Lecture 1: Macroevolution and Microevolution

Question 1

Macroevolution

Answer 1

1) Large-scale changes at species and higher taxonomic levels, leading to new species. genera, and biodiversity shifts. Driven by the cumulative effects of microevolution over long periods.

2) Study of large-scale evolutionary changes that occur over long periods of time, driven by factors such as environmental change, significant mutations, convergence, rare events (biotic and abiotic), extinctions, and “failed” experiments, all within the constrains of ecological, physiological, and historical limits. Because macro-evolution involves limited data, questions in this field often need to be simplified.

Question 2

Microevolution

Answer 2

Small changes in a population due to mutations, natural selection, and gene flow, which can lead to speciation.

Question 3

Predictions for Evolutionary Processes

Answer 3

1) Microevolution: Small-scale changes within a species, constant mutations causing variations, and survival of the fittest.

2) Macroevolution: Involves large-scale, possibly time-independent evolutionary changes.

(in the context of evolutionary processes, “predictions” refer to expectations or hypotheses about how species or populations will evolve over time, based on the mechanisms of evolution)

Question 4

Aristotle’s Historical Theory

Answer 4

Hierarchical view of life (scala naturae), gradual perfection, and continuity.

Question 5

William Harvey Historical Theory

Answer 5

Proposed epigenesis, where organisms develop by adding structures in succession.

Question 6

‘Great Chain of Being’ Historical Theory

Answer 6

Idea that all life forms fit a continuous hierarchy, influenced by the preformationism and epigenesis theories.

Question 7

Meckle-Serres Law Historical Theory

Answer 7

Increasing complexity through the addition of new parts, with simpler forms preceding more complex ones in development.

Question 8

Von Bae’s Laws (general principles of embryonic development, particularly the similarity and divergence of early stages of development across different species)

Answer 8

1. General traits appear before specialized traits in embryonic development.
2. Development moves from general to specific characteristics.
3. Embryos diverge from simpler forms, rather than passing through adult stages of other species.
4. Higher animal embryos resemble embryos, not adults, of lower forms.

Question 9

Name 3 Key Evolutionary Theories

Answer 9

1) Haeckel’s Ontogeny Recapitulates Phylogeny: Development mirrors evolutionary stages.

2) Palingenesis: Development reflects ancestral traits.

3) Caenogenesis: Development introduces new traits.

Question 10

Heterochrony

Answer 10

• Evolutionary changes due to shifts in developmental timing.
• Example: Neoteny: Retention of juvenile traits in adults.

Question 11

Examples of Evolutionary Theories

Answer 11

1) Lungfish Fins: Reflect evolutionary adaptation.

2) Ambystoma: Example of neoteny in salamanders.

3) Mammalian Brain Growth: Human brains show hypermorphosis (extended growth periods).

Question 12

Summarize the concept of this lecture and what was taught.

Answer 12

1) Evolutionary changes are closely linked to developmental processes (Evo-Devo).

2) Heterochrony is a common method of evolutionary adaptation.

3) Macroevolution explores biological possibilities and limitations over immense timescales.