Define biological evolution
Organisms change over time.
Evolutionary change within a species or a small group of organisms, especially over a short period.
Ex. genetic makeup of a population from one generation to the next.
Major evolutionary change. The term applies mainly to the evolution of whole taxonomic groups over long periods of time.
Ex. one species evolving into new species over millions of years.
Define gene mutation
A permanent alteration in the DNA sequence that makes up a gene, such that the sequence differs from what is found in most people.
The natural home or environment of an animal, plant, or other organism.
Define selective pressures
Any phenomena which alters the behavior and fitness of living organisms within a given environment. It is the driving force of evolution and natural selection, and it can be divided into two types of pressure: biotic and abiotic. It determines whether a gene mutation is helpful or not.
A group of individuals that interbreed and produce fertile offspring.
Explain the expression “descent with modification”
Refers to the passing on of traits from parent organisms to their offspring.
Describe natural selection
The process whereby organisms better adapted to their environment tend to survive and produce more offspring.
What is a consequence of a species being unable to adapt to its changing environment?
They are more likely unable to survive due to the lack of effective genetic mutations and the lack of their ability to adapt.
Are gene mutations caused by selective pressures in the environment?
Describe the role of geographic isolation in speciation.
Geographic isolation can cause for a species–which are otherwise genetically similar and share a common ancestor–to be unable to interbreed.
List the three leading causes of extinction today.
Habitat loss: species need their habitat in order to survive
Introduced species: new species that live outside of their native area can cause serious damage in a new area
Overexploitation: this is when humans use a species too much and its numbers drop dangerously low
What is the leading cause of extinction today and why?
Habitat loss. Species need their habitat in order to live. If the size of their habitat shrinks, so does the species.
Describe the causes of past mass extinctions.
Mass extinctions are said to be caused by natural causes because they were not caused by humans. They were likely due to wide-scale rapid environmental changes, such as meteor impacts, volcanoes, climate change, etc.
Describe how the current mass extinction is different from past mass extinctions.
Over one half of all plant and animal species will be gone by the end of this century. this current mass extinction is different from past mass extinctions, such as the dinosaurs going extinct and the mammals rising up to take their place, since in the present day we are not seeing new species rise up to take the places of the extinct species.
What does it mean for a species to be endangered?
It means that the species is in danger of extinction throughout all or a significant portion of its range.
What is the goal of conservation biology?
The goal of conservation biology is to prevent a species from going extinct, by protecting the species directly and/or protecting its habitat.
How are mountaintops and islands similar?
Mountaintops represent “islands in the sky” since they are habitat islands that are every bit as isolated as islands in the ocean.