SNC1D Biodiversity

Equilibrium The state of an ecosystem with relatively constant conditions Abiotic (non-living) conditions are stable Energy flow through the system (food chains) Nutrients are cycled Photosynthesis in balance with cellular respiration

Biodiversity: the variety of life in a particular ecosystem

Monoculture: an environment with very low biodiversity Monocultures are very vulnerable to ecological collapse: when all living things in an ecosystem die.

High biodiversity leads to sustainable ecosystems. In part, due to redundancy in the food web. If the number of rabbits decreases, the foxes can still eat squirrels.

Biodiversity Under Attack Humans are rapidly destroying Earth's ecosystems and along with them, many species, some we don't even yet know exist.

Species at Risk Extinct: a species that has died out and no longer exists anywhere on Earth Example: Passenger pigeon

Species at Risk Extirpated: a species that no longer exists in a specific area in the wild but still lives elsewhere Example: Atlantic walrus in Northwest Atlantic

Endangered: a species facing imminent extirpation or extinction Species at Risk Endangered: a species facing imminent extirpation or extinction Example: Swift fox

Species at Risk Threatened: a species that is likely to become endangered if factors reducing its survival are not changed Example: Humpback whale

Species at Risk Special Concern: a species that may become threatened or endangered because of a combination of factors Example: Polar bear

Habitat: the natural environment in which an organism lives, included food and shelter Habitat fragmentation: remaining wild areas are divided into smaller parts Many organisms lose their habitat to human development (cities, farms, etc.).

Factors Affecting the Sustainability of Habitats Size: large blocks support larger and therefore more stable populations and communities One large block is better than an equal area of smaller blocks.

Factors Affecting the Sustainability of Habitats Proximity: the closer areas are to each other, the greater the chance populations will be able to interact Wildlife corridors connect areas and further increase the chance of interaction.

Factors Affecting the Sustainability of Habitats Integrity: access by roads and trails can increase pollution, hunting, and fishing

Factors Affecting the Sustainability of Habitats

HOMEWORK Read page 80 (stop at Ecological Succession) Answer pg 82 # 1 & 9 Read pages 83-90 Answer pg 86 #1-7 Answer pg 90 #1-6