Chapter 2 Origin and Diversity of Life

Question 1

What was the composition of early earth?

Answer 1

• no free O2

- CO, CO2, N2, H2, S, HCl, HCN

Question 2

How did oceans form?

Answer 2

cooling -> condensation of water vapour -> rain -> oceans

Question 3

What does the Oparian- Haldane hypothesis suggest?

Answer 3

• reducing environment of early earth
• simple molecules became primordial soup of organic monomers
• upon exposure to UV light, lightning, radioactivity, heat

Question 4

Miller-Urey Experiment…

Answer 4

tested Oparian Haldane hypothesis by providing early earth conditions (H2, N2, CO, CO2, HCl, HCN) with electric current to simulate lightning
- synthesis of complex organic molecules from simple inorganic

Question 5

“self-replicating genetic material like RNA was earliest life form that eventually became self-sustaining through metabolic networks” defines what?

Answer 5

RNA World (Naked Gene) Hypothesis

Question 6

“isolated environments allowed formation of metabolic networks that eventually became earliest life form” defines what hypothesis?

Answer 6

Metabolism-First hypothesis

hypothesis for early forms of life

Question 7

What are protobionts?

Answer 7

primitive cells that formed isolated environment for chemical reactions to occur

Question 8

What are 2 types of protobionts?

Answer 8

coacervates (lipid spheres)

microspheres (polypeptide spheres)

Question 9

What is the earliest autotroph and what is it known for?

Answer 9

cyanobacteria

• O2 byproduct
• formation of ozone layer
• creation of oxygen rich environment today

Question 10

What is the endosymbiotic theory?

Answer 10

engulfment of one prokaryote led to another mutually beneficial association to form the modern eukaryote
- mitochondria and chloroplast

Question 11

What are bacterial cell walls made up of?

Answer 11

peptidoglycans - sugar polymer with amino acids

Question 12

What are plant cell walls made up of?

Answer 12

cellulose

Question 13

What are fungal cell walls composed of?

Answer 13

chitin - sugar

Question 14

What is a difference between archaea and eubacteria in terms of DNA?

Answer 14

• archaea is packed in histones

- bacteria is naked circular bacterial DNA

Question 15

What are Archaea cell walls composed of?

Answer 15

polysaccharides

Question 16

What is an endospore?

Answer 16

non-reproductive structure containing bacterium’s DNA (protect DNA)

Question 17

What are filaments of fungi called? What do they form?

Answer 17

hyphae

mycelium

Question 18

What is the role of septa in fungi?

Answer 18

divides it into compartments, each with a single nucleus

Question 19

Are fungi autotrophs or heterotrophs?

Answer 19

• heterotrophs
• absorb the breakdown products from digestive enzymes that they secrete
• therefore parasites or saprobes

Question 20

What are haustoria?

Answer 20

hyphae (fungi filaments) that penetrate host

Question 21

Do fungi reproduce sexually or asexually

Answer 21

both!

Question 22

How do fungi reproduce sexually?

Answer 22

• fungi are normally haploid,

- must be diploid to reproduce

Question 23

What is plasmogamy?

Answer 23

• two normal haploid fungi cells fuse to form single cell with 2 haploid nuclei = dikaryon

Question 24

What is a dikaryon?

Answer 24

single cell with 2 haploid nuclei

Question 25

What is karyogamy?

Answer 25

dikaryon forms single diploid nucleus (2 nuclei one cell to one nuclei one cell)

Question 26

What is the final step to sexual reproduction of fungi?

Answer 26

meiosis of the newly formed diploid cell

Question 27

Fungi asexual reproduction can occur via fragmentation, budding, and asexual spore production. How are spores formed?

Answer 27

- sporangiospores are in sac like capsules = sproangia | - conidia are not in capsules

Question 28

Where are sporangia found?

Answer 28

sporangia at stalks of of sporangiophores

Question 29

Where are conidia found?

Answer 29

not in capsules at hyphae called conidiophores

Question 30

What is the eumatazoa and parazoa group?

Answer 30

eukaryotic anamalia tissue differences - eumatazoa tissue layers that develop into organs - parazoa group do not have tissue layers or organs

Question 31

Which phyla of kingdom anamalia are deuterosomes?

Answer 31

chordates and echinodermata (sea urchins and star fish - most similar phyla to chordata)

Question 32

This organism reproduces asexxually, has asymmetrical symmetry and is a parazoa. What phyla of anamalia is it?

Answer 32

Porifera parazoa means no true tissues they are immobile and are the earliest form of animals

Question 33

This organism has a two way digestive tract, but no coelom. What phyla does it belong to?

Answer 33

Platyhelminthes (flatworms) coelom is the main body cavity excretory system has flame cells - filters harmful substances

Question 34

This organism has a one way digestive tract in the soil. What is this?

