerves)

Question 11

Vertebrate Success Story

Answer 11

• Enlarged & protected brain, eyes, ears, and noses provided vertebrates with enhanced sensory capabilities
• Limbs, protective outer skin, enhanced lungs & circulatory system, internal fertilization, and eggs with outer shells all allowed them to conquer land