Biology

Genetic Variation -

Inherited from parents - Passed on in sex cells ( Gametes ) - Combining of genes from 2 parents causes genetic variation ( No clones )

1 of 28

Environmental variation -

Condtions that organims live and grow in causes differences between members of the species.

2 of 28

Survival of the fittest -

Organisms in a species have a variety of different characteristics, the organisms which have the best characteristics suited to its surroundings will have a much higher chance of survival an breeding - passing on their characteristic.

3 of 28

Specification -

Over time, the phenotype of organisms can change so much because of natural selcetion it can form a new species.

4 of 28

Causes of Extinction -

Enviroment changes too quickly / New predator kills them all / New disease / Cant compete with another ( new ) species for food / A catastrophic event.

5 of 28

The water cycle -

1. Evaporation 2. Condensation 3. Precipitation ( Rain / Snow ) 4. Percolation (Water goes through gaps in the soil / rocks. ) 5. Transpiration.

6 of 28

Quick decay =

Temperature + Moisture + Oxyegn

7 of 28

Slow(er) Decay =

Keep out of sunlight + Air tight places +Keep below 0 degrees + Dry it

8 of 28

Bioaccumulation

Toxins build up in a food chain

9 of 28

Eutrophication

Excessive richness of nutrients within a body of water

10 of 28

Nervous Control

Fast action - Act for a short time - Precise area ( receptor ) - Stimulated - Impulses in neurones

11 of 28

Hormonal control

Slow action - Act for a long time - General area - No stimuli - Chemicals - Adrenaline

12 of 28

Reflex action =

Stimulus ~ Receptor ~ Neurone ~ Spinal cord ( CNS ) ~ Motor Neurone ~ Effector ~ Response

13 of 28

Synapses

Gaps between neurones

14 of 28

Rod cells

Rod shaped - Greater numbers - Poor visual acuity - Low light intensity - Greater distribution

15 of 28

Cone cells

Cone shaped - Good visual acuity - Not sensitive to low intensity

16 of 28

Light travels through :

Cornea -> pupil -> Lens -> retina

17 of 28

Endocrine System

Controls hormones , Chemicals , long lasting effect , cover a general area

18 of 28

Blood Glucose levels rise =

Pancreas releases insulin > In response to insulin target cells take up glucose and the liver converts glucose to glycogen > Blood glucose levels fall > Pancreas produces glucagon >The liver breaks down glycogen into glucose into the blood.

19 of 28

Food tests

Benedict's - glucose - blue > red Biuret - protein - blue > lilac Sudan 3 - fat - layer of red Iodine - Starch - orange > black

20 of 28

ADH

Secreted by pituitary gland ~ Steps in to rebalance the water concentration ( Negative feedback ) ~ needed on a hot day more so

21 of 28

Tropism

Phototropism = Response to light Geotropism = Response to gravity Hydrotropism = Response to water

22 of 28

Auxins

Group of growth control hormones , IAA causes plants to elongate

23 of 28

Mitosis

Cell division - Occurs in every cell in the body - everywhere except testes / ovaries - asexual / clone - bacteria

24 of 28

Meiosis

Occurs only in the sex cells - Sperm ( Animal ) - eggs / ovum cells - Pollen ( male - plants )

25 of 28

DNA

Double helix - T-A / C - G - bases - Amino acids

26 of 28

Allele

Each half of a chromosome is an alle

27 of 28

Homo / Hetro zygous

Homozygous = both the same type of alle heterozygous = One of each type of alle

28 of 28

Get Revising

Biology

Other cards in this set

Card 2

Front

Back

Card 3

Front

Back

Card 4

Front

Back

Card 5

Front

Back

Comments

Similar Biology resources:

Other cards in this set

Card 2

Front

Back

Card 3

Front

Back

Card 4

Front

Back

Card 5

Front

Back

Comments

Related discussions on The Student Room

Similar Biology resources: