ESS SL - Semester 1 Term 1 - 2.1-2.4

What is Ecology?

Study of the living and non-living parts that interact within an ecosystem.

What are Abiotic Factors?

Non living, physical factors in the ecosystem that may influence an organism or a system.

What are the examples of abiotic factors?

• Sunlight influences temperature and evaporation rates, which also influences precipitation levels.

• Temp

• Water

• All these abiotic factors are interdependent.

What are the major biotic and abiotic components of an ecosystem?

• Precipitation

• Oxygen

• Carbon Dioxide

• Producer

• Decomposers

• Water

• Soluble mineral nutrient

• Secondary Consumer

Ecosystem

A community of interdependent organisms and the interactions with the physical environment in which they live.

What are the different levels of organization?

• Species

• Population

• Community

• Ecosystem

• Biome

• Biosphere

What is an ecosystem?

• A community of interdependent organisms and the interactions with the physical environment in which they live. Or, The abiotic and biotic factors and the interactions between them.

What is the key of an ecosystem?

The interaction between organisms and environment

What’s a species?

A group of the same type of organisms that is able to reproduce and produce fertile offspring.

What are scientific names?

They are used by scientists to identify a specific species.

How many parts does scientific names contain?

It contains two parts: Genus Species

What are the characteristics of Scientific Names?

• It contains two parts: Genus Species

• Always underlined, or in italics

• Genus always capitalizes & species all lower case

What are keystone species?

Species that are crucial to the maintenance of their ecosystem

What’s vital in determining the nature and structure of the entire ecosystem?

Keystone species

What’s a habitat?

Where an organism lives

What should a habitat provide for its living organisms?

It should provide:

• Food

• Water

• Shelter

What’s a niche?

Where, who, what and how an organism lives.

A niche ranges from what-to-what?

It ranges from unidimensional space to a multidimensional space.

What does a niche include?

• Space utilisation

• Food consumption

• Temperature range

• Moisture requirements

A niche should not?

• Have two identical or similar niches (bc they cant live in the same habitat)

• No two species can have the same ecological niche in the same place at the same time.

What’s fundamental niche?

The entire range of conditions in which a species could live.

What’s realized niche?

The actual conditions under which the species lives (usually due to competition)

Case Study: Joseph Connell’s barnacles

• Both of these barnacle species could live anywhere between the high tide and low tide lines-their fundamental niche.

• But abiotic environmental conditions and competition for resources (a biotic factor) limit the size of each species-realized niche.

What are the Characteristics of a population?

• Able to interbreed

• Populations can be separated by geography eventually stopping interbreeding

• Formation of a new species

Predation equals to?

Hunting

Herbivory equals to?

Hunting plants

What’s parasitism?

One species depends on another for nutrition, harming the host organism in the process.

What does mutualism equal to?

It’s when two species benefit from one another

What are the 2 types of competition?

Intraspecific, and interspecific.

What’s competition?

Fighting for the same resources

What’s Amensalism?

One unaffected the other harmed

What’s Neutralism?

Two organisms do not affect each other. No relationship.

What’s population Dynamics?

The study of the change in populations over time.

What would happen when there’s no limiting factors?

It will result in exponential growth (there is nothing limiting population size).

What happens during the ‘Exponential Growth Phase’?

the ecosystem provides its species/ living organisms with abundant food, space, and light

What happens during the ‘Transitional Phase’?

Competition

What happens during the ‘Plateau Phase’?

When population reaches carrying capacity (K) there is no longer growth.

What’s Carrying Capacity?

The maximum number of organisms of a single species that an ecosystem can support.

What are limiting factors?

Factors in an ecosystem that limit the population size if there are too much or too little for it.

What does limiting factor cause?

It causes a reduction in population growth as they become short in supply for resources.

What’s density dependent factors?

It increases or decreases the carrying capacity of a population based on the size of the population.

Carrying Capacity K and r Strategists

Plotting the growth of a population from an initial growth realization factor of 1 to a final factor of 0 produces a curve like this, called the logistic growth curve or S-shaped curve of growth.

Case Study: Reindeer on St Matthew Island

• Small island in the Bering Sea

• Reindeer (Rangifer tarandus) introduced in 1944, increased from 29 to k in 1963.

• Crash die-off the following winter to less than 50.

Community

A group if interacting species, living in the same ecosystem

Population

All he individuals of the same species in a community

Individual

A single organism of one species

Ecosystems and Communities are part of a bigger…?

Ecological organisational structure

Photosynthesis and respiration can be viewed as systems, which means?

they have inputs processes and outputs.

It is important to remember that producers (autotrophs) undergo…?

photosynthesis and respiration simultaneously, while consumers (heterotrophs) only respire.

Respiration

Oxidation of glucose to release energy, then used in all activities in the organism.

How energy is formed

Energy is stored in chemical bonds of glucose, and as the glucose is broken down the energy released is used to create another chemical, which our cells can readily use.

