7.4 POPULATIONS IN ECOSYSTEMS

Abiotic and biotic features, abundance. community, population, transects and quadrats, succession.

ABIOTIC FEATURES:

• CO₂.

• O₂.

• H₂0.

• Temperature.

• Salinity.

• Light.

• Mineral Ions.

BIOTIC FEATURES?

• Pred-Prey relationships.

• Competition.

• Parasites.

• Symbiosis.

ABUNDANCE?

The number of individuals of a species in a given area.

COMMUNITY?

All of the organisms/populations present in a habitat.

DISTRIBUTION:

The geographical area where species can be found.

ECOSYSTEM:

• The environment and all the organisms that live in an area.

• Ecosystems are dynamic

NICHE:

• How an organism fits into its environment, where it lives and what it does there.

• Two species will the same niche will compete.

• Governed by adaptations to abiotic and biotic features.

POPULATION:

• Group of organisms of the same species occupying a particular space at a particular time.

• That can interbreed to produce fertile offspring.

HOW CAN POPULATION SIZE VARY?

• Effect of abiotic features.

• Effect of biotic features.

HOW TO CALCULATE POPULATION SIZE AFTER GAINING MEAN OF QUADRATS?

(Total area of habitat/quadrat area) x mean per quadrat.

SUCCESSION:

Process of change in the species structure of an ecological community over time.

LINCOLN INDEX?

ASSUMPTIONS OF M-R-C?

• Population size remains same (no births, deaths, immigrations, emigrations). Or birth and death rate is equal.

• Marks not lost.

• Marked have enough time to remix with population.

• Method of marking is not toxic.

• Method of marking does not increase visibility to predators.

WHY MAY M-R-C BE UNRELIABLE IN LARGE POPULATIONS?

CARRYING CAPACITY:

• The maximum size that a population can remain sustainable in a particular habitat.

• Once the carrying capacity is exceeded, the population declines because its environment can no longer support the excess numbers.

PRIMARY SUCCESSION:

Cannabis Helps Old Buddies Sleep. 🍃

1. Pioneer species colonise.

2. Pioneer species change abiotic conditions, less hostile.

3. More suitable for new species, less suitable for old, old outcompteted.

4. Biodiversity increases.

5. Stable climax community reached.

FEATURES OF A CLIMAX COMMUNITY?

EXPLAIN HOW CONSERVATION OF HABITATS INVOLVES MANAGING SUCCESSION?

DESCRIBE THE CONFLICT BETWEEN HUMAN NEEDS AND CONSERVATION AS WELL AS THE IMPORTANCE OF MANAGING THIS?