Mid Term

Question 1

What are sources of energy used by life?

Answer 1

1. ) light
2. ) inorganic compounds (h2,h2s)
3. ) organic compounds (starch, fat)

Question 2

Autotroph

And two examples of autotrophs

Answer 2

“Self feeding”
Uses inorganic compounds + outside E to make organic molecules

Ex photo autotrophs: use light and Co2 to make glucose

Chemoautotrophs: use chemical E, CO2 to make glucose

Question 3

Heterotroph

And two examples of heterotrophs

Answer 3

“Different feeding”
Use organic compounds such as carbon source to make organic molecules

Ex.) chemoheterotrophs: consume organic molecules as both energy source and C source to transfer into other molecules (animals fungi many bacteria)

Photoheterotrophs: use light as energy but get C from food ( some bacteria)

Question 4

Why is life so diverse?

Answer 4

Evolution

Question 5

How did life start?

Answer 5

1. ) early pre O2 atmosphere & zap with lightning
2. ) this forms monomers (amino acids, nucleotides, sugars)
3. ) place monomers in favourable locations for condensation reactions (clay shores, hydrothermal vents, hot pools)
4. ) RNA before DNA -simpler -acts as a catalyst
5. ) lipids naturally form bilayer spheres which encapsulate RNA providing a more stable environment
6. ) self replication structure -> nucleus acid inside the nucleotides on outside

Question 6

Evolution

Answer 6

Genetic change in population of organisms over successive generations

Question 7

How do scientists work out evolutionary relationships?

Answer 7

Look for similarities and differences:

• fossil record
• morphological comparisons
• development
• molecular analyses
• behaviour

Question 8

Why is chocking so common in humans?

Answer 8

Because the lungs evolved from the esophagus

Question 9

Clade:

Answer 9

A monophyletic group (includes ancestral group and all its descendants)

Question 10

What are the 3 universal characteristics of life?

Answer 10

1. ) transform energy to synthesize new molecules (energy transformation)
2. ) make nearly faithful copies of themselves (reproduce)
3. ) regulate internal environment (maintain homeostasis) in response to external changes.

Question 11

Taxon:

Answer 11

a named group of organisms at any level of a phylogenetic tree, eg mammals or Homo sapiens

Question 12

Polytomy:

Answer 12

Populations likely split very rapidly from each other, making it hard to resolve which split off earlier or later

Question 13

Paraphyletic

Answer 13

Common ancestor group missing a descendant

Question 14

Polyphyletic

Answer 14

Group where a descendant doesn’t belong

Question 15

Monophyletic:

Answer 15

Common ancestor group with all descendants included

Question 16

Homology

Answer 16

Shared ancestry (homology)

Question 17

Homoplasy

Answer 17

Similarity due to convergent evolution -similar function

Question 18

Physical changes over time

Answer 18

• movement of continents = continental drift
• volcanic activity, meteorite collisions
• rise and fall of sea levels
• changing temperature
• increase in O2

Question 19

Life is affected by physical changes to earth, but life itself also brings about physical changes to earth

Answer 19

• no O2
• O2 = light E splits h2o & free electrons are used to reduce co2 to build organic molecules
• O2 is waste product
• leads to aerobic respiration
• supports more complex life (eukaryotic, multicellular)

Question 20

Cyanobacteria

Answer 20

Photosynthetic prokaryotes

Formed stromatolites

Question 21

Cambrian explosion

Answer 21

• oxygen levels made big, mobile animals possible
• the evolution of predation exerted selection for hard parts, exoskeletons, and rapid movement
• animals moved from ocean floor which led to development of new habits
• new genes, new bodies hox genes evolved

Question 22

What are the earths oldest organisms?

Answer 22

Bacteria

Question 23

Defining characteristics of archaea

Answer 23

Absence of peptidoglycan in cell wall

Distinctive lipids present in their cell membrane

Question 24

Plasmid

Answer 24

Extra-chromosome DNA, small rings, easily exchanged during sex

Question 25

Bacterium structure includes :

Answer 25

``` Capsule Cytoplasm Ribosomes Nucleoid Plasma membrane Flagellum Peptidoglycan Outer membrane ```

Question 26

Gram positive : | Gram negative:

Answer 26

Thick cell wall | Thin cell wall between 2 membranes ( typically antibiotics are ineffective against gram negative bacteria )

Question 27

The three challenges of a bacteria

Answer 27

1. ) make nearly faithful copies of themselves (reproduce) 2. ) respond to the outside environment by resisting internal changes in physical and chemical environments ( maintain homeostasis 3. ) transform energy to synthesize new molecules (energy transformation)

Question 28

Reproduction in bacteria

Answer 28

Rapid short generation times Asexual reproduction = binary fission

Question 29

Exchange of genetic material in bacteria 3 methods

Answer 29

Conjugation: genes on plasmids are easily transferred ( genes transferred through sex pilus Transformation: (uptake of free genetic material) Transduction (via viruses: bacteriophages)

Question 30

Maintain homeostasis

Answer 30

Respond to harsh environmental conditions Move toward or away from chemicals

Question 31

Endospores

Answer 31

Protect bacteria from adverse conditions ( auto cave must be use to kill them)

Question 32

Biofilms

Answer 32

Bacteria form surface- coating communities - form polysaccharide gel trapping debris and other cells - can be hundreds of cells thick - composed of single or many species

Question 33

Chemotaxis

Answer 33

Bacteria are able to move toward or away from chemical signals - use flagella (different than eukaryotes) - made from different proteins - thinner & more numerous - also glide roll use gas floats inside cell

Question 34

Paleozoic

Answer 34

Marine organisms | Ended with massive extinction 75% because of sea level and ocean temperature drop

Question 35

Silurian

Answer 35

Marine life rebounded | Animals swim and feed a

Question 36

Optimal hydration

Answer 36

Avoid dehydration of the body

Question 37

What is diversity?

Answer 37

1. ) genetic variation 2. ) Species composition 3. ) function (eg biochemical pathways)

Question 38

Paleozoic

Answer 38

Marine organisms | Ended with massive extinction 75% because of sea level and ocean temperature drop

Question 39

Silurian

Answer 39

Marine life rebounded | Animals swim and feed a

Question 40

Optimal hydration

Answer 40

Avoid dehydration of the body

Question 41

What is diversity?

Answer 41

1. ) genetic variation 2. ) Species composition 3. ) function (eg biochemical pathways)

Question 42

Vestigial trait

Answer 42

A reduced structure no function anymore

Question 43

Developmental homology

Answer 43

Recognized in embryos