Ecology

 

 

 

 

Ecological Relationships

 

Ecological Terms:

• Habitat: Place where an organism lives.
• Ecology: The study of living organisms and their interaction with each other and their environment.
• Ecosystem: A group of organisms that work with each other and with their environment. (Community of organisms + Environment)
• Biosphere: The part of the earth and its atmosphere within which life exists.
• Niche: The niche of an organism is its functional role in the habitat.
• Herbivore: Plant-eating organism.
• Carnivore: Meat-eating organism.
• Omnivore: Plant & meat-eating organism.

 

Environmental Factors:

• Abiotic factors: Non-living part of an ecosystem. (e.g. current, slope, altitude)
• Biotic factors: Living part of an ecosystem. (e.g. plants, organisms, food, predation)
• Climatic factors: Long term weather conditions. (e.g. temperature, wind, precipitation)
• Edaphic factors: Factors associated with soil. (e.g. pH, air content, water content, particle size, temperature, mineral content)

Energy Flow:

1. All ecosystems need energy to function.
2. The sun is the source of this energy.
3. This energy is trapped by plants during photosynthesis.
4. The energy is then passed from consumer to comsumer.
5. A large amount of energy is lost at each feeding level. (approx.90%)

 

Feeding Relationships in an Ecosystem:

Producers: Autotrophic organisms that can make their own food. e.g. grass.

Consumers: Heterotrophic organisms that cannot make their own food. e.g. animals.

Primary Consumers: Feed on producers.

Secondary Consumers: Feed on primary consumers.

Tertiary  Consumers: Feed on secondary consumers.

 

Food Chains:

A food chain is a feeding relationship between organisms in which energy is transferred.

e.g. Ash tree leaves -> Caterpillar -> Pigmy shrew -> Fox.

 

Food Web:

A food web is a series of interconnecting food chains.

 

A trophic level is a feeding relationship in a food chain.

 

Pyramid of Numbers:

A pyramid of numbers shows the relative number of organisms at each trophic level.

• In a pyramid of numbers, the primary producers are counted and put at the bottom of the pyramid.
• The number of organisms at each subsequent trophic level are then counted and placed accordingly in the pyramid.

 

Limitations of Pyramids:

1. Pyramids do not take into account the size of the organism.
2. When large numbers of organisms are in question, the pyramid takes on a distorted shape.

 

Types of Pyramids:

• Normal:

 

• Inverted:

 

• Parasitic:

 

Factors That Control Populations:

• Competition: The struggle between organisms for the limited resources in a habitat.

             2 Types of competition:

1. Scramble Competition: Where each organism tries to get as much of the resource as possible.
2. Contest Competition: Where two organisms fight over a resource with only one of them winning.

• Predation: This is the catching and killing of another organism for food.
• Parasitism: Relationship between two organisms in which one benefits and harms the other.
• Symbiosis: Close relationship between two organisms of different species in which at least one benefits.

 

Nutrient Recycling:

• The Carbon Cycle:

 

• The Nitrogen Cycle:

 

 

 

Effects of Humans in the Environment

 

Pollution: Is the addition of harmful substances to the environment.

Pollutants: are substances that cause pollution.

The effects of an activity & pollutant: (One only needed for LC)

1. Slurry- water pollution
   1. Effect: run-off from wet farmland causes algae bloom in nearby waterways- Eutrophication.
   2. Control: Don’t spread on wet land, avoid proximity to waterways and sloped land.
2. Ozone depletion- air pollution
   1. Effect: lack of ozone protection causes skin cancer, crop damage, and distortions’ in aquatic food chains.
   2. Control: replacement of CFCs with HFCs in chemical agents and recycling of non- biodegradable resources.

Conservation: it is the management of scarce resources to protect a variety of habitats and prevent organism extinction and death.

Conservation practices from fisheries:

• Established EU fishing quotas
• Increased fishing mesh sizes in nets to allow smaller fish to escape and reproduce

Waste Management Problems in waste disposal:

1. Agriculture: Slurry-causes eutrophication in rivers and results in depletion of fish stocks
2. Landfills release gaseous pollutants and are unsightly
3. Incineration causes air pollution

Micro-organisms e.g.: bacteria and fungi breakdown organic waste in landfills and sewage.

Sewage treatment is done in 3 stages:

Primary: involves screening and settling of physical waste.

Secondary: involves chlorination, fluorination and the bacterial decay of organic waste.

Tertiary: involves chemical removal of nitrates and phosphates.

Controls of waste production include:

• Reducing
• Reusing
• recycling