B2.6 Old And New Species
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What’s the difference between vertebrates and invertebrates?
Vertebrates have a spine
What are features of mammals
Don’t lay eggs/live young Fur Females produces milk
What are features of birds?
Feathers Lay eggs
What are features of reptiles
Dry scales Cold blooded
What are features of fish
Wet scales Gills
What are features of amphibians
Moist skin Gills and lungs
The smallest group an organism can be in is a _________
Species
What does it mean if you’re in the same species as something?
If you’re in the same species you can breed and produce fertile offspring
What are the causes of extinction?
Climate change - global warming/pollution Infertility - radiation Predators - new species Human activity like forest fires Disease Lack of food Natural disasters like meteors Loss of habitat - urbanisation Competition
Define extinction
The disappearance of a species either globally or locally
What’s biodiversity?
The range of different species in an area or worldwide
How much have humans increased the rate of extinction and what’s it causing?
Increased the rate of extinction to 100-1000 times and this causes a decline in global biodiversity
What are the ways to stop extinction?
Renewable energy No deforestation Recycling Responsible tourism Stop using fertilisers No hunting/poaching Stop littering or polluting Reduce the use of fossil fuels
What’s a fossil?
Remains of organisms from many thousands or millions of years ago that are found preserved in rocks, ice and other places
How do fossils form?
The reptile dies and falls to the ground The flesh rots, leaving the skeletons to be covered in sand or soil and clay before its damaged Protected over millions of years, the skeleton becomes mineralised and turns to stone. The rocks shift in the earth with the fossil trapped inside Eventually the fossil emerges as the rocks move and erosion takes place
Why is the fossil record incomplete?
Many of the earliest life forms were soft bodied organisms. This means they have left little fossil trace. Most organisms that died did not become fossilised and many fossils have become destroyed by geological activity. Huge amount of rock have been broken down and as this happens fossil records are lost. There are many fossils still to be found.
When do scientists believe life on Earth began?
3.8 billion years ago
How did dinosaurs become extinct?
It’s not 100% proven by most likely 65 million years ago three could have been a meteorite causing the climate to change dramatically meaning they couldn’t survive. Or there could have been a disease which wiped out the entire population
What’s geographical isolation?
Occurs if an island separates from the mainland or if a new river separates two areas. Natural selection occurs in both areas and the species will adapt differently and eventually become two different species.
What’s speciation?
Two populations of species are separated and natural selection occurs in both areas and the alleles that control the characteristic which help the organism to survive are selected. The organisms with these alleles will survive and breed. Speciation has occurred when two populations can no longer successfully interbreed