Unit 3B: Juncos - Terms and Definitions

5 Conditions of Evolution

1. Natural selection

2. Mutation

3. Gene flow

4. Genetic drift

5. Nonrandom mating

Gene Flow

migration of organisms in and out of a population. can result in different traits being spread to other areas

Nonrandom Mating

selecting a mate based off of a particular physical feature

Genetic Drift

chance event changes how frequently a trait appears

Bottleneck Effect

natural disaster or human interference leaves only a few survivors to recolonize an area, causes less genetic variation

Founder Effect

few individuals separate from main population and colonize a new area, reduces genetic variation

Divergent Evolution

when a related species becomes different over time, usually due to living in different types of environments

Convergent Evolution

unrelated species grow similar features over time usually because they live in similar types of environments

Coevolution

two different species evolve in response to change in each other, organisms have close relationship

Flight Initiation Distance

aka FID, the distance from the human at which the bird launches into flight

central nervous system (CNS)

includes brain and spinal cord

peripheral nervous system

includes nerves and neurons

Motor division

carries messages from CNS to muscles, glands, and internal organs

Sensory Division

carries messages from sensor/internal organs to CNS

Autonomic Nervous System

carries messages to organs and glands, responsible for involuntary movement

Somatic Nervous system

carries messages to skeletal muscles, responsible for voluntary movement

Sympathetic division

prepares for emergency situations or ‘fight or flight’

Parasympathetic nervous system

controls body during non-emergencies ‘rest and digest’