cycle 10

Question 1

all cellular life…

Answer 1

• made of cells
• contains DNA
• DNA->RNA->proteins/enzymes (use the same proteins/enzymes to do this… e.g. ribosomes, polymerases)
• use the same energy currency (ATP, generated by same proteins/enzymes)
• all cellular life shares around 50 genes

Question 2

where did life originate?

Answer 2

an environment similar to a hydrothermal vent (underwater volcano that releases important metal ions that release electrons needed for ETC to make ATP)

Question 3

LUCA

Answer 3

• cellular
• prokaryotic, likely bacterial
• anaerobic
• autotrophic

Question 4

1st organism to evolve

Answer 4

bacteria

Question 5

what evolved after bacteria?

Answer 5

archaea (evolved cell membrane/cell wall)

Question 6

what evolved after archaea?

Answer 6

eukaryotes (evolved membranous structures, mitochondria, mitosis/meiosis)

Question 7

how did archaeal cells evolve membrane-bound organelles?

Answer 7

infolding of the cell membrane (e.g. nuclear envelope, endoplasmic reticulum, Golgi complex)

Question 8

how did archaeal cells evolve mitochondria?

Answer 8

endosymbiosis- aerobic heterotrophic bacterium becomes an endosymbiont inside an archaeon and loses genes needed to live on its own (transferred to host), become mitochondria

Question 9

mitochondria/chloroplasts

Answer 9

• have circular DNA
• encode genes to make ribosomes and other proteins/enzymes
• more are made through division
• membranes contain proteins for ETC

Question 10

how did eukaryotic evolve chloroplasts?

Answer 10

endosymbiosis- photosynthetic bacterial symbiont (cyanobacteria) becomes an endosymbiont in eukaryotes with mitochondria

Question 11

3 domains of life

Answer 11

bacteria, archaea, eukaryotes (plants, animals, fungi, protists)

Question 12

what evolved after eukaryotes?

Answer 12

multicellular organisms

Question 13

opisthokonts (1st multicellular)

Answer 13

group of eukaryotes that includes animals (fungi->choanoflagellates)

Question 14

what evolved after choanoflagellates?

Answer 14

animals

Question 15

animals (1st evolved)

Answer 15

porifera-> cnidarians -> segmented invertebrates -> echinoderms

Question 16

what evolved after echinoderms?

Answer 16

chordates (animals with dorsal nerve cord)

Question 17

Cambrian explosion

Answer 17

after the evolution of chordates, sudden appearance of complex animals in fossil record

Question 18

what evolved after the Cambrian explosion?

Answer 18

vertebrates

Question 19

when did plants evolve to live on land?

Answer 19

after vertebrates evolved

Question 20

ordovician-silurian mass extinction

Answer 20

after plants evolved on land, 85% of sea life was lost

Question 21

what evolved after the Ordovician-Silurian mass extinction?

Answer 21

animals on land

Question 22

late Devonian mass extinction

Answer 22

after animals on land, 75% of animal species lost, vertebrates did not appear in fossil record for another 10 million years

Question 23

what happened after the late Devonian mass extinction?

Answer 23

diversification of animals on land, amphibians -> reptiles

Question 24

Permian mass extinction

Answer 24

after reptiles, 96% of animal species lost

Question 25

what evolved after the Permian mass extinction?

Answer 25

mammals

Question 26

Triassic-Jurassic mass extinction

Answer 26

after mammals, 50% of species lost, opened up habitats for dinosaurs to evolve, evolution of early mammals that exist today

Question 27

what evolved after the Triassic-Jurassic mass extinction?

Answer 27

marsupials/monotrenes -> placenta (due to retrovirus envelope gene= syncytin that promotes cell fusion) -> rodents/rabbits

Question 28

K/T mass extinction

Answer 28

after rodents/rabbits, 75% of animal and plant species lost, dinosaurs/large mammals/flowering plants lost, opened up habitat for diversification of mammals

Question 29

what evolved after the K/T mass extinction?

Answer 29

primates (lorises/lemurs -> tarsiers -> new world monkeys -> old world monkeys -> gibbons -> great apes)

Question 30

great apes (hominidae)

Answer 30

orangutans -> gorillas -> chimpanzees/bonobos -> australopithecus afarensis -> homo -> homo sapiens

Question 31

what makes humans unique?

Answer 31

bigger brain, upright posture, bipedal, precise grip, hairlessness, blushing, social and cultural cognition, language

Question 32

did humans evolve from chimps?

Answer 32

no, share a common ancestor

Question 33

hominins

Answer 33

from chimps to humans

Question 34

which hominins did homo sapiens coexist with?

Answer 34

Neanderthals and Denisovans, and probably others (likely interacted/interbred-gene flow occurred bc they have shared sequences)

Question 35

examples of human evolution

Answer 35

-adaptations to new food sources and new environments (amylase copy number, lactose tolerance, oxygen transport at high altitudes, pale skin at high latitudes), adaptations to parasites (immune receptors), brain size and language (FOXP2 regulatory gene), increase prevalence of median artery in forearm

Question 36

what does a larger brain allow for?

Answer 36

store more info, rapidly collect and process information, solve problems, create abstract ideas and images

Question 37

costs of bigger brains

Answer 37

20% of oxygen and energy, makes childbirth more difficult

Question 38

big brain hypotheses

Answer 38

1. ecological-inteligence hypothesis (tool use, language, planning) 2. social-intelligence hypothesis (cooperation, coordination, deception, coercion) 3. cultural-intelligence hypothesis (cooperative hunting, building shelter) 4. mating mind hypothesis (art, wordplay, humour, music -> mating success)