4.7 Explain why only about 10% of energy is transferred from one trophic level to the next.

• Some energy is used at the current trophic level in life processes
• Some food the organism takes up is undigested and passed as faeces
• Organism might not eat everything (i.e. a rabbit won't eat a cabbage's roots, so won't gain 100% of its energy even if no energy was used by the cabbage)

4.6 Understand the transfer of substances and of energy along a food chain

When one organism eats another, the substances and energy from it get transferred to its consumer. I.e. if you eat a kilo of spinach, the energy and nutrients from that are transferred to you (don't try that please)

2.90 understand the sources, roles and effects of the following hormones: ADH, adrenaline, insulin, testosterone, progesterone and oestrogen

Basically everything you need to know is above, sorry if my handwriting is unreadable and messy ↑

4.5 Understand the concepts of food chains, food webs, pyramids of number, pyramids of biomass and pyramids of energy transfer

Food chain
Shows energy transfer between producers all the way to tertiary consumers. Only 1 line
eg: grass > zebra > lion

Food web
Shows links between various food chains within the same habitat or environment
eg:

Pyramid of numbers
Shows number of organisms in each trophic level and isn't always a nice pyramid shape
eg:

Pyramid of biomass
Shows mass of organism in each trophic level, and is almost always a pyramid shape
eg:

Energy transfer pyramid / chain
Shows energy transfer between organisms, typically in a food chain
eg

4.4 Explain the names given to different trophic levels to include producers, primary, secondary and tertiary consumers and decomposers

Producers
Produce their own 'food' (glucose) from the sun's light energy

Primary consumer
Eats (consumes) producer and gains its energy; often a herbivore

Secondary consumer
Eats (consumes) primary consumer and gains its energy; often an omnivore

Tertiary consumer
Eats secondary consumer and gains its energy; top of the food chain; often a carnivore

When these die, they're broken down by fungi and bacteria. Nitrogen and carbon compounds are returned to the earth (see cycles)