7 Evolution Flashcards
In three points explain how natural selection leads to evolution?
Mutation
Individuals with characteristics most suited to environment survive
Genes passed to next generation
What does oestrogen inhibit?
FSH
describe what happens at a synapse during reflex?
Chemical release
Diffuses across the gap
Transmits impulse across synapse
Between neutrons
What scientist suggested an alternate explanation for evolution?
Lamarck
What is classification?
The organisation of living things into groups according to their similarities
Why do most scientists only accept darwins theory?
More evidence
Genes discovered
What inhibits FSH production?
Oestrogen
How does natural selection work?4
- by selecting the organisms best adapted to a particular habitat
- different organisms in a species show a wide range of variation because of their genes
- those with the characteristics most suited to their environment are most likely to survive and breed w success
- these genes that have produced successful characteristics are then passed on to the next generation
What is the evidence that evolution has taken place?
That evolution takes place through natural selection
What does the theory of evolution state?
Present day organisms have evolved from simpler organisms over long periods of time (billions of years)
Why was Darwins theory of evolution only gradually accepted?
- there was conflict between the belief that God made all the animals and plants on earth
- Insufficient evidence
- no way of explaining variety and inheritance ( because genetics weren’t understood until another 50 years)
How does classification help us understand evolution?
It helps us understand ecological and evolutionary relationships
Explain how natural selection occurs?
Mutation / variation in population
More advantageous get more food /territory/ light etc
These survivors breed more
Pass on genes
Why were people against darwins ideas?
Religious objection
Insufficient evidence
What wasent known in the 1800s
Genes and DNA weren’t discovered
What is mutation?
A change in genetic material (DNA) which results in a new form of a gene
Lamarcks theory? Eg with elephant trunk
Ancestor stretches nose to reach food
Passed on this stretched nose to offspring
Why were people against darwins ideas?
Religious objection
Insufficient evidence
What is a mutation?
A change to the genetic material / DNA
In an organism
Who has Jean-Babyiste Lamarck?2
- a French biologist
- who proved the inheritance of acquired characteristics
In three points explain how natural selection leads to evolution?
Mutation
Individuals with characteristics most suited to environment survive
Genes passed to next generation
What is a hormone?
A chemical messenger
Produced by a gland
That acts on a target organ
Controls body functions
What stimulates the maturing of the egg?
FSH
What did people think before Darwin about evolution?
God made all living things
What does FSH stimulate?
Oestrogen production
Egg maturing
What is the theory of evolution?3
- the theory of evolution states that all the species which are alive today
- many more which are now extinct
- evolved from simple life forms that first developed more than 3 billion years ago
How can animals be adapted against predators?
Camouflage - less likely to see prey
Warning colours - likely to confuse prey with a poisonous organism
Prickles - sharp and hurts predator
Long limbs/ streamlining - increase speed to outrun predator
Position of eyes - prey can escape sooner
Poison - spit out prey not attack again
What is a categoric variable?
One best described by a label
Eg colour of eyes
What is a continuous variable?
Quantities found by measuring a variable eg temperature
How is a measurement repeatable?
If same person can repeat it using same method and equipment and get same results
How is a measurement reproducible?
If someone else can do it and get the same results
Increasing accuracy?
Repeat measurements and find a mean
Repeating with different instruments
High quality instruments
Be careful
Increasing precision?
Repeat tests the same small scale divisions
What does darwins theory state?
That all living things have evolved from simple life forms that developed more than 3 billion years ago
Why was natural selection only gradually accepted?
Challenged the idea that God made all animals + plants that live on earth
Insufficient evidence
Inheritance and variation was not known until 50 years
Why couldn’t scientists decide between lamarcks theory and darwins theory?
Insufficient evidence for both
Mechanism of inheritance was not known
Genes not discovered
