N5 BIO life on earth

Biodiversity

variety of life within an area

ecosystem

consists of all organisms living in a particular area and the non living parts which the organisms interact

habitat

the place where an animal lives

Population

total number of one type of organism

community

all the organisms living in the ecosystem

Species

group of organisms that can produce fertile offspring

niche

the role an organism plays within a community, including the use makes of the resources and it's interactions with other animals

food chain

diagram that displays the flow of energy in an ecosystem

food web

interconnected food chainsshows flow of energy in an ecosystem

role of organism can be affected by

competition, resources, predation, environmental conditions

plants make energy by

photosynthesis

How is energy lost in a food chain?

Body heat, movement, undigested foods/feces, growth

how can pyramids be irregular

-fewer large producers
-infestation of parasites feeding on one large animal

animals compete for

-habitat
-mates
-food
-territory

plants compete for

space, sunlight,water,oxygen,soil nutrients, carbon dioxide

interspecific competition

members of different species compete for similar resources (less intense)

intraspecific competition

competition between members of the same species(more intense)

why is it important biodiversity is maintained

biodiversity is important because it provides food + medicines and keeps ecosystems stable

abundance

relative quantity of organisms present

distribution

the spread of an organism throughout the ecosystem

factors affecting biodiversity

biotic abiotic human activities

biotic factors (living)

* availability of food
* number of predators
* disease
* competition
* grazing

how to use moisture/soil meter

place probe in ground until meter stops moving read correct scaleswitch to correct category

error in moisture/soil meter

probe not left long enough to monitor moisture/pHsample left on probe from previous measurement

How to use a quadrat.

place at random and count squares containing organisms

errors in quadrats

non random sampling incorrect counting

how to use pitfall trap

-add drainage holes + cover
-keep level with surface
-check every 24 hrs

error in pitfall traps

-predation occurs in trap if left too long
-non random sampling

abiotic factors (non living)

pH, temperature, light intensity, moisture

how to use light meters

-hold up towards light source
-read correct scale
-switch to correct category

error in light meter

-standing in way of light and casting shadow on the meter
-light intensity can change throughout the day

how to use thermometer

place in fixed location or place probe in sample

error in thermometer

no left in position long enough to monitor temp.
-temp. may change throughout day

indicator species

organisms that by presence or absence indicate environmental quality (levels of pollution)

Photosynthesis

Conversion of light energy from the sun into chemical energy.

stage 1 of photosynthesis (photolysis)

-raw materials=water+light energy
-products=oxygen,hydrogen,ATP

stage 2 (carbon fixation)

-raw materials=carbon dioxide, hydrogen & ATP from stage 1
-products=glucose

use of sugar in plants

used for respiration, stored as starch, made into cellulose

limiting factors of photosynthesis

light intensity, carbon dioxide concentration, temperature

nitrates are used to

produce amino acids which are synthesised into plant proteins for growth + repair

fertilisers

chemicals added to soil to increase nutrients such as nitrates

main nutrients in fertilisers

* N-nitrogen for leaf growth
* P-phosphorus for root growth
* K-potassium for fruit growth

pesticides

important chemicals used in farming to kill plants and animals which reduce crop yield

leaching

water carriers fertilisers and run off the land into rivers and lochs causing eutrophication

algal bloom

The rapid growth of algae across the surface of water prevents light from reaching plants beneath the surface

algal bloom prevents

plants from photosynthesising and so releasing oxygen into the water and this results in the oxygen concentration of the water decreasing

when plants die after algal bloom

the bacteria which decompose them also use up oxygen in the water even further. This low oxygen concentration can have severe effects by decreasing the biodiversity within the freshwater ecosystem.

bioaccumulation

the build up of a substance (usually a toxin) as it passes through a food chain

biological control

living organisms to control pest species instead of applying chemicals

fertiliser advantage

increase nutrients

fertiliser disadvantage

can leach into water and cause algal bloom

pesticide advantage

kills plants + animals that reduce crop yield

pesticide disadvantage

poisonous for animals

biological control advantage

no chemicals added to the food chain

biological control disadvantage

introduced species can become a pest

mutation

random change of an organism's genetic material, mutations are spontaneous

environmental factors that increase the rate of mutations (mutagenic agents)

* RADIATION

\-uv light

\-gamma rays

\-x-rays

* CHEMICALS

\-alcohol

\-caffeine

advantageous mutation

mutations that can cause changes that leave the organism better off than it was before

neutral mutation

A mutation that has no effect on the organism

disadvantageous mutation

change that gives an organism a decreased chance of survival

evolutionary adaptation

inherited characteristics that enhance organisms' ability to survive and reproduce in specific environments

variation

Any difference between organisms of the same species

natural selection

the best adapted individuals in a population survive to reproduce, passing on the favourable alleles

allele

Different forms of a gene

process of natural selection

Mutation/variation > selection pressures > best adapted > more likely to survive & breed > pass genes on to offspring

selection pressures examples

* starvation
* low disease resistance
* lack of spaces
* lower competition

speciation

the evolution of new species

speciation process

population isolated > groups split by isolation barrier > diff. mutation in each group > natural selection selects for diff. mutations in each group > each population evolves until they become so genetically different they are 2 species

isolation barriers examples

* BEHAVIOURAL

\-migration

* ECOLOGICAL

\-change in abiotic factors

* GEOGRAPHICAL

\-oceans or mountains