Lecture 7: Human and animal Flashcards
Why do we need to learn about evolutionary relationships?
To understand when and how specific behaviours evolved.
Why do we need to learn about evolutionary relationships?
To understand when and how specific behaviours evolved.
How does speciation occur?
Individuals have different traits that may link to higher fitness (an adaptation), this can spread through a population via natural selection. This can result in speciation if there is geographical isolation but not because of one trait.
Describe Mayr’s biological species concept
Is the term species regularly used?
It defines what a species is; Individuals of the same species produce offspring and the offspring must be able to survive and reproduce fertile offspring.
The term is rarely used because it’s hard to classify, people often use the term taxon which is a group of organisms with common ancestry.
Describe Mayr’s biological species concept
Is the term species regularly used?
It defines what a species is; Individuals of the same species produce offspring and the offspring must be able to survive and reproduce fertile offspring.
The term is rarely used because it’s hard to classify, people often use the term taxon which is a group of organisms with common ancestry.
What do adaptations need to have?
Give an example
They must be functional and relate to higher fitness
Mouse lemurs can produce ultrasonic vocalisations that predators can’t hear.
What causes similarities and differences in traits?
Shared ancestry and different evolutionary origins.
Describe homology
It’s when organisms have similarities due to be related in the same taxon. There are three types: Morphological homology (anatomical similarities- tetrapod limbs), ontogenetic homology (developmental and embryonic similarities- human embryos have gill-slits) and molecular homology (DNA, RNA and protein similarities).
Describe homoplasy and when is it considered an analogy?
Give examples of analogies
When asked a question about this, make sure you understand the context
Similarities between organisms of different taxa that aren’t related and have evolved independently. It becomes an analogy when the similarity is a similarity in function.
For example wings of insects, bats and birds are analogous but bird and bat bones are homologous.
Marsupials and mammals, some have extremely similar morphology but aren’t closely related at all, they are more closely related to the animals in their taxa.
What is parallel evolution?
When homoplasy occurs with basic traits.
What is parallel evolution?
When homoplasy occurs with basic traits.
What do evolutionary trees tell us?
How are they made?
Evolutionary relationships, how related animals are
They are made via genetic data which helps us represent the history of evolutionary lineages.
What do the nodes of an evolutionary tree tell us?
The evolutionary relationships, aka when speciation occurred. They show the recency of common ancestry. Each node leads to two taxa and new species emerge in these lineages, this happens continuously over time. Species today are not ancestors of each other.
What are the 5 main primate taxa?
Lemurs and lorises, tasiers, new world monkeys, old world monkeys and apes and humans. The primate tree started 600 million years ago. Our closest relatives are the old world monkeys.
Can you rotate a node on an evolutionary tree?
Yes, it still shows the same thing as there is no end product.
