- Created by: 12EdwardsonLuk
- Created on: 14-05-14 16:57
Large surface area compared to volume- this means they lose heat energy more efficently, which prevents them from overheating.
Efficient with water-they produce concentrated urine and in small amounts, thisallows them to save water.
Good in hot, dry conditions-Thin layers of fat help them, lose body heat, camels store fat in their humps.Large feet increase surface area making it easier to travel across sand. Certain sandy, yellow colours provide camouflage.
Sleeping times-They would sleepat day, and wake in late afternoon so not to be out in the hottest temperatures.
Burrowing: sand transfers heat energy quickly as it is tighly compacted, therefore to get to the colder sand underneath animals burrow.
The kangaroo rat eats dry seeds, but its body changes the seeds into
food and water.
Small surface area compared to volume- animals in the artic are rounded to reduce surface area; keeping heat loss to a minimum.
Well insulated: Thick layers of fat/blubber to retain body heat, it also acts as an energy store when food is scarce.Thick, greasy, hairy coats, the grease is to shed the water prevnting cooling due to evapouration.
Good in snowy conditions: White fur provides camouflage. Big feet spread weight, which makes transport easier as it prevents sinking.
Many Antarctic animals have either a windproof or waterproof coat. Emperor penguins are a very good example of this. These birds have four layers of scale-like feathers. These layers overlap each other, forming a good protection from the wind, even in blizzard conditions
Minimising water loss: Cacti have spines (which alsodeters predators) instead of leves to minimise water loss and surface area. The small surface area of the cati (100 times smaller than the average plant) rudces water loss. They store water in their thick stem.
Maximising water absorption: some cacti have shallow but extensive roots to absorb water ove large areas when it rains. Others have deep rootsto access underground water.
Colours are sometimes used to deter predators.
Species population size
Organism compete with other spcies (and their own) for resources. Animals compete with territory, food, water and mates e.g. red squirrels and grey squirrels fight for food. Plants also compete with light, water and nutrients from soil.
Disease: Infectious diseases caused by bacteria can severly reduc a population. but it is also a form of natural selection as the strongest survive to pass on their genetics.
Prey to predator ratio: both are dependent on each other to control popultion and keep it sustainable.
Competition for resources
Competition can affect location, size and distribution of wild population e.g. organisms live dependent on their diet like puffins who feed on small seafish so the live by the sea.
Competition for resources means as habitat can only support certain numbers of organisms, the habitat resources and organism are directly proportional.
If there is a lack of resources then organisms tend to spread out and vice versa.
genetic and environmental variations
It depends on the DNA inherited from parents in two halfs; one half from each gamete of parent. Some characteristics are determined by genes only e.g. eye colour, blood group, and inherited disorders and haemophilia is the bodies ability to clot.
Some plants reproduce asexually this means the do not need a mate, but the plants produced are gentic clones therefore they are almost completely identical. The differences between the plants are to do with thhe enironment, e.g. if the are in sunlight the grow healthily, but if it is in darkness it will go yellow and wither.
Most characteristics are due to both as you could have inherited genes for increased muscle growth but if you don't exercise which will affect your physique.
Genes,DNA and chromosones
Nucleus: The nulceus is the is the centre of the cell which contains the geneticm programming that is the base of the structure of you're: apperance and charcteristics, it is called DNA.
Chromosomes: These contain genes where DNA is held and are in the nucleus. There are 23 pairs of chromosones in each cell.
Gene: A gene is a short part of the chromosone.Different versions of the same gene are called alleles.
DNA molecule: A gene is quit a long length of DNA, they coil up to form the arm of the chromosones, whoch are shaped like and 'x'