Ecology Flashcards
What is genetic variation?
- Many things arise as a result of our genes
What is environmental variation?
things affected by the environment
What is the process of selective breeding?
- The animal breeder selects the sheep from the flock with the most muscle
- Offspring are produced from the sheep selected
- Some of the offspring are more muscular than others
- The most muscular sheep are selected and bred to produce offspring
- An increased number of the population will be muscular
- The breeding programme continues until all flock are muscular
What does the theory of evolution state?
All of today’s species have evolved from simple life forms that first started to develop over 3 billion years ago
Describe natural selection
- there is always wide variation between the organisms within a species due to mutations
- Individuals with a species will be in competition for resources
- The best adapted organisms (i.e. the most successful competitors) are more likely to survive This is known as ‘survival of the fittest’
- The successful organisms that survive are more likely to reproduce and pass on their genes for successful characteristics to their offspring
Name the conditions needed for microbes to carry out decay
- oxygen
- warmth
- moisture
What are fossils?
Remains of an organism that died thousands of years ago
How are fossils formed?
- from parts of organisms that have not decayed because one or more of the conditions needed for decay are absent
- when parts of an organism are replaced by minerals as they decay
- as preserved traces of organisms, such as footprints, burrows and rootlet traces
What is a species?
individuals that resemble one another and can breed together to produce fertile offspring
What is the process of speciation?
- geographical separation
- different environmental conditions
- mutations lead to new alleles
- best adapted in each area survive, breed and pass alleles onto offspring
- speciation (populations can no longer breed to produce fertile offspring)
Why was Lamarck’s theory for evolution not widely accepted?
- changes which occur to an organism during its lifetime are environmental
- only genes can be inherited
What theory did both Charles Darwin and Russel Wallace come up with?
- the theory of evolution
- Darwin proposed this theory in his book ‘On the Origins of the species’
- at the same time, Wallace also proposed the same theory (1859)
What does Lamarck’s theory and Darwin’s and Russel’s theories suggest about evolution? How are they different?
- both suggest that all life have evolved from simple life forms
- they are different, as Darwin and Wallace said that variation in characteristics already present to the offspring, whilst Lamarck said that changes throughout your lifetime can be inherited
- Darwin and Wallace also stated that only those animals who are already adapted are the ones to survive, whilst Lamarck said the animals can change to adapt to survive
Why were so many people against Darwin’s theory on evolution?
- there wasn’t enough evidence
- lack of knowledge of genes and DNA
- goes against religious beliefs
What do we mean by the term extinction?
Extinction is when no living individuals of a species remain
