Lab 1 practice Flashcards
95% of our food come from 20 species of plants. 80% of our food come from…
6 species of plants.
What are the three main grasses consumed by humans?
- wheat
- corn
- rice
What are the top six species of plants consumed by humans?
- wheat
- corn
- rice
- maize?
- potatoes
- cassava
The earliest fossils date back to
3.8 bya
The earliest fossils were…
prokaryotes
True or False. The atmosphere of earth before photosynthesis was a reducing atmosphere.
true.
Earliest evidence of photosynthesis dates to…
3.5 bya
What in fossils showed that photosynthesis was occuring?
the iron became oxidized
the two consequences of having more oxygen in the atmosphere were:
- some became ozone, which filters UV rays. This made it possible for organisms to survive out of water.
- the increased amount of oxygen lead to more efficient respiration (aerobic respiration now possible.)
Though not agreed upon, the first eukaryotes are dated to…
around 1.5 bya
Multicellular organisms are dated to around…
650 mya
Multicellular organisms had an advantage because
they were better able to cope with wave action.
Around 420 mya, land plants began to populate. How did they solve the challenge of not drying out (resisting desiccation?)
they formed an epidermis with a cuticle to reduce dessication.
As the land plants populated and ran out of room, they began to grow upward toward the light. What advantage solved this challenge?
stem to grow tall and position leaves in light.
As plants grew farther away from the ocean, the environment becomes drier. How was this challenge solved?
plants began to grow roots to reach subsoil layers where there was still moisture.
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?
the phloem (moves sugar or food) and the xylem (moves water.)
As more plants grew tall, competition for light became a challenge. How was this challenge addressed?
stems became taller, thicker, created stronger tissues for support.
Do plants have determined growth?
No, they have indeterminant growth. (keep growing their whole life.)
True or False. Plants have a closed system of growth.
False. They have an open system of growth with no set amount of organs
What are the three major plant organs?
roots, stems, leaves
Reproduction on land was a challenge due to the dry environment. How was this overcome?
plants grew spores that could resist desiccation. Then, later, the reproductive structures were closed in protective tissue. Then some plants developed seeds.
