Final Review From Lectures 1-8 Flashcards
What is Descent with modification?
Evolution
What are the 3 Types of adaptations that exist to enable species to survive?
- Structural (Physical Features)
- Behavioural (Learned or Inherited Actions)
- Physiological (Internal and Cellular Processes)
What is Biological Fitness?
(3)
the ability of an individual:
1. to survive to reproductive age,
2. find a mate,
3. produce live, fertile offspring
(relative to that ability in other individuals in the population)
What are Homologous Structures?
(Homology)
- homologous structures are body parts that share a common ancestor, but may not necessarily perform the same function
Example:
– Forelimb bones in a human arm, horse leg, seal flipper and bat/bird wing
What is Divergent Evolution?
a process in which a trait held by a common ancestor evolves into different variations over time
What are Analogous Structures?
(Homoplasy)
What are some examples?
body parts that perform the same function, but have a different evolutionary history
(so the similarity in function NOT resulting from common ancestry)
Examples:
– Walking limbs of insects and vertebrates
– Wings of birds and bats look similar in the structure though they evolved independently
– Cranium of vertebrates and exoskeleton head of insects
– Eye of octopus and eyes in humans
– Arctic fox and ptarmigan (a bird) both under seasonal changes of colour from dark to snowy white
EXAMPLES OF NATURAL SELECTION
peppered moths
What is Sexual Selection?
- A form of non-random mating, which occurs when individuals within a population differ in their ability to attract mates
- This type of selection favours individuals with heritable traits that enhance their ability to obtain mates
- A component of natural selection in which mating success traded for survival
What is INTERSEXUAL Selection?
- Intersexual selection: mating success determined by between-sex interactions
- In other words, this type of sexual selection looks at mate choice (i.e., choice exerted by members of the opposite sex)
- More specifically, the common scenario is a female choice of males (so males must show themselves to be genetically attractive to females)
What is INTRASEXUAL Selection?
- Intrasexual selection: mating success determined by within-sex interactions
- individuals competing to obtain mates (same sex)
- For example, male-male combat over females or resources vital to mates (this often results in body size sexual dimorphism, meaning in
this case that males are much larger than females and often have adaptations to fight other males)
What is the Fundamental Asymmetry of Sex?
in most species, females invest more in their offspring than males
What are the 2 Consequences of the Fundamental Asymmetry of Sex?
- Female fitness is limited by the ability to gain resources needed to produce more eggs and healthier offspring, so females produce relatively few offspring during lifetime
- Male fitness is limited by the number of females he can mate with, and he can mate frequently because sperm are so energetically inexpensive
What is Male-Male Competition?
Males that win battles with other males monopolize matings with females in their territory
o Fights are usually won by the larger male
o Dominant males father a large number of offspring
o Males that lose fights father few or no offspring
– Thus, alleles from large successful males will increase in
frequency in the population
– If the ability to win fights and produce offspring is determined
by body size, then alleles for large body size have a significant fitness advantage
What is Sexual Dimorphism?
Sexual dimorphism refers to any trait that differs between males and females of the same species
– Weaponry
– Ornamentation and behaviour in courtship
– Body size
What is Monogamy?
(Pair Bonding)
the pattern of having one mate at a time –
one male and female have an exclusive mating relationship
(more usually called pair bonding)
What is Polygamy?
the pattern of having more than one mate at a time
– one or more males are bonded socially with one or more females
What is Polygyny?
polygamy in which one male mates with two or more females
The most common polygamous mating system in vertebrates so far studied
o Female usually provides most parental care
-For example = Male walruses grab the attention of females with loud vocalizations – males defend a large harem of females that join him underwater for copulation
elephant seals, gorillas, spotted hyenas
What is Polyandry?
polygamy in which one female mate with two or more males
The male usually provides most parental care
o Example = in the spotted sandpiper, females compete for territories in order to attract males – the female will then attempt to attract additional males for whom she will also lay eggs)
What is Polygynandry?
polygamy in which two or more males mate with two or more females
Encapsulates both polygyny and polyandry with the same species
o The numbers of males and females need not be equal
o Allows groups of males and females to live together and spend less time being concerned with mate competition
o Polygynandry may be advantageous from the female’s perspective because it causes paternity confusion, which decreases infanticide and allows her to have multiple males care for her brood
o Examples of animals that use this mating system =
red foxes, European badgers, sea spiders, ground squirrels
What is Promiscuity?
a mating system where there is no pair bonding
Females mate with multiple males, and males mate with multiple females
o Examples = Bonobos are highly promiscuous, engaging in sexual interactions more frequently than any other primate
What is a BRANCH?
Branch refers to a line representing a population through time
What is a TAXON? (Taxa)
species at tips of branch points
What are Sister Groups or Sister Taxa?
Sister groups (or sister taxa) share an immediate common ancestor at a node where their branches meet
What is POLYTOMY
Polytomy is a branch point with three or more descendants
What is a CLADE?
A clade is a group of species that includes an ancestral species and all its descendants.
What is PARAPHYLETIC?
A paraphyletic grouping consists of an ancestral species and some, but not all, of its descendants
What is POLYPHYLETIC?
A polyphyletic grouping consists of various species that lack a common ancestor
What is SYNAPOMORPHY?
A synapomorphy is a shared, derived trait common between descendants (two or more groups) and their most recent common ancestor (note – this trait is missing in more distant ancestors)
What is AUTAMORPHY?
An autapomorphy is a derived trait that is unique to a particular taxon
