Biology iGCSE Notes

Section 1

a)
Movement
Respiration
Sensitivity

Homeostasis

Growth
Reproduction
Excretion
Nutrition

Section 2

a) organelles - cells - tissues - organs - systems - (organism)

Section 3

a) Reproduction
Flowering Plants

• Asexual reproduction by runners (natural) and cuttings (artificial)
• Germination needs O2, H2O and the correct temperature

Section 4

a) The organism in the environment

Population - All the organisms of the same species living in an ecosystem at a particular time

Community - All the populations of different organisms interaction with their habitat

Habitat - A place where specific organisms live

Ecosystem - A community of organisms interacting with each other and their habitat/environment

• Quadrats. Populations size - Count no. of species in square. Repeat and avg. Multiply avg. by area of field.

• Quadrats. Distribution of organisms - Place quadrants in different locations. Compare the density/no. of species

Section 5

a) Food production

• Pesticides : +ve = Very effective. Kill all the pests. -ve = Expensive, pests can become resistant, cause env. damage as some remain in soil and food chain, kills other organisms too
• Biological control : +ve = Cheap. Self regulating as predator won't kill itself + reproduces. -ve = does not kill ALL the pests. Predator may enter the wild and affect biodiversity

• CO2 production by yeast experiment - Add sucrose solution + oil layer (blocks air) andplace in different temp water baths. Collect Co2 over water in measuring cylinder to measure rate. Use limewater to test
• Lactobacillus bulgaricus
• Fermenter: aseptic conditions = Sterile. Filter air and sterilise the fermenter

• Intraspecific predation - Fish of the same species eat each other. Separate different age, gender & feed often
• Interspecific predation - different species eat the fish