Complex multicellular organisms that are primarily terrestrial autotrophs and produce theri own organic molecules by photosynthesis
What does terrestrial?
Plants are a __________ group of organisms ___ _________.
Dominant, on land
What happened when photosynthetic algae began to produce oxygen?
The oxygen accumulated in the atmosphere and some of the oxygen gas was converted to ozone
What produced the protective ozone layer?
When photosynthetic algae began to produce oxygen and it accumulated in the atmosphere where some of the oxygen gas was converted to ozone
The did the protective ozone layer do?
Shielded Earth's surface and could have allowed the invasion of terrestrial plants and fungi
What does multicellularity do?
Enable plants to develop the complex structures and associations that have contributed to their success on land
What were the three obstacles plants had to overcome in order to be terrestrial?
be able to absorb minerals from rocky surface
be able to conserve water
have a way to reproduce on land
What played a role in the initial occupation of land by plants?
A symbiotic relation between fungi and roots of plants
How do the plants benefit from the symbiotic relationship?
Fungi absorb phosphates and nitrates from the soil for the plant
How do fungi benefit from the symbiotic relationship?
Plants provide fungi with carbohydrates and other organic molecules made during photosynthesis
What is thought to have enabled the first plants to absorb minerals from Earth's rocky surface?
Mutualistic associations similar to mycorrhizae
About what percent of all living plant species form mycorrhizae?
Briefly explain how the symbiotic relationship between plants' roots and fungi works.
The fungal mycelium (structures on fungi that bring in nutrients) tranfer them to the root cells so that plant benefits and carbohydrates leave plant from photosynthesis and travel down to roots that tranfer them to the fungi
What can fungi do to absorb nutrients?
Break down rock
What is one of the key challenges for a plant living on land?
Avoiding drying out
Describe the first plants and where they lived.
Very small and lived at the edges of oceans
Why did the first plants live at the edges of the oceans?
Because then water was abundant since it would wash up over them, and then go back out constantly
How did plants adapt to needing to conserve water?
Developing a cuticle (waxy substance)
Why does the cuticle help conserve water?
Impermeable so water cannot pass through but instead runs off down to soil where roots can absorb it
What developed to enable plants to exchange gases? Why?
Specialized spores call stomata because cuticle impermeable to gases need for photosynthesis
What borders each stomata and what does it do?
A pair of guard cells that controls the stomata's size by expanding and contracting
What was unique about the eggs of the first plants?
Surrounded by jackets of cells and a film of water was required for sperm to swim to an egg and fertilize it
What two groups of primitive plants still require water to reproduce?
Mosses and ferns
What is unique about the gametes in advanced plants?
The sperm are enclosed in multicellular structures (pollen grains) that keep them from drying out and enable them to be transmitted to female gametes by wind or animals instead of water
How many sperm are in each pollen grain and why?
2 because....(ask Mr. Madrigal)
What is a Vascular System?
Veins, arteries and capularies (specialized strands of hollow cells connected end to end)
What three special tissues did plants evolve and develop once established on land?
What is unique about the cells of the vascular system today?
Run from near the tips of the roots to the tips of the stems and into the leaves
What do you call plants that have either no vascular system or very simple vascular tissue? Example.