Ecology - Organisms and the Environment

Population

A population is a group of organisms of the same species living in the same place at the same time.

Community

A community includes all of the populations living in the same area at the same time.

Habitat

Place where an organism lives

Ecosystem

Interaction of a community of living organisms (biotic) with the non living (abiotic) parts of the environment

Competiton

Interaction between two or more organisms or species in which they all try to use the same limited resources

Interdependence

• Idea that all organisms in an ecosystem depend upon one another and there are countless complex relationships between them

• If one species is removed it can affect the whole ecosystem

Stable community

• Living and non-living components plus environmental factors of the ecosystem are balanced

• Population sizes that remain constant.

Four resources plants compete for

• Light

• Space

• Water

• Mineral ions

Five resources animal compete for

• Food

• Water

• Mates

• Shelter

• Territory (space)

Abiotic factors

Non-living factors that influence ecosystems

Abiotic Factor Examples

• Light intensity

• Temperature

• Water availability

• Soil pH

• Soil mineral content

• Wind intensity and direction

• Carbon dioxide concentration/levels for plants

• Water pH

• Oxygen concentration/levels for aquatic animals

• Moisture Level

Biotic Factor

Living factors that affect organisms in an ecosystem

Biotic Factor Examples

• New Predators arriving

• Competition - one species out competing another so numbers no longer sufficient to breed

• Availability of food

• New Pathogens /disease

Adaptation

Feature of an organism that increases its chance of survival and reproduction in a particular environment that they normally live in

3 Types of Adaptation

• Structural

• Functional

• Behavioural

Structural Adaptation

• Physical features of an organism that help them survive in the environment

• eg. white fur/ thick layer of blubber / large SA:V ratio / Protect body (quills)

Behaviourial Adaptation

• Way organism behave to help them survive in the environment

• eg. migration towards warmer climates / lizard sitting on hot rock to warm up

Functional Adaptation

• Process that take place within an organism to help them survive in the environment

• eg. less sweat produced and small amounts of conc urine (conserve water) + hibernation (slower metabolism conservers energy) + venomous snake producing venom to kill prey

Extremophile

An extremophile is an organism which lives in an extreme environment

• very high or low temperatures

• very high pressures

• very high salt concentrations

Food Chains

• Food chains show feeding relationships within communities, specifically the transfer of energy between trophic levels.

• All food chains begin with a producer which synthesises molecules

• Usually green plant/algae which makes glucose via photosynthesis (LIGHT)

Producers

Organism that can produce its own food molecules by photosynthesis

Consumer

Organisms that eat other organisms to get the food molecules (energy) they require

Primary consumer

• Organism that eats producers

• Herbivores

Secondary Consumer

• Organism that eats primary consumer

• Carnivores

Tertiary Consumer

• organisms that feed on secondary consumers

• fourth level of trophic chain carnivores

Predator - Prey Cycle

• Cyclical increase and decrease of predator and prey populations over time

• Stable community the numbers of predators will rise when prey numbers are high, then as prey numbers decline the predator numbers will also decline.

• Always out of phase with each other takes a while for one population to respond to changes

• Must be able to interpret graphs

Quadrat

A sqaure fram used to define a sample area in which the abundance and distribution of organisms can be measured

Investigatin distribution

• Investigate the effect of a factor on distribution of species how common an organism is in two sample areas

• Place 1m² quadrat on the ground at a random point within first sample area

• divide area into grid and use random number generator to generate coordinates

• count all organisms with the quadrat

• repeat steps 1 and 2 multiple times and take mean

• repeat steps 1-4 in second sample area

• compare mean mode meidan of data

Estimating Population Size

1. Mark out a line in the area you want to study usign a tape measure

2. collect data along the line

3. do this by counting organims youre interested in that touch the line

4. collect data by using quadrats

5. these can be placed next to each other along the line or at intervals

Percentage Cover

Percentage cover is often used to measure the abundance of a species where individual organisms are difficult to tell apart

Niche

Role of an organism within its ecosystem including its habitat its place in the food web and how it interacts with other species and the environment

Environmental changes what do they cause + Eg

• Distribution of organisms to change

• Change in distribution menas change in where organism lives

• Availability of Water

• Temp

• Composition of atmospheric gases

Water Cycle DRAW DIAGRAM

DRAW DIAGRAM

Nutrient Cycling

• Many different material cycle through abiotic/biotic components of an ecosystem

