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
- Geneus - type of closely related species animals that can interbreed
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
- 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
- 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.
- 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.
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
Compete to survive
- 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
Cycle of population
- 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
Parasitic and mutualistic
- So where an orgsanism lives and its abundance(population size) is infulenced by the distribution and abundace of these species
- Live of a host
- Take what they need to survie without giving anthing back
- This harms the host
- Win lose situation
- 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
- Organsisms that are highly adapted to survive in specific conditions .
- 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
- 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
- Organisms in very cold environments hava special antifreeze proteins
- Proteins interfere with formation and growth of ice crystals stopping cell damage.
Adaptations to cold weather
- 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
Adaptations for hot weather
- 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.
- 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.
- 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