Old and new species

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Old and new species by Mind Map: Old and new species

1. Extinction

1.1. is the premanent loss of all members of a species

1.2. occurs when conditions change and new species evolve that are better suited and old species cannot cope (cannot compete for food or other resources) so die out

1.2.1. could be climate and environment change - probabaly the biggest influence on survival of species

1.2.2. could be new predators or new more successful competitors

1.2.3. could be new disease caused by microorganisms

1.2.4. some species cannot adapt quick enough

1.2.5. human intervention eg bringing a new species in that preys on exisiting ones

1.3. some species are lost forever but some have close living relatives

1.4. is how evolution takes place and the Earth's species change over time

1.5. mass extinctions have occurred over relatively short periods of time often when catastrophic event happens eg volcanic eruption, giant asteroids collision with Earth's surface. Then many or even most of species are wiped out

1.5.1. eg 65 million years ago dinosaurs became extinct

1.5.2. 2010 evidence of a crater to show a giant asteroid collided with Earth in Mexico

1.5.3. impact casued fires, earthquakes, tsunamis and dust in atmosphere made everywhere dark. so plants died and a global winter then ensued and 50-70% all living species died

1.5.4. although another group of scientists then found evidence in Norway to suggest that dinosaurs bacame extinct much earlier 137million yrs ago due to sea ice melting due to global warming triggering a 9 degree drop in the temp of the sea and mass extinction

2. Fossils

2.1. give some of the best evidence about the history of life on Earth and organisms that lived a long time ago

2.2. are the remains of organisms from many thouands/millions years ago we have found preserved in rock/ice

2.3. revealed world of dinosaurs

2.4. formed in a number of ways

2.4.1. from the hard part of the animal ie bits that do not decay eg bones, claws, teeth or shells

2.4.2. or when the animal/plant doesnt decay after it dies (due either as little or no oxygen present or poisonous gases kill off bacteria that cause decay or temperature is too low = ice fossils although quite rare)

2.4.3. when harder parts of animal/plant replaced by other minerals - takes place over a long time but is MOST COMMON type of fossil

2.4.4. fossils not of the animal/plant itself but traces of what they left behind eg footprints, burrows, rootlet traces, droppings ie

2.5. fossil record incomplete

2.5.1. earliest forms of life were soft bodied so little fossil trace

2.5.2. right condition for formation were rare

2.5.3. much rock destroyed/worn away/buried/melted etc by geological activity so fossils in rocks lost

3. The origins of life on earth

3.1. no record or much valid evidence

3.2. scientists think between 3-4 billion year ago

3.3. many theories and ideas but hard to support them

4. Exploring the fossil record

4.1. we can understand how organisms have evolved over time

4.2. some are complete records eg the horse but some are not and are limited

4.3. some animals have not changed much eg sharks as they were already adapted for their environment and way of life

5. Environment change

5.1. Earths climate has altered a lot over a long period of time

5.2. some organisms do well in icy conditions but cannot survice in a tropical climate. So man y species become extinct by not coping in hot or cold

5.3. change in environment may mean a lack of food causes extinction

5.4. mammals survived temp change as they can control their own body temp whereas dinosaurs could not