IB Biology Topic D4.1 Natural Selection Revision…

Natural Selection Makes Advantageous Traits More Common Over Generations

Definition

Natural selection

Natural selection is the process where individuals with traits better suited to their environment have higher reproductive success, passing these traits to the next generation.

Definition

Paradigm shift

A fundamental change in understanding.

Natural selection is the process by which heritable traits that improve survival and reproduction become more common in a population over generations.
It is the main mechanism that drives evolutionary change.
Charles Darwin and Alfred Russel Wallace proposed it independently, and their joint papers in 1858 replaced the older idea that species were fixed and unchanging.

Four Conditions Must Hold at Once for Selection to Act

Variation
1. Individuals in the population differ in their phenotypes.
Heritability

Natural Selection Makes Advantageous Traits More Common Over Generations

Definition

Natural selection

Natural selection is the process where individuals with traits better suited to their environment have higher reproductive success, passing these traits to the next generation.

Definition

Paradigm shift

A fundamental change in understanding.

Natural selection is the process by which heritable traits that improve survival and reproduction become more common in a population over generations.
It is the main mechanism that drives evolutionary change.
Charles Darwin and Alfred Russel Wallace proposed it independently, and their joint papers in 1858 replaced the older idea that species were fixed and unchanging.

Four Conditions Must Hold at Once for Selection to Act

Variation
1. Individuals in the population differ in their phenotypes.
Heritability

D4.1A Natural selection: variation, competition and selection pressures

D4.1A Natural selection: variation, competition and selection pressures

Subtopics and learning objectives

D4.1.1 Natural selection as the mechanism driving evolutionary change

Natural Selection Makes Advantageous Traits More Common Over Generations

Four Conditions Must Hold at Once for Selection to Act

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Natural Selection Makes Advantageous Traits More Common Over Generations

Four Conditions Must Hold at Once for Selection to Act

Unlock the rest of this chapter with a free account

A - Unity and Diversity

B - Form and Function

C - Interaction and Interdependence

D - Continuity and Change

D4.1A Natural selection: variation, competition and selection pressures

A - Unity and Diversity

B - Form and Function

C - Interaction and Interdependence

D - Continuity and Change

D4.1A Natural selection: variation, competition and selection pressures

Subtopics and learning objectives

D4.1.1 Natural selection as the mechanism driving evolutionary change

D4.1.2 Roles of mutation and sexual reproduction

D4.1.3 Overproduction of offspring and competition for resources

D4.1.4 Abiotic factors as selection pressures

D4.1.1 Natural selection as the mechanism driving evolutionary change

Natural Selection Makes Advantageous Traits More Common Over Generations

Four Conditions Must Hold at Once for Selection to Act

Unlock the rest of this chapter with a free account

Natural Selection Makes Advantageous Traits More Common Over Generations

Four Conditions Must Hold at Once for Selection to Act

Unlock the rest of this chapter with a free account