Ecology: Communities, Competition & Interdependence

Communities

• A species individual lives in a habitat within a population
• Different populations interact in a habitat, to form a community
• Populations depend on each other
• An ecosystem is the interaction of a community with abiotic parts of the environment
• Organisms are adapted to their environment conditions

Competition

• Organisms compete for the same resources
• Competition occurs within species or between different species
• Plants compete for light, space, water and mineral ions
• Animals compete for space, food, water and mating partners

Interdependence

• Organisms in a community depend on each other for survival
• This includes food, shelter, and reproduction like pollination and seed dispersal
• Bird shelter in trees and bee pollination of trees are examples of this
• Removal/addition of a species affects populations by changing predator/prey numbers
• A stable community has balanced biotic/abiotic factors, where population sizes stay constant
• Tropical rainforests, oak woodlands, and coral reefs are examples of stable communities

Abiotic Factors

• An abiotic factor is a non-living factor
• Changes in abiotic factors affect the community

Light Intensity

• Affects photosynthesis
• Rate of photosynthesis affects plant growth
• Plants are food and shelter sources for organisms

Temperature

• Affects the rate of photosynthesis

Moisture Levels

• Plants and animals need water to survive.

Soil pH and Mineral Content

• Affects the rate of decay and how fast mineral ions are returned to the soil

Wind Intensity and Direction

• Affects transpiration rate (movement of water from root to leaves)
• Transpiration impacts plant temperature and photosynthesis through water/ion transport

Carbon Dioxide Levels

• Impacts photosynthesis rate
• Affects organism distribution by helping some thrive in high CO₂

Oxygen Levels for Aquatic Animals

• Varies more in water than in air
• Most fish need high levels

Biotic Factors

• A biotic factor is a living factor

Food Availability

• More food helps organisms breed and increases population

New Predators

• Introduces new consumers

New Pathogens

• Populations lack resistance, so they can get wiped out quickly

Competition

• A better-adapted species will outcompete others until other species numbers are too low to breed

Adaptations

• Enable survival in specific conditions

Structural Adaptations

• Affects shape or color of a part of the organism
• Carnivore sharp teeth tear meat
• Camouflage helps predators by helping them avoid detection
• Thick fat layers insulate species in cold environments

Behavioral Adaptations

• Affects the way an organism behaves
• Playing dead avoids predators
• Basking in the sun absorbs heat
• Courting attracts mates

Functional Adaptations

• Are involved in processes such as reproduction and metabolism
• Late implantation of embryos
• conserving water by producing little sweat

Extremophiles

• Bacteria lives in environments with extreme conditions like high temperature and pressure

Adaptations for Cold Climates

• Smaller surface area to volume ratio reduces heat loss

Adaptations for Dry Climates

• Kidney adaptations retain water producing concentrated urine
• Being active during cooler times
• Resting in shady areas

Plant Adaptations

• Include curled leaves, extensive roots, waxy cuticles, and water-storing tissue

Levels of Organisation

• Feeding relationships are shown by food chains

Producers

• Food chains begin with a producer
• Producers are photosynthetic organisms like plants or algae
• Glucose is used to create biological molecules which make up the biomass

Consumers

• Producers get eaten by primary consumers, transferring energy
• Primary consumers get eaten by secondary consumers
• Secondary consumers get eaten by tertiary consumers

Distribution and Abundance

• Species distribution/abundance gets worked out by using transects and quadrats
• This information gets processed calculating the mean, mode and median and then drawing a graph

Populations

• A stable one shows cycles between predators and prey
• More prey results in more predators
• More predators results in less prey
• Less prey results in less predators, allowing prey to increase again

Materials

• Recycled through an ecosystem
• Carbon and water cycles are vital for Earth's life

Carbon Cycle

• Plants and algae use carbon dioxide for photosynthesis to make carbohydrates, proteins, and fats, where they are then eaten
• Plants, algae, animals, and decomposers (microorganisms that break down dead material) all return carbon dioxide back into the air when they respire
• Wood/fossil fuels return CO₂ via combustion

Water Cycle

• The sun causes water evaporation from the seas and lakes, forming vapour
• Plants create water vapour through transpiration
• Water vapour condenses, forming clouds
• Precipitation returns water, running into lakes to provide water for animals
• Water runs into seas, restarting the cycle

Decomposition factors

• Temperature: reactions are faster in warmer environment, but too much heat denatures enzymes stopping it
• Water: microorganisms need water to grow, digest, and respire
• Oxygen availability: most decomposers respire aerobically

Compost

• It increases temperature and rate of decay

Methane Gas

• Microorganisms decompose waste anaerobically to produce gas, which is usable as a fuel

Biogas Generators

• Produce methane, requiring a consistent 30-degree temperature
• Can't be easily stored

