A4.1 Evolution and speciation Flashcards
define evolution
change in the heritable characteristics of a population over time.
Distinguish between heritable and acquired characteristics.
Heritable Characteristics: Traits passed from parents to children through genes. Examples: eye color, height, or hair type.
Acquired Characteristics: Traits developed during life due to experiences or the environment. They cannot be passed to children. Examples: a scar, dyed hair, or learning to play the piano.
Main Difference: Heritable traits come from DNA; acquired traits come from life experiences.
Define selective breeding and artificial selection.
both mean the same thing the process of humans choosing plants or animals with desirable traits to breed together and produce offspring with more of those desirable traits.
List reasons why humans have selectively bred domesticated animals and crop plants.
**Better Traits: **Selective breeding helps improve useful traits like size, productivity, and disease resistance in animals and crops.
More Food: It leads to better crops and animals, which means more food for everyone.
**More Money: **Farmers can earn more by breeding animals and plants that give better products, like milk, meat, or wool.
**Less Disease: **Breeding for disease resistance reduces the risk of losing crops or animals and lowers the need for chemicals.
Fits the Environment: Plants and animals can be bred to suit local conditions, like climate or soil, making farming easier and more efficient.
Outline how selective breeding can lead to rapid evolutionary change..
Selective breeding can cause quick changes in a species by choosing animals or plants with the best traits to reproduce. Over time, these traits become more common in the population, leading to noticeable changes, like bigger animals or better crops.
Explain an example of artificial selection in a crop plant.
Farmers have selectively bred corn plants over generations to produce larger ears of corn with more kernels. They chose the plants with the best traits, like bigger ears and better yield, to reproduce. Over time, this has led to the development of modern corn, which has much larger ears and higher productivity than the wild ancestors of corn.
Explain an example of artificial selection in a domestic animal.
Humans have selectively bred dogs for specific traits, like size, coat type, or behavior. For example, the border collie was bred for intelligence and herding ability, while the bulldog was bred for its muscular build and and remain calm. By choosing dogs with the desired traits to reproduce, over many generations, these traits became more common in each breed.
Define homologous structure
Body parts of different organisms that are similar in structure but different in function
List examples of different types of homologous structures at different levels of biological organization.
Molecular Level:
Proteins: Some proteins, like cytochrome c (involved in energy production), are similar in many species, such as humans and yeast. This suggests that these species share a common ancestor.
Cellular Level:
Mitochondria: The mitochondria (energy factories in cells) are similar in plants, animals, and fungi, showing that they likely evolved from a common ancestor.
Tissue Level:
Muscle Tissue: The structure of muscle cells is similar in different animals, like humans and frogs, even though the muscles might do different jobs.
Organ Level:
Limbs: The bones in the forelimbs of humans, bats, whales, and cats are similar, even though they have different functions like walking, flying, or swimming. This shows a common ancestor.
Organismal Level:
Body Plans: Vertebrates (like mammals, birds, and reptiles) all have similar skeletal structures, such as a backbone, which shows they share a common origin.
Define pentadactyl limb.
a limb with five digits, such as fingers or toes
List the bone structures present in the pentadactyl limb (specific names of bones are not required).
Upper limb bone: One long bone in the upper section (like the humerus in an arm or femur in a leg).
Lower limb bones: Two long bones in the middle section (like the radius and ulna in the forearm).
Hand/foot bones: A collection of smaller bones in the lower section including carpals (wrist bones), metacarpals (palm bones), and phalanges (finger bones)
Define divergent evolution.
when a single species splits into two or more different species over time, usually because they adapt to different environments or ways of life..
Define analogous structure.
a body part that works in a similar way in different species, but do not have similar structure or evolved from common ancestor
State an example of an analogous structure found in two species.
the wings of a bird and the wings of a butterfly; both are used for flight but have evolved independently from different ancestors, meaning their structures are different despite performing the same function.
Outline how convergent evolution results in analogous structures.
Convergent evolution happens when unrelated species evolve similar traits because they live in similar environments or face similar challenges. This results in analogous structures, which look or function similarly but do not come from a shared ancestor.
