Exam 4

Question 1

Echinoderm examples 5

Answer 1

Star fish, brittle stars, sea urchins, sand dollars, and sea cucumbers

Question 2

Echinoderm traits

Answer 2

Coelomates. Thin epidermis that covers a hard exoskeleton of calcareous plates. Water vascular system uses hydraulic canals to move water into tube feet for locomotion and feeding. NOT radial symmetrical, off-center, larvae are bilateral.

Question 3

Chordates timeline

Answer 3

Starting 530 MYA, around 365 some got limbs and moved onto land

Question 4

4 Chordate synapomorphies

Answer 4

Notochord (longitudinal, flexible rod between digestive tube and nerve cord). Dorsal, hollow nerve cord, above notocord. Phararyngeal slits. Musuclar, post-anal tail

Question 5

Cephalochordata

Answer 5

Lancelets. Basal group chordates. Feeds on plankton by drawing water over the pharyngeal slits.

Question 6

Urochordata

Answer 6

Tunicates. Filter feed with pharyngeal slits. Can squirt water out of their siphon so are commonly called sea squirts.

Question 7

Cyclostome

Answer 7

Lampreys and hagfish. No functional vertebrate.

Question 8

Lampreys (cyclostomes)

Answer 8

Larvae are suspension feeders. Some adults are parasites while others don’t feed and just reproduce. Also swim like a snake.

Question 9

Hagfish (cyclostome)

Answer 9

Highly reduced vertebrate and cartilage skull. Teeth made of keratin. Swim like a snake by pushing muscle against the notochorcd.

Question 10

Gnathostomes

Answer 10

Jaws! Includes sharks, fish, amphibians, reptiles, birds, and mammals. Jaws may have evolved from modifications to the skeletal rods supporting the anterior pharyngeal slits.

Question 11

Chondrichthyes

Answer 11

Sharks and rays. Skeleton of cartilage, but some vestigial traces of bone remain. Are predators are suspension feed on plankton.

Question 12

Chondrichthyes sensory system 5

Answer 12

Sharks have sharp vision, but are color-blind. Cup-like nostrils for olfaction. Ampullae of Lorenzini are electrical sensors in the head to sense muscle contractions in other animals. Uses inner ear to sense vibrations. Lateral line.

Question 13

Shark reproduction 3

Answer 13

Lots of variety. Oviparous: lay eggs that hatch outside the mother’s body. Ovoviviparous: retain the embryo in the oviduct with an embryo nourished by egg yolk, but comes out as a live birth. Viviparous: young development in the uterus and are born.

Question 14

Osteichthyes 5

Answer 14

(Ray-finned and lobe-finned fish). Bony endoskeleton with calcified bones. Breathe by passing water over 4-5 gills covered by the operculum. Swim bladder. Lateral line.

Question 15

Ray-finned fish (Osteichthyes)

Answer 15

27,000 species, 1/2 of all chordate diversity. Most familiar fish are in this group.

Question 16

Lobe-finned fish

Answer 16

Rod-shaped bones surround by thick muscles in the fins. May have used these to shuffle along the floor in shallow waters. Includes Coelacanths, Lungfish, and the Tetrapods

Question 17

Tetrapods 4

Answer 17

Limbs with digits. Life on land evolved a head separated by a neck, pelvic girdle connected to backbones, and conversion of the pharyngeal clefts into ear bones and other stuff.

Question 18

What fossil shows many transitions between fish and tetrapods?

Answer 18

Tiktaalik

Question 19

Amphibian (“both ways of life”) groups 3

Answer 19

Frogs, Salamanders, and Caecilians (legless/blind, look like earthworms).

Question 20

Amphibian characteristics 4

Answer 20

Many species live first in water, then on land. But some can be entirely water or land. Metamorphosis from tadpole to adult. Larvae have tails, gills, and no legs. Adults gain legs, lose the tail, and get lungs and eardrums. Most rely on skin for gas exchange so they need wet environments.

Question 21

Threats to amphibian diversity 2

Answer 21

Chytrid fungus and endocrine disruptors (Atrazine, pesticides)

Question 22

Amniotic eggs 5

Answer 22

Amniotic eggs prevent desiccation. The amnion protects the embryo in a fluid-filled cavity. The yolk sac contains a shit ton of nutrients. The Chorion and the allantois exchange gases. The allantois also disposes of waste.

Question 23

Reptile characteristics 3

Answer 23

Scales made of keratin. Lay pre-fertilized eggs on land. Ectothermic, a reptile uses only 10% of the energy as a similarly-sized mammal.

Question 24

Lepidosaurs (extant reptile group)

Answer 24

Tuataras (only 2 species in NZ), snakes, and lizards.

Question 25

Archosaurs

Answer 25

Turtles, crocs, and birds. The lower shell of a turtle evolved first, and the upper shell came later.

Question 26

Birds 5

Answer 26

Honeycombed bones. Exceptional color vision. Originated from bipedal theropod dinosaurs. Feathers may have evolved long before flight for other uses. Archaeopteryx had both reptilian and avian characteristics.

Question 27

Bird flight and intelligence

Answer 27

They are efficient hunters and scavengers and flight allows them to escape from predators. Flight lets them migrate to food resources and breeding opportunities.

Question 28

Mammal synapomorphies 6

Answer 28

Milk, hair, kidneys, endothermic, variation in teeth, and larger brains per body size.

Question 29

Groups of mammals 3

Answer 29

Montremes, marsupials, and eutherians

Question 30

Monotremes

Answer 30

5 species. Do not have nipples, the milk is sucked from the fur. Platypuses and echidnas.

Question 31

Marsupials

Answer 31

Give birth to live and underdeveloped young (hence the pouches, or marsupium).

Question 32

Marsupial and eutherian convergent evolution

Answer 32

Since Australia has been isolated for so long, marsupials took on ecological roles that eutherian animals have elsewhere. South America did have large marsupials, but they were wiped out when N and S America came into contact 3 MYA.

Question 33

Highlights of eutherian diversity 3

Answer 33

Numerous groups have returned to aquatic ecosystems. Mammals like bats have adapted for flight. Rodentia is the most species-rich mammal group with 30% of mammal diversity.

Question 34

Human evolution 3

Answer 34

We started evolving about 200k yrs ago. Fossils of many human-like ancestors have been found that have various intermediate characteristics. A newer hominid fossil is Homo luzonensis was found in 2019 and lived 50-67k yrs ago.