Biology Unit 7 Ecology

1. Define: biosphere, biome, ecosystem, habitat, community, population.

2. List biotic and abiotic factors that affect the distribution of organisms. 

3. Define and give examples of symbiotic relationships: mutualism, commensalism, parasitism.

4. Describe and explain the flow of energy through ecosystems.

5. Draw and interpret: food chains, food webs, and pyramids of numbers, biomass and energy. 

6. Describe the energy losses between trophic levels and their implications for the length of food chains

7. Describe and explain factors that may cause changes in population, e.g. predator-prey interactions. 

8. Describe the threats to biodiversity and the benefits of maintaining biodiversity.

Lo.. 1 define: Biosphere, Biome, ecosystem, habitat, community, population

Meaning of ecology:

The relationship between organisms and their environment

Biosphere:

All areas with living things on the planet

Ecosystem:

community interacting organisms and their physical environment.

Community:

Many individuals of different species live in the same place

Organism:

1 individual(1 member of a species)

Terrestrial Biomes:

Tundra:

Cold temperature, animals migrate during winters, dominated by slow frowin gvegetation, soil is frozen (permafrost)

Grass Lands:

Overall low to moderate rainfall(seasonal drought), Fertile soils, dominated by grasses

Examples: prairies, steppes, savannah

Coniferous forest:

Long cold winters, evergreen tress, short warm winters, some animals hibernate, poor soil.

Desert:

Driest Biome(lack of water), often hot with varitation in temperature during the day(sometimes cold), plants display adaptations to conserve water

Deciduous Forest:

High rainfall with no dry season, moderate temperature, Dominated by broad leaved trees

Tropical rain forest:

High temp, little seasonal variation, high rainfall no dry season, Dominated by large trees, highest biodiversity, plants grow very fast but usually soils arent fertile.

More looking at Land Biomes of the World

More desserts are found closer to the tropial o fcancer, further north has more tundra, southern areas below the equator had more tropical areas.

2 Key factors determining Biomes:

Climate determines the biome based on how much sunlight recieved

and the amount of rainfall also determines the biome.

Lo2. List Biotic and Abiotic factors that affect the distribution of organisms

Organisms are affected by both Biotic and Abiotic factors.

Abiotic meaning:

NOn living

Examples such as cement, rocks, dirt, mud, wind, cloud, sun.

Abiotic factors for a tree would be things such as Co2 levels, ight intensity, water in the soil, and temperature, fertilizers, and wind.

For Fish Abiotic factors would be

• Water pollution(chemicals and plastic)

• Currents

• Salt level(salinity)

Biotic meaning:

Living

Examples: Plants, animals, insects, parasites, protists, predators

Biotic factors for insects

• Pollinators

• pests

• habitats

Lo. 3 Define and give exapmles of symbiotic relationships, mutualism, commensualism, nand parasitism.

Three types of symbiotic relationship:

1. Mutualism: where both organisms benefit

2. Commensalism: only one organism benefits while the other is unaffected/unharmed

3. Parasitism: One organism benefits while the other is harmed. It is usually a parasite feeding on the host

Predator-Prey Relationships

• Predation is a biological interaction where one organism hunts(predator) and feeds on another(prey)

• Herbivory is a form of predation in which the prey organism is a plant.

Competition:

• Competition describes an interaction between 2 organisms that harms both. (cannot coexist in the same habitat as they are competing for the same resources)

• Intraspecific competition occurs between members of the same species

• Interspecific competition is competition between members of different species.

Walruses:

• Mates

• Territory

• Mates

  Intra-specific

Trees:

• Sunlight

• Minerals

  interspecific

Lo. 4 Describe and explain the flow of energy through ecosystems

Autotrophs: Make their own food molecules from simple substances (CO2, etc) Examples: photosynthesis from sunlight

Because autotrophs synthesize their own organic molecules, they are called Producers.

Heterotrophs:

Obtain food molecules from other organisms. Heterotrophs cannot produce their own organic molecules and get their food from other organisms so they are called Consumers

Types of Heterotrophs

• Herbivores - consumers mostly feeding on plant matter (eg. Sheep, rabbits, cows)

• Carnivores are consumers that feed mainly on animal matter (lions, wolves, crocodiles)

• Omnivores are consumers that have a diet of both plant and animal matter (pandas, humans)

2. Scavengers- Mainly feed on dead and decaying animals, bodies rather than live prey:

   Examples Include Hyenas, vultures, and crows.

3. Detritivores are a type of heterotroph that obtains nutrients from nonliving organisms

   • Detritus is dead organic matter (fecal matter)

   • Humus specifically means the decay of leaf litter

   • Detritivores include dung beetles, earthworms, woodlice, snails, crabs

   • They help with the decomposition

4. Saprotrophs

Live on or in non-living organic matter, secrete digestive enzymes into it and absrobing the products of digestion

• Examples of saprotrophs include bacteria and fungi (Decomposer)

Two processes essential to ecosystem function are energy flow and chemical cycling. Example of this would be the mitochondria of eukaryotic cells use the products of photosynthesis as fuel for cellular respiration.