Respiration in word equation

Glucose + Oxygen → Carbon dioxide + water

Photosynthesis in word equation

Carbon Dioxide + Water yields glucose + Oxygen

Trophic level

Position an organism occupies in the food chain

What does T1 in model trophic levels mean

Producer

What does T4 or T5 in model trophic levels mean

terrestrial ecosystem T4 is the highest due to losses of energy between trophic levels.

Producers (Autotrophs)

Plants or algae that produce their own food using photosynthesis and form the first trophic level in a food chain.

Chemosynthetic Organisms

Produce food without sunlight

Feeding relationships involve

Producers, consumers, and decomposers.

Models to illustrate feed relationships

1. Food chains

2. Food webs

3. Ecological Pyramids

Food chain

Linear sequence of organisms through which nutrients and energy pass as one organism, and eats another.

Pros of food web

it shows all of the relationship between all organisms in a community, and it shows how different food chains interact withe achother, and overlap.

Ecological pyramid

Graphical representation designed to show the biomass or bio productivity at each trophic level in a given ecosystem.

3 types of ecological pyramids

1. Pyramid of energy

2. Pyramid of Biomass

3. Pyramid of numbers

Pros of Ecological pyramid

Quantitative models to show information about the organisms at each trophic level.

Pyramid of numbers

numbers of organisms

pyramid biomass

mass of organic matter

pyramid of productivity

flow of biomass or energy overtime

Pros of pyramid of numbers

1. Simple overview of community structure

2. Non-destructive method

3. Useful in comparing changes in a number of individuals over time

Weakness of pyramid of numbers

1. All organisms included (regardless of size)

2. Numbers can be too great to represent accurately

3. Some animals feed at more than one trophic level (omnivore)

pyramid of biomass (definition)

standing stock/ storage of each trophic level, measured in units (grams of biomass per square meter), or Joules per square meter)

pyramid of biomass calculates

dry mass and energy content

Pyramid of biomass represents

standing stock

pyramids of biomass can show greater quantities at higher trophic levels because

they represent the biomass present at a fixed point in time, though seasonal variations may be marked.

pyramid of biomass inverted

occurs w aquatic ecosystems when growth is rapid, and seasonal.

strength of pyramid of biomass

overcome the issue of counting seen in PN

limits of pyramid of biomass

1. seasonal variation

2. destructive and unethical

3. not all organisms have the same calorific value

pyramid of productivity

flow of energy through a trophic level, indicating the rate at which that storage is being generated.

pyramid of productivity shows

turnover of biomass at each trophic level

the clue that you need to find when dealing with pyramid of productivity loss is…?

time

pyramid of productivity for entire ecosystems over a year always shows…?

a decrease along the food chain

strengths of pyramid of biomass

1. Most accurate, because they show actual energy available.

2. Ecosystems can be compared

3. Solar input can be added.

Limits of pyramid of biomass

1. Difficult data collection

2. Species can be difficult to assignment to particular trophic level

Pyramid of productivity in a healthy ecosystem will form a…?

pyramid shape, due to the 10% rule and energy efficiency.

Why are the pyramids more narrow towards the apex?

Due to the tendency for numbers of biomass and energy to decrease along food chains.

Biomagnification

Increase in concentration of non-biodegradable pollutants along a food chain.

Toxins

poisonous materials

Persistent chemicals/ toxins/ nonbiodegradable pollutants

Unable to breakdown in the organism/trophic level, so it stays.

Dangers of Biomagnification

it accumulates in the food chain, and damage organisms (Especially the predators).

Toxins that cause problems in the food chain

heavy metals, and organic pollutants

Bioaccumulation

Inc in concentration of persistent or non-biodegradable pollutants along a food chain.

Toxins (eg. DDT, and mercury) accumulate along the food chains due to…?

Decrease of biomass and energy

Similarities of Biomagnification, and Bioaccumulation

1. Toxins are ingested

2. Bioaccumulation may lead to biomagnification

3. Concentration inc overtime

Difference in Biomagnification, and Bioaccumulation

1. Biomagnification: Accumulation with an organism, & Toxins are ingested at a higher rate than they are eliminated.

2. Bioaccumulation: Organisms (at higher rank), are more at risk, &Inc in concentration of a toxin as it moves from one trophic level to the next.

what animals are most susceptible to changes in the environment?

Apex predator, or top carnivore.

Case Study: Minamata Bay

• Minamata a small town in Japan, was polluted by mercury and methylmercury from a factory known as Chisso (a factory that produces fertilizers and plastics). This caused the Minamata citizens to have a neurological disease.

what happens during insolation?

Solar radiation enters the earth, they become unavailable for ecosystems bc its absorbed by inorganic matter or reflected back into the atmosphere.

Albedo

Reflectivity of a surface

Albedo (dark colors)

Low albedo

Albedo (Light colors)

high albedo