IB Biology (Option c - Ecology and Conservation)

Abiotic Factors

Caused by non-living organisms

Biotic Factors

Caused by living organisms

Abiotic factors that affect distribution in plants

Temperature, water, light, soil pH, salinity and mineral nutrients

Biotic factors that affect distribution in plants

Competition, herbivory (consumers eating them), predators, parasites, humans

Abiotic factors that affect distribution in animals

Temperature, water, breeding sites, food supply and territory

Sample

Part of a population, area, or some whole thing, chosen to illustrate the population, area, or specific thing

Random sampling

Counting numbers in small, randomly located parts of total area (using quadrats).

Factors that affect random sampling

Number of samples, position of samples, and size of sample area

Lincoln Index (population size formula)

(# of marked x (average) # recaught) / (average) # recaught that were marked

Herbivory

Primary consumers feed only on plant materials. Primary consumers can be considered predators of plants. The relationship can be beneficial or harmful for the plants.

Predation

A consumer kills and eats another consumer. Predator evolved and adapted to optimize killing (finding, chasing, catching, killing, eating, digesting).

Intra-specific competition

Where one or more individuals of the same species depend on the same resource and competition arises.

Parasitism

derives nutrition from a host. can weaken or kill host. Uses host as habitat.

Mutualism

both organisms in this relationship receive a bennifit. Often help organisms obtain food or avoid predation.

Inter-specific competition

Where one or more individuals of different species depend on the same resource and competition arises.

Niche

A niche is a specialized habitat of an organism including space, territory, nutrition, feeding habits, interactions and relationships with other organisms, reproductive habits, role and impacts in the habitat and ecosystem. One species or population can occupy the same niche for extended time.

Fundamental niches

the potential mode of existence, given the adaptations of the species (where it COULD live)

Realized niches

the actual mode of existence, which results from its adaptations and competition with other species (where it ACTUALLY lives)

Competitive Exclusion

states that if two species are competing, the species that uses the resource more efficiently will eventually eliminate the other locally- no two species can have the same niche

Function of a transect

They can be used to correlate the distribution of a species with an abiotic variable. Used to estimate species distribution over a set distance and in correlation with abiotic variables.

Biomass

dry weight of organic matter of a group of organisms found in a habitat

Species

a group of organisms that can interbreed and produce fertile offspring

Habitat

the enviornment in which a species normally lives or the location of a living organism

Population

a group of organisims of the same species qho live in the same area at the same time

Community

a group of populations living and interacting ith eachother in the same area

Ecosystem

a community and its abiotic enviornment

Ecology

the study of relationships between living organisms and their environment

Autotroph

an organism that synthesises its organic molecules from simple inorganic substances (e.g. trees, plants, algae)

Heterotroph

an organism that obtains organic molecules from other organisms (three types; consumer, detritivore, saprotroph)

Consumer

obtain nutrients from other living organisms

Detritivore

an organism that ingests non-living organic matter (e.g. earthworms, vultures)

Decomposers

obtains nutrients from dead organic matter

Saprotroph

an organism that lives on or in non-living organic matter, secreting digestive enzymes into it and absorbing the products of digestion (e.g. mushrooms, bacteria)

Food Chain

a linked feeding series; in an ecosystem the sequence of organisms through which energy and materials are transferred in the form of food from one trophic level to another.

Food web

a diagram that shows how energy moves from one organism to another in an ecosystem. (non-linear and branching)

Trophic level

the level of the food chain at which an organism is found.

producer -> primary consumer -> secondary consumer -> tertiary consumer

Light

the initial (beginning) energy source for almost all communities

Exponential Phase

With low or reduced limiting factors the population expands exponentially into the habitat

Transition Stage

Resources are reduced and become limiting in the growth of the population

Population plateau

is where the population remains constant over time/ generations

Population Size

Natality - Mortality + Immigration - Emigration

Quadrant

you take samples from a quadrant (usually 1m by 1m) the multiply to get the size of the place you are measuring

Transect

use string across a place where you collect data, collect the data of whatever passes the string

Niche (basic answer)

Organism's food(trophic level), habitat and activity pattern(when it is active)

Competition

members of different species try to use a resource that is limited in supply

Gross Production

total amount of organic material produced by plants in an ecosystem. (measured in kilojoules)

Net Production

energy able to be passed on by producers/ consumers. Limited by loss of energy due to cellular respiraton.