Answer 34

Nematoda (roundworms) - pseudocoelom

Question 35

This organism has one way digestive tract and gills for respiration. It has a mantle as well. What phyla?

Answer 35

Mollusca - one way digestion - coelom - gills - live in aquatic or land - mantle: thin layer of tissue that builds shells

Question 36

This phyla has one way digestion and a coelomate (true body cavity). They have segmented circular bodies.

Answer 36

Annelida | earthworms and leeches

Question 37

Arthropods have one or complete digestive system (start and end)?

Answer 37

one way | - exoskeleton

Question 38

Name example of echinodermata.

Answer 38

Starfish, sea urchins

Question 39

Do echinodermata have one way or complete digestive systems?

Answer 39

complete digestive system | = deuterosome

Question 40

What is the difference between some vertebrates such as birds and reptiles in comparison to humans (chordata) in terms of excreting waste?

Answer 40

birds and reptiles secrete uric acid | humans secrete urea

Question 41

Chordates are only vertebrates. True or false?

Answer 41

False. Chordates can be separated into vertebrates and invertebrates. *chordates means development of the notochord during embryonic development

Question 42

What does the dorsal hollow nerve cord become after embryonic development?

Answer 42

spinal cord and brain

Question 43

What does the notochord become after embryonic development of chordates?

Answer 43

vertebral column (bone) and muscles

Question 44

Embryonic chordates have gills. True or false.

Answer 44

True. | Pharyngeal gill slits becomes gills, pharynx or feeding mechanism

Question 45

Parenchyma, Collenchyma, Sclerenchyma are classes of ____

Answer 45

ground tissue of plant cells: these provide structural support

Question 46

What tissue is the site of photosynthesis in ground tissue of plants?

Answer 46

parenchyma

Question 47

What is the role of dermal tissue? | - 2 types

Answer 47

protection from dehydration - epidermal layer - guard cells (stomata = opening)

Question 48

Xylem transports __ and Phloem transports ___

Answer 48

xylem: water (up) phloem: sugars (down)

Question 49

Xylem + Phloem = (term)

Answer 49

vascular bundles

Question 50

In the vascular bundles, some tissues are dead and some are living at maturity. Which is which?

Answer 50

phloem is living - but no nuclei or ribosomes | xylem is dead tissue - therefore no cellular components

Question 51

If there are no cellular components or nuclei in vascular bundles (depending on the type of tissue) how do they carry metabolic needs of the cell?

Answer 51

- metabolism is conducted via parenchyma connection via plasmodesmata

Question 52

What is the casparian strip in roots?

Answer 52

band of fatty material between endodermis = suberin | - water impermeable barrier

Question 53

What are the parts of the stem?

Answer 53

epidermis cortex vascular cylinder (xylem, phloem, pith)

Question 54

Where is vascular cambium located and what is it?

Answer 54

- undifferentiated cells that are between xylem and phloem

Question 55

What are the female parts of a flower (angiosperm)

Answer 55

pistil: ovary (swollen part with gametophytes) style (stalk) stigma (top)

Question 56

What are the reproductive male parts of the flower?

Answer 56

anther (microspores) | filament (stalk)

Question 57

Prior to fertilization, the megaspore mother cell in the ovule goes through meiosis. What is the result of these divisions?

Answer 57

- embryo sac with micropyle (opening) - egg cell - two synergid cells - 3 antipodal cells - 2 haploid polar nuclei

Question 58

What structures are fertilized of the female gametes?

Answer 58

- haploid egg cell fertilized as pollen enteres micropyle - polar nuclei forms triploid nucleus to produce endosperm (nourishment) = double fertilization

Question 59

What is auxin?

Answer 59

plant hormone that promotes ELONGATION

Question 60

What is gibberelins?

Answer 60

plant hormone that promotes cell growth

Question 61

What is cytokinin?

Answer 61

plant hormone that stimulates cell division

Question 62

What is ethylene?

Answer 62

gas that promotes fruit ripening or flower production

Question 63

What is abscisic acid (ABA?

Answer 63

growth inhibitor that can maintain dormancy in seeds

Question 64

What is phototropism?

Answer 64

- sunlight affecting the side that plant will gorw - auxin

Question 65

What did lobe-finned fish evolve from?

Answer 65

jawless fish -> cartilaginous fish -> lobe-finned fish

Question 66

What are the significant steps of evolution in order for chordates?

Answer 66

- notochord (lancelets and tunicates) - head (hagfish) - vertebral column (jawless fish) - jaw and mineralized skeleton (sharks) - lungs (rayfinned fish) - lobed fins - limbs with digits (amphibians) - amniotic eggs (reptiles) - production of milk (mammals)

Question 67

Apoplastic vs Symplastic?

Answer 67

Water moves through cell walls = apoplastic | Symplastic = moves through one cell to the other via plasmodesmata - through the cytoplasm connected