B2 Understanding Our Environment Flashcards
How can organisms be organised into groups?
According to shared characteristics
Describe insects
Bees or butterflies
6 legs
Body divided into 3 sections
Usually 2 pairs of wings
Describe arachnids
Spiders or scorpions
Eight legs
Body divided into 2 sections
Describe crustaceans
Crabs or woodlice
Ten legs
Body covered in hard outer covering
Describe myriads
Millipedes and centipedes
Each body segment has legs
Long, segmented body
What are the different classes of anthropod
Insects
Arachnids
Myriapods
Crustaceans
Organisms of the same species
- may show great variation
- have more features in common than they do with organisms of a different species
Why is it difficult to place organisms in to distinct groups
The variety of life is a continuous spectrum which makes it difficult for organisms to be placed in to distinct groups
Describe the order of classification
Kingdom Phylum Class Order Family Genus Species
Describe systems to include artificial and natural systems
Artificial is based on visible features
Natural is based on evolutionary links (common ancestor)
Explain how the use of DNA sequencing information had lead to the change in understanding classification of organisms
Organisms may be more closely related when compared physically. A natural system needs to adjust to form more accurate links between organisms
Define the term species
A group of organisms that are capable of interbreeding to produce fertile offspring
Explain the importance of the binomial system
The international basis of naming organisms
Explain some problems of classifying organisms into species
Hybrids
Organism that can reproduce asexually only
Evolution as a continuous process
Closely related species can: (2)
Have a common ancestor
May have different features if they live in different types of habitats
Explain how similarities and differences between species can be explained into terms of both evolutionary and ecological relationships
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Explain the term trophic level
Each link in the food chain is a separate feeding level
Explain the difficulties in constructing pyramids
Organisms may belong to more than one trophic level
The problems with measuring a dry biomass
Explain how some energy is lost at each trophic level in a food chain
Heat from respiration
Movement
Excretion
Egestion
When animals and plants die and decay the elements in their bodies are recycled
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Describe the importance of the decay process
It makes elements available for organisms again
How is carbon taken up by plants
As Carbon Dioxide
How is nitrogen taken by plants
As nitrates
What do plants compete for?
Space Light Water Minerals Carbon dioxide
What do animals compete for?
Food Space or territory Mates Water Shelter
The size of a predator population will affect the numbers of prey and vice versa
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Define interspecifc
This is between organisms of different species. Red squirrels and grey squirrels compete for the same food
Define intraspefic
This is between organisms of the same species, such as two troops of baboons on the African plains. This type of competition is more significant because the needs of the two groups are identical
Explain what is meant by the term ecological niche
The unique way of surviving in its environment
Explain why the cycles of population for predator and prey are out of phase with each other
They are out of phase because when the population of predators is high, it will mean they will kill more preys, decreasing the population
Describe the different types of interdependence between organisms
- Parasitism: where the parasite benefits to the living host’s detriment (fleas and tapeworms)
- Mutualism: where both species benefit including cleaner species and pollination by insects
Explain how some animals are adapted to be successful predators
Binocular vision to help judge distance and size
Hunting strategy
Breeding strategy
Explain how preys are adapted to avoid being caught
Monocular vision for a wide field of vision
Living in groups or herds to reduce chances of being caught
Cryptic and warning colouration
Mimicry
Breeding strategy (synchronous breeding - reproduce when the population of the predators is low)
Plants and animals are adapted to their habitats are better able to compete for limited resources
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Explain how adaptations to cold environments help organisms to survive
Thick white fur Small nostrils Sharp teeth Blubber below the skin Counter-current exchange system (cool blood from the foot returning to the body, warm blood from the body goes to the foot, heat from the descending blood warms the returning blood)
Explain how adaptations to hot environments help organisms to survive
Dry dung and concentrated urine Hump of fat Nostrils which close Bushy eyebrows Body tolerance to temperature change Long legs Large feet Thin fur Large ears Large body size Wrinkled skin (increases SA to Volume ratio) Large feet
Explain how adaptations to dry environments help organisms to survive
Reduced surface area to reduce water loss
Thick wax on the surface of the leaf to reduce water loss
Pine needles have fewer pores which can lose water
Leaves can fall during the autumn as there is not much light, hence not much of use
Rounded shape reduces SA to Volume ratio
Thick wax cuticle reduces water loss
Shallow roots cover large areas
Green stem for photosynthesis
Explain what is meant by organisms being specialist
Being well suited to a certain type of habitat
Explain what is meant by organisms being generalist
Can survive in a range of habitats but can easily be out competed
Explain Darwin’s theory of evolution by natural selection
- presence of natural variation
- competition for limited resources
- survival of the fittest
- inheritance of successful adaptations
Explain how over long periods of time, the changes brought about by natural selection may result in the formation of a new species
Evolution is the gradual change in of an organism over time. If an organism’s surrounding change, the organisms with the natural variation will survive, whereas the ones which lack such a variation will die. The remaining organisms will mate and increase the population once again
Why speciation requires geographical or reproductive isolation of populations
- The populations get separated by some kind of barrier. This may be a geographic barrier (river, mountain range,etc) or behavioural (reproductive seasons not coinciding)
- Over time each separated group of population evolves differently on each side of the barrier. The longer the separation, the more distinct they will become from each other
- The two sub-populations have changed so much that they can’t interbreed. They have formed separate, yet closely related species
Why is the theory of natural evolution is widely accepted
- because it explains a wide range of observations
- because it has been discussed and tested by a wide range of scientists
Explain Lamarck’s idea of evolution and how it differs to Darwin’s theory
Lamarck states that the giraffes would stretch their neck in order to reach the food higher up in the tree and the ones who were incapable would die. The successful giraffes with the longer necks would survive and pass this on to their offspring. However this isn’t possible as the only changes that can be passed down to the offspring is the changes in genes, not changes acquired in a lifetime.