Lo. 5 Draw and interpret: food chains, food webs, and pyramids of numbers, biomass and energy

What is a food chain> LInear feeding relationship between species

• Arrows represent the transfer of energy and matter as one organism is eaten by another (energy flow direction)

• The first organism is always the producer, followed by consumers

Examples of food chains in different habitats:

• Producer (carrot plant) → 1st consumer (rabbit) -→ 2nd consumer(feral cat) → 3rd consumer (red fox)

Marine food chain:

• Producer (bacteria) → 1st consumer (shrimp) → 2nd (atlantic) → 3rd (grey seal) consumer

Food web:

A diagram that shows how food chains are linked together into more complex feeding relationships.

• Organisms can have more than 1 food source

• Organisms can have more than 1 predator

Example of one food chain would be

Algae→ prawn→ trout

The effects of a decrease in prawn population will effect what?

• The trout population will decrease(less food)

• More algae

There are 3 ways to show information of each trophic level.

Examples of ecological pyramids for a specific food chain:

1. Pyramid of numbers: A pyramid of numbers shows the number of individuals at each level of the food chain.

Biomass can be lost between the stages because not all matter eaten can be digested and some is excreted in waste such: feces, sweat , hair, bones. feathers

Pyramid of energy: A pyramid of energy shows the total amount of energy of all individuals at each level of the food chain. A lot of the energy is lost between levels.

Each level is only 10% efficient (transferred) meaning 90% of energy is lost from respiration and heat.

Lo 6. Describe the energy losses between trophic levels and their implications for length of food chains and for feeding the growing human population.

Since energy and biomass is lost between each level of a food chain, the number of potential trophic levels are limited. Higher trophic levels receive less energy and biomass and need to eat larger quantities to obtain sufficient amounts.

Question

why is Meat-Free Mondays good for the planet

• Less energy is being lost from the food chain n

• reduces the amount of CO2 in the air as there is a reduction in airplane usage

Question 2

Which farm could feed the most people, a farm growing just vegetables, or a farm raising beef cattle on grass grown on the farm?

• Just vegetables because it would use up less energy, as it is from vegetables → humans

• whereas if it were cows, the food chain would be grass→ cows → Humans

• meaning more energy loss

Lo. 7 Describe and explain factors that may cause changes in population

Limiting factors

• Limiting factors are environmental conditions that determine the rate of population growth occurring

Biotic factor: Disease, predation, competition

Abiotic factors: food, water, temperature, Space, sunlight(light intensity)

Predator-prey interactions

• A biological interaction where 1 organism hunts and feeds on the other

• Because the predator relies on the prey as food, their populations are intertwined

It is a loop where populations rise and fall

Example:

Rabbits increase 1 year due to more grass availability -→ Gradually more foxes since there’s more food→ More rabbits eaten → Lower rabbits → lower foxes → then higher rabbits again

lo. 8 Describe the threats to biodiversity and the benefits of maintaining biodiversity

Threats to Biodiversity:

1. Habitat destruction and fragmentation

2. Invasive species

3. hunting(poaching), Collecting and harvesting

4. Pollution (air and water)

Biodiversity

• The term biodiversity refers to the variety of living organisms on the planet

  Some parts have greater biodiversity. For example, the arctic Tundra has a lower biodiversity than a. tropical rain forest.

What is an endemic species

• Native to a certain place

Whenever a species disappears it weakens the gene pools as it disrupts the entire system as all organisms are intertwined. Even taking 1 component away can hurt the entire system.

Example: coral reeds → organisms depend on coral for micro habitats and shelter→ fungi and bacteria → The coral is the loom and allows habitat and life for other organisms

Importance of biodiversity:

These 3 main features influence the difference between a strong and weak habitat:

1. Ecosystem

2. Species

3. Genetic

The more intertwined they are, the more resilient they are

Determining the nine categories of risks for animals:

EX (extinct)

2. EW (extinct in the wild)

3. CR (critically endangered)

4. EN (very highly endangered)

5. VU (vulnerable)

6. NT (near threat)

7. Least concern(LC)

8. Data Deficient (DD)

9. NE (not evaluating)

The value of biodiversity

Practical and economic value:

• Provides resources (food, med, clothing, raw materials)

• Water purification.

• Soil fertility

Aesthetic value

• Everything will look dull

• natural beauty

• Tourism

Moral value

• Protecting all species equally

• Responsibility to protect future generations

• religious beliefs

Methods of preserving biodiversity

Habitat protection

• National parks

• limiting pollution

• Zoos and botanical gardens