5.2 Natural Selection

3IBA 2022-23 class made Quizlet

What is needed for natural selection to occur?

Variation among members of the same species

What causes variation between individuals in a species?

Mutation, meiosis and sexual reproduction

What are characteristics that make an indvidual suited to its environment and way of life?

Adaptations

How much offspring to species tend to produce?

More than the environment can support

Who tends to survive and produce more offspring?

Individuals that are better adapted

Who tends to die and/or produce fewer offspring?

Less well adapted individuals

What do individuals that reproduce pass on to their offspring?

Characteristics

What does natural selection increase the frequency of?

Characteristics that make individuals better adapted

What does natural selection decrease the frequency of?

Characteristics that don't make individuals better adapted

What does the increase/decrease of frequencies of certain characteristics lead to?

Changes within the species

What is genetic drift?

Change in allele frequency in a gene pool

How does meiosis cause variation?

Production of gametes with unique combinations of alleles increases genetic variation of individuals within the species

When does selection take place?

When there is something to choose from

What does natural selection favor?

Characteristics that support the survival fo the species

What are some environmental factors that affect survival chances?

Predation, competition for food and disease

What processes cause variation during meiosis?

Crossing over and random assortment

What is variation?

Differences between species

What trait was different between Darwin's finches?

Their beak

What is natural selection?

The process by which organisms that are better adapted to their environment survive, reproduce, and pass on their advantageous alleles, causing advantageous characteristics to increase in frequency within a population

Examples of natural selection and variation

Darwin's finches, peppered moth, antibiotic resistance

What is the speciation?

It is the process of individuals in a population separating from the rest of the population and developing unique characteristics

What is the only way that variation can arise in a species asexually?

Mutation

What can be a problem with succession linked to species already living in that habitat?

The successive species could outcompete the native species, becoming an invasive species

How did the polar bear evolve to get white fur?

Over time, the bears with brown or darker fur had a harder time getting food and died

What are adaptations?

Adaptations are features that make an individual better suited to its environment and way of life.

Why is it important for a population to restrict its use of antibiotics?

Bacteria mutate

What is pentadactyl?

The genetic variation of having 5 fingers on one hand, e.g. like humans, whales, dogs and generally a lot of modern living animals.

Which of the following will promote variation in a species?

Meiosis

Fertilization

Why has antibiotic resistance evolved in bacteria?

Bacteria showing resistance to antibiotics survive after antibiotics are used.

Random orientation

Metaphase I gives rise to huge genetic variation

Low fitness

Unfavorable alleles *decrease* over time due to death before reproduction

High fitness

Favorable alleles *increase* in populations as individuals have more offspring

Plasmids

A small ring of DNA

Contains a copy of some genes

Plasmid can be transferred to other bacteria

Antibiotic resistance can spread faster because of this

What is the mechanism of natural selection?

Variations amongst individuals of a population are selected by a changing environment.

Which process has NOT the greatest effect in determining which members of a population are most likely to survive until reproductive age?

Evolution

Meiosis

Hybridization