Moving onto Land

Question 1

Proterozoic beginning

Answer 1

beginning of proterozoic
primarily bacteria/archaea
great oxygenation event

Question 2

importance of ozone layer

Answer 2

filtered out harmful UV radiation

Question 3

Proterozoic end

Answer 3

eukaryotes evolve
photosynthesis evolves (algae)
soft animals, hard bodied animals appear
ozone layer formed from great oxygenation event

Question 4

Cambrian (3)

Answer 4

shells and hard bodies dominate
animals become more motile (so predation)
explosion of evolution of new body types in animals
chordates evolve (long central nerve) (pikaia)

in water!

Question 5

Ordovician (450 MYA)

Answer 5

rising and falling sea levels
first true vertebrates (fish with jaws)

Question 6

Barriers: Harmful UV radiation

Answer 6

water could filter UV light which could protect life
ozone could filter out some but not still needed some protection

Question 7

Barriers: Desiccation

Answer 7

Aquatic organisms dry out easily, not waterproof
smaller organisms dry out faster

Question 8

Barrier: Gas exchange

Answer 8

Gases (CO2 and O2) are absorbed differently depending on where they are
needed a new system of gas exchange

Question 9

Barrier for animals: Buoyancy

Answer 9

Water and water pressure supports body tissues, air does not
needed supporting structures

Question 10

Barrier: Temperature fluctuations

Answer 10

Seawater: slow and little temp change over centuries
land: big changes

Question 11

Barrier: Mineral nutritition

Answer 11

water contains dissolved minerals for added nutrition that they couldn’t get easily on land

Question 12

Barrier: Reproduction

Answer 12

Aquatic organisms need water to facilitate reproduce for gametes

Question 13

Barrier: Visions and hearing

Answer 13

Light and sound waves move differently through water compared to air

Question 14

First Colonizers

Answer 14

cyanobacteria –> green algae
plants are autotrophs, advantageous to grow near the surface in shallow waters
exposed to periods of drought in the intertidal areas
selected for individuals that could tolerate desiccation, evolved into Moss and liverwort

Question 15

Plant Adaptation to Life of Land

Answer 15

liverworts + mosses –> more adaptions to life on land
took millions of years

Question 16

Plant Adaption: dessication

Answer 16

a layer of surface wax (cuticle)
roots, root-like structures to get water

Question 17

Plant Adaption: gas exchange

Answer 17

specific pores (stomata) allows for gas to enter or stay shut

Question 18

Plat Adaption: Reproduction

Answer 18

evolved spores which could survive desiccation but still needed water to move
eventually seeds

Question 19

Plant Adaptations: Buoyancy

Answer 19

developed lignin and cellulose for structural support

Question 20

Plant Adaptation: Temp fluctuation

Answer 20

more traits to prevent drying out and survive extreme temperature changes

Question 21

Plant Adaptation: Mineral nutrition

Answer 21

roots allowed plants to take minerals minerals right out of the soil
some plants formed symbiotic associations with fungi

Question 22

When did animals move onto land? when did plants

Answer 22

late silurian to early devonian

Ordovician for plants
though some arthropods my have fleed onto land temporarily

Question 23

Our ancestors moving onto land

Answer 23

Tikaalik (a lobe-finned fish) in late devonian
sturdy jointed arms for terrestrial support
evolution of limbs but still closely tied to water for reproduction

Question 24

Animal Adaptations: Dessicaiton

Answer 24

waxy coating, scales, concentrate, live in damp habitats

Question 25

Animal Adaptations: Gas exchange

Answer 25

insects: small openings in exoskeleton
vertebrates: trachea and lungs

Question 26

Animal Adaptations: Reproduction

Answer 26

Internal fertilization, keeps them wet, maxs probability of gametes encountering one another
amniotic egg –> live birth (viviparity)

Question 27

Animal Adaptation: Buoyancy

Answer 27

exoskeleton or external shell or internal skeleton of cartilage and bone

Question 28

Animal Adaption: Temp fluctuation

Answer 28

homeothermy = ability to regulate internal body temp temp
metabolism or behavior
metabolism needs more energy

Question 29

Animal Adaptation: Vision

Answer 29

early eyes: filled with water from the environment
sealed chamber filled with fluid

Question 30

Animal Adaption: Hearing

Answer 30

adapted for airborne wavelengths, cochlea still contains fluid for sound transmission