Lab 1 practice

Question 1

95% of our food come from 20 species of plants. 80% of our food come from…

Answer 1

6 species of plants.

Question 2

What are the three main grasses consumed by humans?

Answer 2

1. wheat
2. corn
3. rice

Question 3

What are the top six species of plants consumed by humans?

Answer 3

1. wheat
2. corn
3. rice
4. maize?
5. potatoes
6. cassava

Question 4

The earliest fossils date back to

Answer 4

3.8 bya

Question 5

The earliest fossils were…

Answer 5

prokaryotes

Question 6

True or False. The atmosphere of earth before photosynthesis was a reducing atmosphere.

Answer 6

true.

Question 7

Earliest evidence of photosynthesis dates to…

Answer 7

3.5 bya

Question 8

What in fossils showed that photosynthesis was occuring?

Answer 8

the iron became oxidized

Question 9

the two consequences of having more oxygen in the atmosphere were:

Answer 9

1. some became ozone, which filters UV rays. This made it possible for organisms to survive out of water.
2. the increased amount of oxygen lead to more efficient respiration (aerobic respiration now possible.)

Question 10

Though not agreed upon, the first eukaryotes are dated to…

Answer 10

around 1.5 bya

Question 11

Multicellular organisms are dated to around…

Answer 11

650 mya

Question 12

Multicellular organisms had an advantage because

Answer 12

they were better able to cope with wave action.

Question 13

Around 420 mya, land plants began to populate. How did they solve the challenge of not drying out (resisting desiccation?)

Answer 13

they formed an epidermis with a cuticle to reduce dessication.

Question 14

As the land plants populated and ran out of room, they began to grow upward toward the light. What advantage solved this challenge?

Answer 14

stem to grow tall and position leaves in light.

Question 15

As plants grew farther away from the ocean, the environment becomes drier. How was this challenge solved?

Answer 15

plants began to grow roots to reach subsoil layers where there was still moisture.

Question 16

Deeper roots created the challenge of needing to transport water and sugar from one part of the plant to the other. What two parts of the vascular system in plants overcame this challenge?

Answer 16

the phloem (moves sugar or food) and the xylem (moves water.)

Question 17

As more plants grew tall, competition for light became a challenge. How was this challenge addressed?

Answer 17

stems became taller, thicker, created stronger tissues for support.

Question 18

Do plants have determined growth?

Answer 18

No, they have indeterminant growth. (keep growing their whole life.)

Question 19

True or False. Plants have a closed system of growth.

Answer 19

False. They have an open system of growth with no set amount of organs

Question 20

What are the three major plant organs?

Answer 20

roots, stems, leaves

Question 21

Reproduction on land was a challenge due to the dry environment. How was this overcome?

Answer 21

plants grew spores that could resist desiccation. Then, later, the reproductive structures were closed in protective tissue. Then some plants developed seeds.