Lecture: #15 ([Mating systems +] Neurons, brains, and our connection to the external world)

Question 1

Mating systems

Pologomy

Answer 1

• one individual of one sex and multiple individuals of the opposite sex
• Highly dimorphic
• We see directional selection for a feature each sex prefers

types include: Polygyny and Polyandry

Question 2

Mating systems —Pologomy

Polygyny

Answer 2

• One male mates with multiple females; many females chose the same male
• The females almost all mate so there is low variance in their reproductive success
• Lots of males don’t get selected at all, have no reproductive success.

Question 3

Mating systems —Pologomy

Polyandry

Answer 3

• One female bonds with multiple males; only certain females will be selected and a lot of them won’t be
• It is very rare because females tend to make more of the upfront investment

Question 4

Mating systems

Monogamy

Answer 4

• Partners form an exclusive intimate relationship.
• May or may not involve a strong emotional bond.
• Typically equal parental investment by both partners.
• Low variance in reproductive success among individuals.
• Often seen in species with a 50/50 sex ratio.
• Monomorphic: similar physical appearance between males and females (due to relaxed selection pressure).

Question 5

Sexual dimorphism:

Answer 5

the difference in body shape or appearance or size between biological males and biological females

Question 6

Sexually monomorphic:

Answer 6

when males and females of the same species look the same and can only be distinguished sexually by their genitalia

Question 7

Our bodies use two main systems to respond to stimuli and coordinate information:

Answer 7

• The endocrine system (uses hormones as chemical messengers)
• The nervous system (Relies on electrical signals transmitted through neurons)

Question 8

Sensory neurons:

Answer 8

act as receptors, detecting sensory information from the environment. They convert these stimuli into electrical signals and transmit them to the central nervous system (CNS)

Question 9

Motor neurons:

Answer 9

receive signals from the CNS and carry instructions to your muscles, resulting in movements like running, jumping, or adjusting posture. They also are responsible for controlling certain glands

Question 10

Parts of a Neuron:

Cell body (Soma):

Answer 10

Contains the nucleus (with the DNA) and other essential parts, like the brain of the neuron.

Question 11

Parts of a Neuron:

Dendrites

Answer 11

These are like branches that reach out from the cell body and receive signals from other neurons.

Question 12

Parts of a Neuron:

Axon:

Answer 12

a long, thin fiber that carries signals away from the cell body to other neurons or muscles.

Question 13

Parts of a Neuron:

Myelin sheath:

Answer 13

fatty layer that insulates the axon, helping the signal travel faster and further.

Question 14

Parts of a Neuron:

Nodes of Ranvier:

Answer 14

small gaps in the Myelin sheath that allow the signal to jump, making transmission faster.

Question 15

Parts of a Neuron:

Terminal buttons:

Answer 15

At the end of the axon and connect with dendrites of other neurons, allowing the signal to be passed on.

Question 16

Action potential (stage names)

Answer 16

• Resting Stage:
• Depolarization:
• Repolarization:
• Undershoot:
• Return to Resting State:

Question 17

Glial cells

Answer 17

another important type of cell in the nervous system.

Although they don’t send information directly like neurons, they play crucial roles:
* They wrap nerve fibers (axons) in a fatty sheath called myelin, which helps signals travel faster and more efficiently.
* They help form connections between neurons, like building bridges for communication.
* They provide essential nutrients to keep neurons functioning properly.