Lecture 17

Question 1

Vertebrates

Answer 1

Development of a skeletal system and more complex nervous system - better ability to chase pray and run from predator

Question 2

Most vertebrates have vertebrate that

Answer 2

enclose the spinal cord - replaces the mechanical roles of the notochord

Question 3

Early diverged vertebra

Answer 3

No jaws, cartilage skeleton composed of extracellular matrix proteins like collagen
Cartilage can be mineralized with calcium for added support

Question 4

Gnathostomes “jaw mouth”

Answer 4

Jaws: Hinged structures that enable animals to grip food items/slice them
cartilage fish (sharks, rays)
- One of the biggest and most successful vertebrate predators in the ocean
Predominantly cartilage skeleton

Question 5

Limited use of mineralization for gnathostomes may be a

Answer 5

derived trait for these species as mineralization was present before they diverged from other vertebrates

Question 6

Ray finned fishes and lobe finned fishes

Answer 6

Nearly all have ossified (bony) endoskeleton with a hard matrix of calcium phosphate

Question 7

Ray finned fishes

Answer 7

• fins are made of bony rays connected with webs without muscular structure
• most of the extant fish species are ray finned

Question 8

Lobe fin fishes

Answer 8

• Pectoral and pelvic fins have a thick muscle supporting the bony fin
• Muscular fins can be used to walk on the bottom of the water
• Not a lot of extant species (with exception)

Question 9

3 major groups of lobe fin fishes

Answer 9

coelacanths: The living fossil that is believed to have remain unchanged from its ancestral shape for 400 million years

Lung fish: fish who has lungs as the means for gas exchange (in addition to gills)

Tetrapods: Sister group of lung fish who adapted to life on land
- muscular, pectoral and pelvic fins of lobe fin fishes evolved into limbs with digits

Question 10

tetrapods

Answer 10

are gnathostomes that have limbs with digits
- diverged 365 million years ago
Limbs support animal’s weight on land while digits efficiently transmit forces to the ground when walking
Limbs changing into hands, wings and flippers

Question 11

Amphibias

Answer 11

Salamanders, frogs
Amphibian refers to the dual life stages of frogs:
Tadpole: Aquatic larval stage, herbivore, legless, tail, gills
Frog: terrestrial adult stage, carnivore, legs, tailless, lungs

Question 12

Many amphibians are strictly

Answer 12

aquatic or terrestrial
- still need to inhabit moist habitat
- Major gas exchange through skin
- Lays egg in moist environment or in water: eggs are not well protected from desiccation

Question 13

Amniotes

Answer 13

Are tetrapods with terrestrially adapted eggs
- reptiles and mammals

Question 14

Amniotic eggs contain

Answer 14

specialized membranes to nurture the embryo
- Amnion is the membrane that encloses the amniotic fluid which the embryo floats in
- Other membranes function in gas exchange, transfer of nutrients, waste storage

Question 15

Amniotic eggs allow

Answer 15

terrestrial organisms to nurture embryo without having access to a body of water

Question 16

Allatonois and chorion

Answer 16

Amniotic sac for waste disposal
Chorion: gas exhange

Question 17

Many amniotic eggs have

Answer 17

a shell, others lack a hard shell and develop inside the parent’s body

Question 18

Reptiles

Answer 18

Turtles, lizards, snakes
Many reptiles such as lizards are ectothermic
“cold blooded”
Use the environment (sun/shade) to regulate their body temperature

Birds
- endothermic
- Use metabolic activity to maintain body temp
- Less energy efficient but resilient to harsher environments

Question 19

Mammals

Answer 19

Amniotes that have hair and produce milk to nurture the young

Mammals are endothermic with high metabolic rate
- hair and fat layer under skin provides insulation

Have a larger brain for body size
- allows complex learning behaviour such as offspring learning skills from parents

Question 20

Milk

Answer 20

balanced diet rich in fats, sugars, proteins, minerals and vitamins
- produced in mammary glands

Question 21

Monotremes

Answer 21

found only in austria and new guinea
- platypus and echidnas
- lays eggs was with other non mammalian amniotes

Question 22

three mammalian types

Answer 22

monotremes, marsupials, eutherians (placental mammals)