• Important that nutrient get recycled

• To provide the building blocks for future organisms

Water Cycle Steps

1. Water from lakes, rivers, oceans, and the soil, evaporates into water vapour, and rises into the atmosphere.

2. Water can also evaporate from plants in a process called transpiration.

3. As the water vapour accumulates it can condense to form clouds.

4. Later, the water will fall as rain, which we call precipitation.

5. The water will then seep into the soil, flow into rivers or lakes, and be taken up by plants. 

6. The whole cycle then repeats over and over. 

Percipitation

Liquid water falls from clouds as rain

Carbon Cycle DRaw

DRAW

Carbon Cycle Steps

• Powered by photosynthesis

• Ocean are a carbon sink increased acidication for co2 bleaches coral reefs and affects animals

• Removed from atmosphere by green plants and algae made used to make glucose

• Turned into carbs,fats,proteins which make up bodies of plants

• Carbon becomes part of animals when plants eaten

• Detritus feeders + microorganisms feed of dead organisms waste is also broken down

• Carbon returned through the air via respiration, industrilasation

Decomposition

Process by which dead organic matter is broken down into simpler organic or inorganic substances eg.co2 minerals

Decomposeres

• Bacteria and Fungi

• Microscopic single cellular

• Present at all trophic levels

• Produces extra cellular enzymes (all enzymes create polymers—> into monomers)

• Nutrients absorbed by diffusion

• Produce ammonium ions and release other ions

• Respire releases co2 and water but release of energy allows atp to happen

Factors affecting rate of decay

• Temperature

• Oxygen Availability

• Water availability (mositure)

• No. of decay organisms

Oxygen - Decay

• More oxygen

• More aerobic respiration

• More energy available

• Faster growth and decomposition

Temp - Decay

• Higher temperature

• Particles have more kinetic energy and enzymes are closer to potimum temp

• higher rate of reactions

• more decomposition

• however it will denature enzymes if temp too high decreasing rate

Water - Decay

Decomposers need water to survive so decomposition increases in moist conditions

• Waterlogged soil means water filled all the air gaps

• Less oxygen due to less air

• less aerobic respiration meaning fewer chemical reactions thus slower decomposition

Compost

• Decomposed orgnaic matter used as natural fertiliser

• Recycles nutrients back into souil

• Creates ideal conditions for decay

Biogas generator + DRAW

• Large containers (fermenters) in which animal or plant waste is left to decay anaerobically

Batch generator

• Small batches

• Manually loaded up withg waste

• By products cleared at the end

• Dont produce at steady rate

Continuuous generators

• Waste continuously fed in and biogas is produced at a steady rate

In order to supply and reproduce what do organisms require?

• Organisms require a supply of materials from the surroundings

• And from other living organsims there

Bacteria - Extremeophile

• adapted to live in extreme conditions

• like super hot volcanic vents

• very salt lakes

• high pressure on the sea bed

What type of organisms are Extremophiles?

• Bacteria and Archea

What happens to glucose made by photosynthesis?

• Used in metabolic reactions

• To make other biological molecules of the plant

• Plants biomass (mass of living material)

• Though of as energy stored in a plant

Predator

A predator is an animal that hunts and kills other animals for food

What happens to most of the energy as it passes along a food chain?

Most of the energy is lost to the surroundings

Prey

Animals that is hunted and killed by other animals for food

What is sampling?

• Method of studying a population in which only a subset of the organisms are measured

• the subset is then used to make predictions about the whole population

Why is sampling used?

• allows scientists to draw conclusions without using so much time and effort

Transects

• Used to observe and record changes in species across different areas of a habitat

• They study distribution NOT abundance

How are quadrats used with transects?

Quadrats are placed at regular intervals along a transect line to measure species distribution

Why should multiple transect lines be used?

• makes the data more representative of the entire study area

What might affect the distribution of dandelions on a field?

• Factors

• eg. soil quality/moisture/proximity to lake or woodland

What does abundance and distribution mean?

• Abundance → Refers to how many organisms there are

• Distribution → Refers to where the organisms are

What organisms produce biomass on earth?

• Photosynthetic organisms

• eg. Algae and Plants

What does carbon cycle do?

• returns carbon from organisms to the atmosphere as carbon dioxide to be used by plants in photosynthesis

What does water cycle do?

provides fresh water for plants and animals on land before draining into the seas. Water is continuously evaporated and precipitated

What process remove CO2 from the atmosphere?

Photosynthesis

Which 3 Process release Co2 into atmosphere?

• respiration

• Decomposition (microbial respiration)

• Combustion

What are the role of microorganisms?

• cycling materials through an ecosystem

• by returning carbon to the atmosphere as carbon dioxide

• and mineral ions to the soil

Difference between detritus feeder/decomposers

• DF →