CCA Semester 2 Flashcards
(27 cards)
Point Mutation (number)
1
Point Mutation (definition)
single gene mutation, possibly resulting in an altered phenotype
Point Mutation (example)
Saguaro - The uncommon “crested” appearance isn’t passed on, and only occurs on one arm of the cactus. This insinuates that it isn’t inherited, and it was discovered that it is likely a somatic (body) cell mutation in one or more genes that control the pattern of cell divison.
Gene Duplication (number)
2
Gene Duplication (definition)
the process of creating new DNA through cell division, possibly resulting in errors
Gene Duplication (example)
Creosotebush - The incredible drought resistance found in Creosotebush is thought to be a result of whole-genome duplication events. This means that Creosotebush has been able to generate mutations much faster while still maintaining the old traits.
Gene Transfer (number)
3
Gene Transfer (definition)
the unpredictable transfer of genetic information between parent and offspring, resulting in differences between generations
Gene Transfer (example)
Jojoba - Jojoba plants are dioecious, meaning that they have distinct male and female plants. The pollen from the male flowers is carried by wind to pollinate the seeds of the female flower. The leaves are tilted in such a way that when wind flows through them, it creates a vortex that picks up the pollen. This is also an example of co-option.
Phenotype (number)
4
Phenotype (definition)
the physical characteristics of an organism, as a result of how environment and genotype interact
Phenotype (example)
Palo Verde - Parkinsonia microphylla has evolved small leaves that allow for less evaporative water loss. Because of the small size, they can generate leaves quickly with lots of water and can shed them quickly when that water is gone. Because of their green stems, they can continue to photosynthesize even when they have no leaves.
Niche Occupation (number)
5
Niche Occupation (definition)
the process of occupying a niche (an organisms relationship with living and non-living things in it’s environment) to prevent competition
Niche Occupation (example)
Desert Ironwood - Desert Ironwoods are important nurse plants. Their low branches, wide canopies, and tall stature provide shade and protection for many plants and animals. Many birds nest in their branches, and certain plants (particularly succulent cacti) utilize the tree as a nurse plant and some only grow underneath Ironwoods.
Most Available Solution (number)
6
Most Available Solution (definition)
a species evolves the trait that is not necessarily the best response to an evolutionary problem, but what is most available in its genome
Most Available Solution (example)
Devil’s Claw - Devil’s Claw has an herbaceous stem, which is uncommon in the desert, and they cover it in a sticky mucilage to prevent evaporative water loss. They also have large, tuberous roots that can store water and nutrients. This allows for the main body of the plant to ‘die’ when conditions worsen, and then revive once they improve.
Costs & Benefits (number)
7
Costs & Benefits (definition)
whether a trait is selected for depending on the benefits or costs
Costs & Benefits (example)
Brittlebush - Brittlebush leaks a germination-inhibiting chemical when it rains that prevents nearby competitors. However, this also results in the inability to rely on nurse plants and thus brittlebush has evolved to handle extreme heat. It also can’t handle frost as a result.
Co-Option (number)
8
Co-Option (definition)
an existing trait evolves a new function
Co-Option (example)
Jointfir - Similarly to cacti, Jointfirs take their older stems and make them woodier, so they take on more of a support function while their newer stems continue to photosynthesize.