Question 23

Marsupials

Answer 23

Kangaroos, koalas
Embryo develops inside the female body, nurtured by the placenta
Child born very early in development and gets nourished in the mother’s pouch

Question 24

Most extant marsupials are in the

Answer 24

Australian region
- opossum are the few marsupial species that still survive in north/central america
Convergent evolution may have given rise to many marsupials which look similar to placentals that occupy similar ecological niches

Question 25

Eutherians (placental mammals)

Answer 25

Have placenta that are more complex than marsupials - longer pregnancy - young eutherians complete their embryonic development within the uterus Various life forms and habitats - wide range of food, meat, insects Teeth of mammals bear a variety of sizes and shapes adapted for chewing many kinds of food - variety is mainly observed in mammals and is one reason for their success

Question 26

Mammals and digestive tract

Answer 26

Large expendable stomachs are common on carnivorous vertebrates - need to eat large when they can, long intervals between feeding Herbivores and omnivores have longer alimentary canals relative to body size as compared to carnivores - vegetation is more difficult to digest rather than meat because of cell walls - longer digestive tract furnishes more time for digestion and more surface area for absorption of nutrients

Question 27

Gut micrbiome - adaptation of cows

Answer 27

We coexist with beneficial microbes living in the intestine

Question 28

mutalistic gut micrbiome is important

Answer 28

in herbivores Vertebrates can not digest cellulose cell wall of plants to convert it to energy Many herbivores host mutualistic bacteria and protists in fermentation chambers of their alimentary canals - microorganisms digest cellulose to simple sugars that the animal can absorb

Question 29

Ruminants like cows

Answer 29

mix their food with mutalistic microbes in their multiple stomachs and regurgiate/rechew them before full digestion

Question 30

three main groups of primates

Answer 30

lemurs, lorises, bush babies tarsiers anthropoids: monkeys/apes

Question 31

earliest known primates were

Answer 31

tree dwellers All primates have thumbs that is separate from other fingers to easily grasp branches All monkeys and apes have fully opposable thumbs - can touch the ventral (fingerprint) side of all 4 fingers with the ventral surface of the thumb

Question 32

primate properties

Answer 32

- eyes on one side of the face (overlapping vision) gives better depth of perception - Large brain, short jaws and flat face Well developed parental care and complex social behaviour

Question 33

Apes

Answer 33

Gorilla (gorilla sp.) Humans (homo sp.) Chimpanzees (pn sp.) Shared traits for apes - usually larger than monkeys - no tail - only gibbons and orangutans are primary arboreal (lives on trees) No bipedal locomotion yet

Question 34

Hominins

Answer 34

Extinct species which are more closely related to humans than to apes Bipedal locomotion seen in early hominins (6.5 million years ago) Multiple lineages of bipedal hominins existed throughout the history of evolution We (homo sapiens) are the only hominin lineage which survived; others are extinct

Question 35

hominins invention

Answer 35

use of tools may have evolved after bipedal locomotion evidence shows hominins cutting flesh from bones of animals other non hominin apes can use tools too - orangutans putting sticks into holes to fish food

Question 36

Genus homo

Answer 36

early homo all spread from africa into europe/asian regions as they diversified homo habilis 2.4-1.6 million years ago Homo ergaster 1.9-1.5 million years ago

Question 37

Neanderthals

Answer 37

Homo neanderthalensis - burying dead - hunting tools from stone and wood extinct 28000 - 40000 years ago Is a different lineage as compared to humans but some gene flow did exist between the two species via inbreeding

Question 38

Homo sapiens (human)

Answer 38

200000 years old (0.2 million) Bipedal locomotion Language, symbolic thought, artistic expression, manufacture and use of complex tools reduced jawbone, jaw muscles, shorter digestive tract

Question 39

Scientific classification of human

Answer 39

Domain: Eukaryota Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primate Family: Homindae Genus: Homo Species: Homo sapiens

Question 40

many cave paintings were drawn since at least

Answer 40

30000 years ago

Question 41

Life on earth

Answer 41

Sunlight -> plants (oxygenic photosynthesis, mutalistic bacteria make provide other nutrients like nitrate) -> Cow (eats grass and produces milk with mutalistic bacteria help) -> milk -> yogurt (fermentation by gram positive bacteria) -> human consumption