Chapter 4.1 Flashcards
What is an adaptation?
A structure behavior or physiological process that helps an organism to survive and reproduce in a particular environment
How do adaptations develop?
They are the result of gradual change in the characteristics in members of a population over time
What is a variation?
A visible or invisible difference that helps an individual in a population survive
From where to where are variations passed down?
From survivor to survivor
How are variations affected as they are passed down?
The variation will become so common that it is considered to be a trait or characteristic
Do all variations become adaptations?
No
Are variations always positive?
No, they can be an advantage or disadvantage or they can have no effect on an individual
What is a biological species?
A group of reproductively compatible populations
What is reproduction like in biological species?
The populations can interbreed and produce offspring that are themselves able to reproduce successfully
What creates great genetic variation among populations?
The combination of genes that offspring inherit from their parents
Why would several kittens in a population look different?
Because through sexual reproduction they inherited different genetic combinations
Genetic variation in a population is due to:
The variety of genetic information in all individuals of the population
What are mutations?
Changes in the genetic material of an organism
When does mutation occur?
- They can happen spontaneously when the DNA is copied before the cell divides
- They can also be caused by mutagens
What are Mutagens?
Environmental agents that cause mutations in DNA. ex. UV radiation
What happens to a cell when the DNA mutates?
- A cell may exhibit new characteristics
- A cell may die, malfunction, or multiply
- Some mutations may have no affect on the cell
What happens when a mutated cell multiplies more that it should?
It can result in a cluster of cells forming a tumor
What happens if a mutation occurs (somatic) in the body cells?
The mutation disappears when the organism dies
What happens if a mutations occurs in the DNA of a gamete (reproductive cell)?
The mutation may be passed on to succeeding generations
How do mutations that affect the protein in a cell affect an organism?
They adversely affect the well being of an organism and can be harmful
When can a mutation be positive?
When it enables an organism to survive in its environment better, which means it is more likely to reproduce
When is a mutation that is positive more common?
When an organism’s, environment is changing
What creates a selective advantage?
Mutations becomes favorable due to a new or changing environment
What is selective advantage?
Characteristic that improves an organism’s chance of survival, usually in a changing environment and is the result of mutations
What is an example of a positive mutations?
When some house flies developed a mutation that made them become resistant to DDT. This made only some have an advantage
What can result in populations that become adapted very quickly?
Populations that reproduce quickly, such as bacteria
What is natural selection?
A process where the characteristics of a population of organisms change because individuals with certain inherited traits survive specific local environmental conditions and, through reproduction, pass on their traits to their offspring.
What must there be for natural selection to occur?
There must be variety or diversity within a species
What is a basic way of saying what happens in natural selection?
Populations change and not individuals
What is selective pressure?
Environmental condition or conditions that select for certain characteristics of individuals, and select against others
How is natural selection situational?
Because a trait that seems to have no relevance to survival becomes a trait that later helps individuals in a population to survive and reproduce in a changed environment
What is an easy way of talking about natural selection?
A process by which a population of organisms change because individuals with certain traits can better survive environmental conditions and pass them down to offspring
What can mutations and reproduction cause in a population?
Variations among individuals
What can a mutation provide?
An individuals with an advantage or disadvantages or neutral