Darwin states that the offspring receives the variation in genes which causes it to be successful
Explain why Lamarck’s theory of evolution was discredited
His explanation didn’t have a genetic basis
Give 3 examples of variation
- The peppered moth
- Bacteria
- Warfarin resistance in rats
Which finite fuels are used by the human population?
Minerals
Fossil fuels
Explain how as the human population increases, resource use increase and therefore more pollution is created (4)
Household waste
Sewage
Carbon dioxide from burning fossil fuels
Sulfur dioxide from burning fuels
How is the human population increasing?
Exponentially
What is the population growth a result of?
Birth rate exceeding the death rate
Explain the cause and effects of :
- Global warming
- Acid rain
- Ozone depletion
Global warming is caused by the excess release of greenhouse gases, this increases the temperature of the planet as the infrared heat is absorbed by such Greenhouse gases
Ozone depletion is caused by the use of CFCs which allows more UV radiation through contributing to several medical problems
Acid rain is caused by Carbon dioxide, Sulfur dioxide and nitrogen oxides. The pollutant dissolves in the rain to form acidic rain and causes:
- Damages plant leaves
- acidifies lakes
- changes minerals available in water supplies
- causes bronchitis
Explain the term carbon footprint
The amount of greenhouse gases released in a certain period of time
Explain how water and air pollution can be measured
Water pollution - Waterlouse, sludgeworm, rat-tailed maggot, mayflay larva
Air pollution - lichens
Describe how pollution can be measured
- by direct measurement of pollutant levels
- by measuring the occurrence of indicator species
Explain why organisms have become endangered or extinct (5)
Climate change Habitat destruction Hunting Pollution Competition
Describe how endangered species can be conserved
Protecting habitats Legal protection Educational programmes Captive breeding programmes Creating artificial ecosystems Seed banks
Discuss the reasons why certain whale species are close to extinction
Their numbers are falling below a critical level
There isn’t enough genetic variation in the population
Explain how fish stocks and woodland can be sustained and developed
Quota of fishing
Replanting of woodland
Education
How can you evaluate a conservation programme (4)
Genetic variation of species
Viability of populations
Available habitats
Interaction between species
Explain reasons for conservation programmes
Protecting human food supply
Ensuring minimal damage to food chains
Cultural aspects
Future identification of plants for medical purposes
Describe issues of keeping whales in captivity
Isolation
Lack of freedom
Captive breeding
Breach of animal rights
Benefits of keeping whales in captivity
Entertainment
Tourism
Research
Commercial uses of whales when dead or alive
When alive: - tourism When dead: - food - oil - cosmetics
What aspects of whale biology remain not fully understood
Communication
Migration patterns
Survival at extreme depths
Describe issues concerning whale protection
Getting international agreements
Difficulty in policing and enforcing such agreements as whales live in a range of locations
How humans contribute to extinction of species
Human building activities destroy habitats
Humans often over hunt animals for food or pleasure
Human activities often pollute the environment
Human over-compete with animals for resources such as food
Climate change can cause species to die out- humans contribute to this change
How does human agriculture contribute to changes in the environment
Use of fertilisers and pesticides
Loss of habitats
Deforestation
Animal waste
How do towns and industries influence the environment
Loss of habitat Quarrying and extraction of raw materials Dumping of waste Production of toxic chemicals Sewage