Gross Production (formula)

plant respiration + net production

Net Production (formula)

gross production - plant respiration

Ecological Succession

a series of changes to a species in an ecosystem caused by complex interactions between the community of living organisms and the abiotic environment. it is the process by which communities in a particular area change over time

Process of ecological succession

lichen -> moss -> ferns -> flowering plants -> conifers

Primary Succession

starts in an environment where living organisms have not previously existed (e.g. where a region has been extinguished by a volcanic eruption, like Krakatoa on the Indonesian Island, 1883)

Secondary Succession

takes places after a land clearance like a fire or a landslide. does not involve loss of soil so changes tend to be quicker than primary succession.

Climax Community

the stable 'culminating' community developed after ecological succession (even if it continues to change for hundreds of years after)

Changes to environment during ecological succession

- amount of organic matter increases
- soil becomes deeper
- soil structure improves
- amounts of mineral recycling increases

Roots effecting succession

- As plants grow, roots grow deeper down and break rocks into small particles which helps with soil formation.
- roots hold soil particles together, preventing soil erosion
- presence of root and root hair helps in retention of water and slows down drainage

Plants effecting succession

- plants enrich the soil with minerals as they die and decompose
- water that evaporates from plant leaves condenses and comes down as rain

Biome

group of ecosystems that have the same climate and dominant communities. Categorised by temp, rainfall and plant species

Biosphere

narrow belt of the earth from bottom of the ocean to the atmosphere, where organisims can live

Desert Biome

Low rainfall, warm to very hot days and cold nights. Very few plants, some storing water and some growing quickly after rain.

Grassland Biome

Low rainfall, warm or hot summers, cold winters. Dominated by grasses and other plants than can withstand grazing.

Shrub-Land Biome

Cool wet winters, hot dry summers often with fires. Dominated by drought-resistant shrubs, often with evergreen foliage

Temperature Deciduous Forest Biome

Moderate rainfall, warm summers and cool winters. Dominated by trees that shed their leaves in winter with shrubs and herbs underneath

Tropical Forest Biome

High to very high rainfall, hot or very hot in all seasons. Huge diversity of plants

Tundra Biome

Very low temperatures, very little rainfall, mostly as snow. Very small trees, a few herbs, mosses and lichens.

Biodiversity

diversity of ecosystems on earth, the diversity of species within them, and the genetic diversity of each species.

Reasons to converse a biodiversity

- extinct species cannot be brought back
- loss of habitat can effect other areas
- ethical; do we have a right to destroy it?
- may contain unknown but valuable species (medicine)
- reduction of biodiversity (trees) can increase rate of erosion
- remove sources of life/food/income from indigenous people
- aesthetics
- loss of tourism
- destruction of species' habitats
- trees absorb CO2 and help minimize global warming

Simpsons Diversity index

( N-(N-1) ) / ( total n (n-1) )

N = total number of organisms
n = number of individuals of each species

Biomagnification

process by which chemical substances/toxins are ingested through a food chain and become more concentrated at each trophic level.

Pyramids of Energy

Shows the energy flow through each trophic level of an ecosystem.

Explain the small biomass and low numbers of organisms in higher trophic levels

There is a decreasing biomass of organisms in higher trophic levels because energy is lost between levels in the form of heat (respiration), waste, and dead material. Around 10-20% of energy proceeds to the next trophic level.

Constructing a pyramid of energy

The lowest bar of a pyramid of energy represents gross productivity. The next bar is the energy ingested as food by primary consumers. The next bar is the energy ingested as food by secondary consumers. The arrows demonstrate the direction of energy flow. The units are energy per unit area per time.

Alien species

type of species that humans have introduced to an area where it does not naturally occur

Biological control

when another alien specie is introduced to eliminate / control the other (e.g. the mongoose was introduced to Hawaii to control rats. unfortunately, the mongoose also eats other native Hawaiian animals)

Example of Predation (Alien Species)

e.g. The Brown Tree Snake, originating in the South Pacific and Australia, has eaten/extirpated 10 of 13 native bird species, 6 of 12 native lizard species, and 2 of 3 bat species on the island of Guam.

