ALL YEAR 8 SCIENCE

ALL YEAR 8 SCIENCE <3

inherited variation

due to genetic information inherited from parents- genes

environmental variation

due to the environment

continuous variation

where differences between living things are grouped into categories and given a name/ label

discontinuous variation

where difference between living things are given a numerical/ number valueg

gene

a section of dna which determines a characteristic

how many chromosomes are in a cell

46

how many chromosomes are in a egg/ sperm cell

23

what is a different version of a gene

allele

how old is the earth

4.5 billion

survival of the fittest

the idea that only the strong can survive and breed

population

group of organisms of the same kind living in the same place

natural selection

theory that animals and plants living today descended from species that existed in the past

extinct

when no more individuals of a species remain

biodiversity

the variety of living things. it is measured as the differences between individuals of the same species or the number of different species in an ecosystem

competition

when two or more living things struggle against each other to get the same resource

evolution

process by which species change over time in response to environmental changes and competition for rescources

what are the 4 causes of extinction

destruction of habitat, predators, disease, mutations

what are changes in genes called

mutations

how can you increase the strength of an electromagnet

have a large iron core, add more turns/coils, increase the current

electromagnet

a type of magnet that is powered by electricity

what are some everyday electromagnets

bell, loudspeaker, car park barrier

alternating currents

a current that goes back and forth

what’s the abbreviation for alternating current

a.c

how many layers is the earth’s atmosphere split into

5

what are the 5 layers of the earth’s atmosphere called

troposphere, stratosphere, mesosphere, thermosphere, exosphere

how thick is the troposphere

10km

how thick is the stratosphere

40km

how thick is the mesosphere

50km

how thick is the thermosphere

300km

how thick is the exosphere

10,000km

how much percent of the atmosphere is made up of nitrogen

78%

how much percent of the atmosphere is made up of oxygen

21%

how much percent of the atmosphere is made up of other gases

1%

what is the word equation for rusting

iron + water + oxygen = hydrated iron oxide

fossil fuel

a fuel that is made over millions of years under pressure and is mined from the earth. they will run out

how was coal formed

dead plants under pressure

how was oil and gas formed

dead animals under pressure

what are the main 3 greenhouse gases

carbon dioxide, methane, water vapour

global warming

the long term heating of the earth by co2

climate change

the long term shift of the earth’s climate

300, 000 km per second

how fast does light travel

8 mins

how long does it take for light from the sun to reach earth

transverse wave

what type of wave is this

longitudinal wave

what type of wave is this

red, blue, green

what are the primary colours in science

concave lens

what is this?

concave lens

what is this?

goes through the object

transmitted

absorbed

light goes into the object

causation of shadows

when light is blocked by an object and causes a dark area, because light cannot go through the object in front

by light reflecting off objects into our eyes

how do we see

amplitude

the distance the particles move each side, measured from their rest position

to either side of their rest position

how do sound waves vibrate the particles

echolation

the use of echos to measure distances

between 20HZ and 20 000 HZ

what frequencys can human ears detect

Hertz (Hz)

what do you measure frequency in

frequency

the speed of the vibration of a sound wave

there are no particles to vibrate

why can’t sound travel through a vaccum

mechanical waves

what type of waves are sound waves

electromagnetic waves

what type of waves are light waves

incident ray

a ray of light that hits a surface

reflect, refract or absorb

what are the 3 things light rays do when they hit a surface

reflection

when light bounces off an object into your eyes

transparent

allows light to pass through

translucent

allows some light through

opaque

allows no light to pass through

what are the five groups of animals

fish, amphibian, reptiles, birds and mammals.

joint

when 2 or more bones meet allowing movement when 2 or more bones meet allowing movement

what do muscles do

they allow the bones to move by contracting and relaxing

what do bones do

they provide support to the body

tendon

attaches muscle to bone. Doesn’t stretch

how many bones does an adult have

206

what are the 2 types of tissue that a bone is made of

living and non living

define non living tissue

hard material that supports the weight of the body and is pulled by the muscles to cause movement.

define living tissue

where the body makes blood cells, it is called bone marrow. red blood cells carry oxygen around the body and white blood cells fight diseases

what would happen if 2 bones moved against each other

they would wear away

what do ligaments do

join 2 bones and can stretch.

name the 3 types of muscle

cardiac muscle, skeletal muscle and smooth muscle

cardiac muscle

the heart

smooth muscle

intestines and oesophagus have walls that are made from layers of muscle. these muscles allow the food to be churned and pushed through the digestive system

skeletal muscle

pull upon bones and cause movements of the organism in vertebrates

word equation for respiration

sugar+oxygen>carbon dioxide+water

rib muscle

allow the rib to move. increases the volume of thoracic activity

rib

protects lungs and provides sctructure

trachea

allows air to travel from mouth to lungs

diaphragm

contracts and flattens when we breath in

journey of air from outsde to inside our body

atmosphere> nasal passages> larnyx> trachea> bronchus> bronchioles> alveoli

alveoli

singular form of alveolus. each of your lungs contains millions of alvioli and they help diffuse carbon dioxide into the blood.

gaseus exchange

he movement of oxygen from the alveoli the the capillary and the movement of carbon dioxide from the calillerary into the alveoli

where does respiration happen

mitochondria

what does respiration do

provides energy

what respires

all living cells

hinge joint

A joint that moves simply, like a door opening and closing. Knees, elbows

ball and socket joint

Allows more movement in more directions. Shoulder.

flower

the reproductive organ of plants, often attractive or sweet smelling to insects

fruit

the ripe part of a seed-bearing plant, often fleshy and edible to animals

seed

the part that the plant will lose and can then develop into a new plant

leaf

where photosynthesis occurs. contains chlorophyll and absorbs light energy

stem

supports the plant, holding it upright and growing taller