Variation and natural selection Flashcards
define variation
The differences between individuals belonging to the same species
define species
A group of organisms with similar features that can breed together to produce fertile offspring
5 identifiers for variation
colour
size/width/length
area
patterns
shape
histogram for?
variation caused by gene (eg- blood group, hair colour etc)
bar graph for?
variation caused by genes & environment(eg- finger length)
organisms of the same species have the same number of ______________?
chromosomes
scientific name first word –>
genous
scientific name middle word –>
species
scientific name last word (sometimes not there) –>
subspecies
what is a hybrid
a hybrid is a cross of individuals from two different species resulting in a sterile offspring
explain natural selection with an example
1.variation
2.competition
3.adaptation
4.selection pressure
5. survival of the fittest
6. inheritance
7.evolution
- black peppered moth, and white peppered moth–> variation
- compete to survive
- adapt to the trees and camouflage
- selection pressure with industrialisation
5.survival of the black peppered moths who camouflage with the dark tree trunks covered in smog - increase in the number of black peppered moths as the white ones die
- evolution
How does the environment play a role in natural selection?
organisms adapt to what would suit their habitat the best therefore whether a feature is advantageous is determined by the environment around them thus defining what genes are passed on and what aren’t
what are the two types of selection
natural selection and artificial selecation
define competition
members of a population fight for food, they will be killed by predators, die of disease/ lack of enough food
define adaptation
certain variations that allow individuals to be better adapted to their habitat
define selection pressure
caused by change in habitat: drought/flood/rain/temperature change/ volcanic eruption
define survival of the fittest
better adapted individuals will have a better chance of surviving, breeding and having offspring
define inheritance
offspring will inherit the genes and alleles which cause them to have variations required to adapt to have a greater fitness for their habitat
define evolution
Over generations and tens of thousands of years a species may change to have individuals with very different characteristics than the original species
define genetic differences
differences in genes based on dominant &recessive alleles or because DNA replication isn’t exact
what is meant by “some bacteria have become resistant to antibiotics”
one of the bacteria in a population has a gene that is resistant to antibiotics, once the antibiotics kill all the non resistant genes the bacteria with the resistant gene can multiply and form a population of resistant bacteria like itself
Are elephants part of the same of different species?
different:
- Savanna
- Asian
- Forest
are dogs part of the same or different species?
same species; different breeds or subspecies
