Life and the physical environment

Environment:

- Necessities

- Light

- Temperature

- Water

- Nutrients

Biogeography:

- Ecological (analitical):

○ Focused on the individual organism

○ Analitical:

§ Interaction with the biological and abiological

- Historical

Biomass:

- Biological productivity is an important measure of the health of an ecosystem

- Limited by the ability of plants' photosynthesis

Tolerance threshold & optimum range

Zone of physiological stress:

- The plants are not in their ideal conditions, but they can still thrive

Morhpological assets of plants... derive from their ideal habitat (where they are living)

Photosynthesis can reach a maximum:

- Reaching it can lead the photsynthesis to decline

- Compensation point:

○ Uses energy and needs to compensate for that

□ Respiration and photosynthesis start to decline

- Saturation point:

○ Doesn't go further

○

Light and photosynthesis:

- 1/3 to 2/3 sunlight to NPP (Netto)

- Photoinhibation:

○ Plants that thrive with less than 5% sunlight

§ Sciophytes

○ Heliophytes

§ C3 path of photosynthesis

Aphotic zone (aquatic)

- 20-100 m deep

- 1-3% sunlight required

- Saturation at 5% sunlight

Light (wavelength):

High light intensity and UV can damage chloroplasts (grænukorn)

- Reduces photosynthesis

- Impairs growth, mutation and death

Duration and timing:

- Heliophytes - annual flowering (completes life cycle in a year)

- Sciophytes - perennial (2 seasons)

○ There are always exeptions

Phenology:

- Seasonal change within an organism

Photoperiodism:

- The interaction of phenology and light

Changing of the color of leaves:

- They put the energy to the roots and store it there

○ That way they loose their color

Light :

- Two types of light sensor in plant cells

○ Phytochrome:

§ Sensitive to red and infrared light (triggers, germination, growth etc.)

○ Cryptochrome:

§ Sensitive to blue and UV light

Caretonoid:

- Hibernation/nutrition

Anthocyan:

- UV protection:

○ Created when chloroplast is broken down

Temperature:

- Majority of plants are poikilotherms

○ Assume the temperature of their surounding environment

§ Absorbtion of water...

□ Leaves can be colder than their environment

Photosynthesis is always above 0°C

Water:

- Cell growth

- Turgor (structure)

- Temperature regulation

- Protein synthesis

- Transport of nutrients

Poikilohydry:

- Lacks the sructure to regulate water moisture secured from the atmosphere

- Slow growing

- Cells resistant to damage when dry

○ T.d. mosi

Homiohydric:

- Can draw water through their root system

- Don't cope well with droughts

Transpirtation:

- Via the stomata of a vascualar plant

○ Atmospheric pressure greater thanthat within the stomata of the leaves

Dehydration:

- Loss of turgor (wilting)

- Stomata closes

- Reduces photosynthesis

- Cell death

Nutrients:

- Are essential to life

○ Salt:

§ Particularly important to life

§ Can alter metabolic function

□ Can result in death

§ Pure water (fresh) moves toward salt water

Geographic range; density; carrying capacity...

Geographic range:

- The entire area occupied by a species regardless of whether it is rare or common

Density:

- Density of a species can often be found at the center of its optimum geographic range

Carrying capacity:

- Number of individuals an area can support

- There's usually a match between optimum environmental condition and carrying capacity

Niches:

- Generalist

- Specialist:

Can only tolerate a certain environmental envrionment