B2.6 Old And New Species Flashcards Preview

GCSE AQA Biology (old spec) > B2.6 Old And New Species > Flashcards

Flashcards in B2.6 Old And New Species Deck (20):

What's the difference between vertebrates and invertebrates?

Vertebrates have a spine


What are features of mammals

Don't lay eggs/live young
Females produces milk


What are features of birds?

Lay eggs


What are features of reptiles

Dry scales
Cold blooded


What are features of fish

Wet scales


What are features of amphibians

Moist skin
Gills and lungs


The smallest group an organism can be in is a _________



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
Lack of food
Natural disasters like meteors
Loss of habitat - urbanisation


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
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