Organic Matter

starch (stored energy), proteins & structural molecules. a lot of stored energy and nutrients are used by each individual

Loss of energy between trophic levels

Around 90% of energy is lost between trophic levels through
- not ingested (eaten)
- not digested
- excreted
- lost as heat from respiration

Example of Extinction (Alien Species)

e.g. The fungus (ophiostoma ulmi, the pathogen that causes Dutch elm disease) and the bark beetle (which carries the pathogen) were introduced to the US from Europe on infected wood. The combination of the two has caused the destruction of millions of elm trees.

Impact of Invasive Species in Inter-Specific Competition

'aliens' outcompete native species for resources, such as food, space, or light. Native species may be forced out of their niches.

Impact of Invasive Species in Predation

'aliens' are predators of other native species. Prey species numbers decline rapidly as they cannot adapt to new predator

Effects of ultraviolet (UV) radiation on living tissues and biological productivity

- UV promotes DNA damage (mutations, cancers or tumors)
- damages organic material (enzymes may not function, loss of productivity in autotrophs, crop failure)
- human health impacts (cancers/skin cancer, catarcs and eye damage, depressed immune function, food shortage because of crop failure)

Effect of chlorofluorocarbons (CFCs) on the ozone layer

There is a natural balance of ozone creation and destruction due to UV radiation in the atmosphere. The ozone layer is maintained at safe levels. When CFC's are released into the atmosphere they speed the depletion of the ozone layer.

Effect of chlorofluorocarbons (CFCs) on the ozone layer step by step

1- UV radiation splits CFC molecules.
2- This releases chlorine molecules.
3- Chlorine splits ozone molecules into O2 and chlorine monoxide.
4- Chlorine then binds free oxygen atoms and is released.
5- Chlorine goes on to split more ozone molecules. It can split up to 10,000 molecules. At that rate, the natural ozone production cannot compensate.

How TEMPERATURE effects PLANT distribution

- Higher temperatures denature enzymes, retard growth of plants, increase of transpiration
- Low temperatures decrease enzyme activity
- Freezing temperatures inactivate enzymes
- frost-resitant crops

How WATER effects PLANT distribution

- Needed for enzyme activity, transport, photosynthesis, support and more
- Low diversity of plants in deserts and polar regions

Xerophytes

plants (such as cacti) that can survive in low-water conditions

Hydrophytes

plants (such as rice) that survive in water logged soil or clay

How LIGHT effects PLANT distribution

Light is important for photosynthesis and flowering. Dark areas have small numbers of plants

How SOIL PH effects PLANT distribution

Soil pH is important for absorption of nutrients. If soil is acidic, desertification (fertile -> desert) can occur. (Limestone can neutralize soil)

Calcifuge Plants

plants the survive in low soil pH (blueberries and cranberries

Clay-Soil Plants

plants that survive in high soil pH (rice)

How SALINITY effects PLANT distribution

- Salinity has effect on the absorption through osmosis
- High salinity causes plants to lose water (through osmosis)

Halophytes

plants that live in highly saline (salty) soil

How MINERAL NUTRIENTS effects PLANT distribution

- Needed for many vital functions
- NITROGEN: needed to manufacture proteins, enzymes, nucleotides, vitamins and other compounds
- PHOSPHOROUS: used in the formation of phospholipid and other strucutres
- availability of minerals determine distribution of plants

How TEMPERATURE effects ANIMAL distribution

- affects the concentration of animals
- only specially adapted animals can live in extreme temperatures
- all animals are adapted to surviving in a narrow range of temperatures

Ectotherms

'cold-blooded' animals that rely on external temperatures for metabolism

Endotherms

'warm-blooded' animals that rely on external temperatures for metabolism

How WATER effects ANIMAL distribution

- as a habitat (aquatic animals)
- as a place to lay eggs (mosquitoes)
- source of oxygen (gills, fish)
- heating / cooling
- drinking
- source of food
- transport medium

How BREEDING SITES effects ANIMAL distribution

- needed for growth and protection of young
- some need specific areas to breed (mosquitoes need stagnant water to lay eggs)
- many species need a special type of site and can only live where these sites are available
- specific temperatures
- dark protected areas

How FOOD SUPPLY effects ANIMAL distribution

- plant distribution
- seasonal sources of energy
- energy storage (hibernation)
- acceptable food sources may be narrow ranged (pandas and bamboo)
- some can only live in areas where food supply is obtainable
- animals are heterotrophs