Environmental Change Impact

• Alters species distribution inside ecosystems

Temperature

• Climate change forces insects to migrate to hotter areas

Water Availability

• Populations will migrate to find more water

Atmospheric Gas Composition

• Certain pollutants affect organism distribution, e.g., lichen and sulfur dioxide

Biodiversity

• The variety of different species of organisms on Earth or within an ecosystem

High Biodiversity

• Means there are more stable ecosystems
• Happens when species are less dependent on each other for food and shelter

Human Activities

• Have negative effect on biodiversity

Future of Humans

• Depends on maintaining biodiversity for food/medicines

Population Increase

• Due to our growing population, activities are increasing, and more resources and waste are being produced

Land Use

• More land is used for houses, which destroys animal habitats
• Pollution kills plants and animals through sewage, fertiliser, chemicals, smoke and land fill

Landfill

• Leaks toxic chemicals

Raw Materials

• We are using them up quicker than producing them

Impact Reduction

• We are trying to reduce our impact recently

Land taken up by humans

• Reduces quantity of animal habitats

Peat Bogs

• Accumulations where decomposition is slow due to acidity and waterlogging
• Peat bogs provide diverse habitats

Peat Bog Destruction

• For farming and fuel, releasing CO₂

Peat Replacement

• Slow formation is not keeping up with use

Deforestation

• Cutting down lots of trees in an area for other purposes

Tropical Areas

• Deforestations happens in tropical areas to provide land for cattle

Deforestation Problems

• Burning trees releases carbon dioxide
• Trees taking in CO₂, so less trees cause global warming

Global Warming

• Due to an increase in greenhouse gases, causing more heat to be absorbed and reflected
• Results in the rising temperature around the world

Effects of Temperature Increase

• Melting ice caps
• Rising sea levels
• Habitat loss
• Altered migration patterns causing extinction

Positive Human interactions

• Maintain rainforests, reduce water pollution
• Preserve scientific interests and replant habitats

Negative Human Interactions

• Production of greenhouse gasses leading to global warming
• Producing sulfur dioxide leading to acid rain

Biodiversity impact

• Breeding programs can stop extinction
• Protection of rare habitats, hedgerows, and field margins maintains biodiversity

Carbon Emission Reduction

• Reduces the rate of habitats being destroyed

Recycling

• Recycling reduces dumping waste into land fill, which reduces amount of land use

Trophic Levels

• They are the different stages of a food chain
• Level 1 organisms are called producers
• Level 2 organisms are called primary consumers
• Level 3 organisms are called secondary consumers
• Level 4 organisms are called tertiary consumers

Level 1 Organisms

• Plants and Algae are producers and produce their own food by photosynthesis

Level 2 Organisms

• Primary consumers are called herbivores and only eat plants

Level 3 Organisms

• Secondary consumers that eat herbivores are carnivores

Level 4 Organisms

• Tertiary consumers that eat other carnivores and are at the top of the food chain
• These organisms are called apex predators

Decomposers

• Break down plant/animal, by secreting enzymes
• Broken down matter moves into microorganisms through diffusion

Pyramids of Biomass

• Show relative biomass at each trophic level

Transfer of Biomass

• Shows the relative weights of material at each level Less biomass happens when you move up the trophic levels
• Not all food consumed is converted because the biomass of the level above is higher
• Producers transfer 1% of incident energy for photosynthesis

Biomass amount

• Only about 10% is passed to the next Trophic level
• The carnivores cannot eat bone
• Not all of the biomass eaten is converted into the animal eating it
• A lot of glucose is used in respiration, which produces the waste product Carbon Dioxide
• Urea gets released in urine
• There is undigested material in feces
• Herbivores don’t have all the enzymes to digest food

Food Security

• Having enough food to feed population

Factors

• Rising birth rates increasing the amount of food required
• Climate affects food through for example no rain
• Conflicts affect food through for example affect the availability of water

Sustainable Methods

• Are needed to feed everyone on Earth

Farming Techniques

• Used to increase energy (from food) that converts into biomass
• By reducing the animals transferring energy to the environment
• Raising them in small cages so they don’t move and waste energy for the small cages
• The areas where the animals are kept have high temperatures
• Growth with high protein
• Lots of animals are kept in distress and small cages because of it, which increases infection

Sustainable Fisheries

• Because fishing rate is faster than populations can regenerate, the number is decreasing
• Quotas and limits help species not disappear
• Net sizes restrictions have put in place
• Fishing quotas are in place, to prevent overfishing

Biotechnology

• Can be used to produce treatments/feed population
• Fusarium can produce mycoprotein, which is a vegetarian protein source grown on glucose syrup
• Genetically modified bacteria can produce insulin, which is purified to treat people with diabetes
• Resistant properties can increase yields and nutritional value

Explore ecological communities, competition for resources, and the interdependence of organisms. Learn how populations interact within habitats and the impact of species removal or addition on an ecosystem. Discover the factors that contribute to a stable community.