Life and the physical environment

Environment

The necessities, light, temperature, water, and nutrients required for the survival of organisms.

Biogeography

The study of the distribution of organisms and their interactions with the biological and abiotic factors in their environment, including ecological and historical perspectives.

Biomass

The measure of biological productivity in an ecosystem, limited by the ability of plants to photosynthesize.

Tolerance threshold & optimum range

The range of environmental conditions within which plants can thrive, with the zone of physiological stress representing conditions less than ideal but still supportive of growth.

Morphological assets of plants

Characteristics of plants that are derived from their ideal habitat.

Photosynthesis

The process by which plants convert sunlight into energy, with a maximum point beyond which photosynthesis declines, and a compensation point where respiration and photosynthesis start to decline.

Light and photosynthesis

The importance of light in photosynthesis, with 1/3 to 2/3 sunlight required for net primary productivity (NPP), and the effects of photoinhibition on different types of plants.

Aphotic zone (aquatic)

The deep zone in water bodies where sunlight penetration is limited, with only 1-3% sunlight required and saturation at 5% sunlight.

Light (wavelength)

The effects of high light intensity and UV on chloroplasts, reducing photosynthesis and impairing growth, mutation, and death.

Duration and timing

The differences in flowering and life cycle duration between heliophytes (annual) and sciophytes (perennial), with exceptions.

Phenology

The seasonal changes within an organism.

Photoperiodism

The interaction between phenology and light.

Changing of the color of leaves

The energy transfer to roots and storage, resulting in the loss of color in leaves.

Light sensors in plant cells

Phytochrome (sensitive to red and infrared light) and cryptochrome (sensitive to blue and UV light).

Carotenoid

A pigment involved in hibernation and nutrition.

Anthocyan

A pigment providing UV protection, produced when chloroplasts are broken down.

Temperature

The majority of plants are poikilotherms, assuming the temperature of their surrounding environment, with photosynthesis always occurring above 0°C.

Water

The importance of water for cell growth, turgor, temperature regulation, protein synthesis, and nutrient transport.

Poikilohydry

Organisms lacking the structure to regulate water moisture from the atmosphere, slow-growing, and resistant to damage when dry.

Homiohydric

Organisms capable of drawing water through their root system but not coping well with droughts.

Transpiration

The process of water movement through the stomata of vascular plants, driven by atmospheric pressure.

Dehydration

The loss of turgor, closure of stomata, reduction in photosynthesis, and cell death due to water loss.

Nutrients

Essential elements required for life, with salt being particularly important and capable of altering metabolic function.

Geographic range

The entire area occupied by a species, regardless of rarity or commonness.

Density

The concentration of individuals of a species, often found at the center of its optimum geographic range.

Carrying capacity

The maximum number of individuals an area can support, usually matching the optimum environmental conditions.

Niches

Generalist and specialist organisms that can tolerate different environmental conditions.