Niches & Symbiosis
The role an organism plays in its environment
What is a niche?
the two types of variations seen in nature
Interspecific and intraspecific variations
the main difference between sexual and asexual reproduction
Sexual involves two parents; asexual only one
What is DNA made of?
Sugar-phosphate backbone and nitrogen bases (A, T, G, C)
developed the theory of natural selection
Charles Darwin
The species no longer exists anywhere on Earth
extinct
What do generalists and specialists refer to?
Generalists live in many environments; specialists in few
What are variations that help an organism survive called?
Adaptations
A one-celled organism copies DNA and splits into two identical cells
binary fission
What process forms gametes?
Meiosis
This phrase summarizes natural selection
Survival of the fittest
the name of the current mass extinction event
The Holocene Extinction
an example of mutualism.
Humans and intestinal bacteria
What is natural selection?
The process where organisms with favorable variations survive and reproduce
A spore formed from genetic info of two different organisms
zygospore
Growth, maintenance, and repair of somatic cells
the functions of mitosis
How does artificial selection differ from natural selection?
It is guided by humans to breed desired traits
Name two human activities that contribute to extinction.
Habitat destruction, hunting, climate change, pollution
the term for two species living in direct contact
Symbiosis
refers to the process of one species evolving into another over time
Speciation
An allele that must be present in two copies to be expressed
a recessive allele
A segment of DNA that codes for a protein
A gene
Inbreeding and loss of genetic diversity
risks of artificial selection
What does it mean if a species is "extirpated"?
It no longer exists in a particular region, but is not globally extinct
Why are specialists more vulnerable to extinction?
They rely on specific environments and can't adapt easily
What is a diversity index and what does it indicate?
It's a ratio of different species to total organisms in an area; high index = healthy ecosystem
Requires a mate; slower reproduction
disadvantages of sexual reproduction
What is the purpose of "crossing over" in meiosis?
Increases genetic variation in gametes
Give an example of artificial selection in agriculture.
Breeding wheat to grow in cold climates
Species like grizzlies or wolves that show the health of an ecosystem—disappear first when ecosystems are damaged
Indicator species