B2

Natural classification system- Based on evoluntionary relationships and genetic similarities

Artificial classification-based on appearance rather than genes used to identify organsisms

• Living things are divided into kingdoms
• Kingdoms are subdivided

• Kingdom 
• Phylum
• Class
• Order
• Family
• Geneus - type of closely related species animals that can interbreed
• Species

Newly discovered spieces

• Might not fit into any categories 
• DNA sequencing allows us to see genetic differences between different groups. 
• When this is collected we might see that they rae not as close as we thought but could be relatives

Evolutionary trees

• You can draw evolutionary trees to show how closely related speices are.
• They show common ancestors 
• Studying charateristics for a large group of organsims inclused anaylsing DNA
• Closely related species have recent common ancestors they tend to live in similar habitats 

Species- Is a group of organsisms that can interbreed to procude fertile offspring

Asexual reproduction

• Bacteria 
• The organsim reproduces by making a cop of itself. 
• There is no interbreeding with another orangism so they dont ift into the definition of a species. 

Hybrids

• If you interbreed a male from one species and a female from another you get a hybrid.
• They aren't a new species so its difficult to classify them 

Evolution is a continuous process

• Organsims evolve over time
• The way they've been classified might change so much it froms a new species

• Each species is given a two part name
• The first part is about the genus 
• The second part is about the Species
• The system is used all around the work so that scientist have the same name for everything although they speak different languages

Trophic level- feeding level 

• Each pyramid of biomass shows the mass of living material usually in KG
• The bar that is at the bttom is the first thing in the food chain 
• To contrust a pryamid the dry biomass iof the organsisms is used. 

Pyramids of numbers

• Each bar is the number of organisms not their mass.

eg .

A bar of pear trees can be small beacuse one pear tree can feed lots of animals but in a biomass pyramid one pear tree is alot heavier than the animals it feeds.

• Energy from the sun is the main source of energy
• Plants use energy from the sun to make food from photosynthesis
• Energy lost at each stage is used for respiration 
• Most of the energy is lost to surroundings as heat 
• Material adn energy is lost from the food chain as waste products (egestion and excretion)
• Waste products and uneaten parts become a starting point for other food chains.

Most biomass is lost so doesnt become biomass in the next level up.you hardly ever get more than five trophic levels because of this , energy is lost at each stage so theres not enoughtto suport the organisms after four, five stages.

Energy flow Effciency =              Energy avaliable to the next trophic level                                                                                      Energy that was avaliable to the previous trophic level

• Similar organsisms are in closest competition as they copete for similar ecological niches
  • Ecological niche is how an organism fits into its ecosystem it depends on where the individuals live and what they feed on.

Types of competition 

• Interspecific competetion - Competition between different species
• Intraspecific competition- Comepteition bewteen the smae species

• Population is limited depending on amount of food avaliable
• If the population of prey increases the population of predators increases
• When the prey decreases the preadators decrease
• When the preadators decrease the prey increase beaucse they are not eaten as much 
• The cycle carries on

• So where an orgsanism lives and its abundance(population size) is infulenced by the distribution and abundace of these species

Parasites

• Live of a host
• Take what they need to survie without giving anthing back 
• This harms the host
• Win lose situation

Mutalism 

• A relationship where both organsisms benifit 
• Win win situation

• Features that make an organsim better suited to their environment
• Organsims that are adapted can compete better for resources
• More likely to survive, reproduce and pass on adaptations to children 

Specialists

• Organsisms that are highly adapted to survive in specific conditions . 

Generalists

• Organsisms that are adapted to survive in a range of different habitats.

• Some organsims can tolerate exterme conditions
• EXTREMOPHILES- Organsims that can live in seriously extreme conditions

HOT 

• Extremophiles bacteria can live in very hot conditions and can work at higher temps than enzymes from other organisms
• Are able to function normally at temps that would denature enzymes from other organsisms

Cold 

• Organisms in very cold environments hava special antifreeze proteins
• Proteins interfere with formation and growth of ice crystals stopping cell damage.

• Anatomical adaptations are features of an orgasims anatomy (body structure)
  • Having a thick coat , layer of blubber, to insulate the body (trap heat)
  • Large size and compact body shape. to give small surface area to volume ratio.(this reduces heat loss as less body heat can be lost through SF of skin )
• Animals like penguins have to stand on ice all day. 
  • Blood vessels going to and from the feet carry blood that flows in opposite directions.
  • The vessels pass close to transfer heat between them 
  • warm blood in arteries to the feet heat the cold blood returning to the heart.
  • This means the feet stay cold but the cold blood doesnt cool down the rest of the body 
• Species also migrate to warmer climates in the winter months
• Hibernate to save enery
• Huddle together to keep warm

• Animals in very hot climates stay in the shade or underground to minimise the amount of heat their bodies gain from surroundings
• Being active at night reduces heat gain as its much cooler at night
• Increase heat loss by bathing in water,as the water evaporates the heat transfers from the skin to the surroundings
• Animals adapted for hot weather are normally small
  • Gives them a large surface area to volume ratio to help them lose heat
  • large thin ears allow more blood to flow near the surface of the skin so more heat from the blood can be radiated to surroudings
  • Store fat in one paret of the body, stop the body from being well insulated and allows heat to be lost easily.

Plants 

• Rounded shape-Small surface area to volume ratio to minimise water loss from the surface
• Thick waxy layer (cuticle)
• Spines instead of leaves to reduce water loss
• Store water in stems to allow survival in drought
• Shallow but etensice roots to ensure water is absorbed quickly over a large area.

Animals

• Speacialised kidneys- Produce very concentrated urine, with a very low water content
• No sweat glands- Less water loss from sweating
• Lots of time in an underground burrow where air contains more moisture than on the surface