EXAM 5 Flashcards

Question

Predator-prey affect each other in cycles: Availability of **\_\_\_\_** ⇒ **\_\_\_\_\_\_\_\_** predators ⇒ **\_\_\_\_\_\_\_\_** prey ⇒**\_\_\_\_\_\_\_\_** predators

Answer 1

Predator-prey affect each other in cycles: Availability of **prey** ⇒ **increase** predators ⇒ **decrease** prey ⇒**decrease** predators

Answer 2

Parasitism involves a **parasite** living on or in a **host** **organism**, **feeding** on it and **weakening** it but generally not **killing** it. Examples: **bacterium** causing Lyme disease, some **fungi**, intestinal **worms**, **ticks**, and some **protists**

Answer 3

**Competition** describes the interaction among individuals who attempt to utilize a **shared** **resource** that is limited relative to the **demand** for it, and **intensifies** as populations grow near **carrying** **capacity**.

Answer 4

**_Competition_** may be divided into two groups: **_Interspecific_** **_competition_** is between individuals of different species **_Intraspecific_** **_competition_** is between individuals of the same species

Answer 5

The size of a population at any given time is the result of complex interactions between **interspecific** and **intraspecific** **competition**.

Answer 6

**Survivorship** **in** **Populations** describes the pattern of survival in a population **Life tables** track groups of organisms born at the same time throughout their life span and can generate **Survivorship Curves**.

Answer 7

late loss constant loss early loss

Answer 8

**Late** loss curves are seen in many animals with **few** **offspring** that receive substantial **parental** **care**. examples: **humans** and many large **mammals**

Answer 9

**Constant loss** curves are an approximate straight line, indicating an equal chance of **dying at any age** example: some **bird** species

Answer 10

**Early loss curves** show high early mortality as **most** **offspring** fail to become established. examples: most **invertebrates** and **fish**

Answer 11

_Change in Human Populations_ Human Population Continues to **Grow Rapidly** Technological Advances Have Increased Earth’s **Carrying Capacity** Demographic **Transition** Helps **Stabilize** Populations Population Growth Is **Unevenly** Distributed The **Current Age Structure** of a Population Predicts Its **Future Growth** Fertility in Europe Is **Below Replacement** Level The United States Populations Is **Growing Rapidly**

Answer 12

demography

Answer 13

Demographers track **population** **changes** in different **countries** and **regions**.

Answer 14

**Demographic** **data** are used to **formulate** **policies** in public health, housing, education, employment, immigration, and environmental protection.

Answer 15

Over the **last** **decade**, the rate of human population growth seems to be **stabilizing**, with 75-80 million people added per year, indicating that we may be entering the **final** **bend** of the **s-curve**.

Answer 16

Several technological **revolutions** have greatly influenced the human ability to make **resources** available: **technical** & **cultural** **agricultural** **industrial**-**medical**

Answer 17

**Technical** & **cultural** revolution occurred in **primitive** humans. The invention of **tools** and **weapons** increased food availability, and the discovery of **fire** and creation of **shelters** and **clothing** increased their **habitable** **range**.

Answer 18

Agricultural revolution occurred beginning c. **8000 B.C.** when **animals** and **plants** were domesticated.

Answer 19

The **industrial**-**medical** revolution occurred beginning **mid-18th** century. It allowed **fewer** people to produce **more** food and **decreased** the death rate from **infectious** **disease.** This resulted in an **initial** **rise** in population, which then stabilized due to a later **decrease** in **birth** **rates**.

Answer 20

demographic transition

Answer 21

Declining birth rates associated with demographic transition result from many factors: better **education** increased access to **contraceptives** shift of populations to **cities** more **women** working **outside** the home

Answer 22

When the adults of a population have just enough children to replace themselves, the situation is called **replacement-level fertility (RLF).** Because not all children **survive** to **maturity**, **RLF** is slightly higher than **2.**

Answer 23

Many developing countries still have **rapidly** **growing** populations: – birth rates **vastly** **exceed** death rates – Children aid in **family** **income** – Limited access to **contraception** – Even if dropped to RFL, countries like China will continue growing due to **amount** of **young** **people**.

Answer 24

Population Age Structure: – **Distribution** according to age groups – The shape below the peak reveals if the population is **expanding**, **stable**, or **shrinking**

Answer 25

In an age structure that is pyramid-shaped, the population is **expanding** and **above** RLF. example: **Mexico**

Answer 26

In an age structure that has relatively straight or **symmetrical** sides, the population is **stable** and **at** RLF. example: **Sweden**

Answer 27

In an age structure that has a narrow base, the population is **shrinking** and **below** RLF. example: **Italy**

Answer 28

Even if developing countries were to achieve RLF **immediately**, their population increases would continue for **decades**.

Answer 29

U.S. population is fastest growing of all industrial nations: U.S. fertility rate is only approx. **2.0**, **below** RLF However, **immigration** is adding people rapidly and **survivorship** remains higher than in other nations

Answer 30

Growth of the U.S. has serious implications for the environment of the U.S. and the Earth: Americans consume **far more resources** and produce **far more pollution** than the global average The **ecological** **footprint** is more than **2.5** times greater for U.S. residents than the global average

Answer 31

**Neurons** (nerve cells) must perform four specialized functions: – **Receive** information – **Integrate** information – **Conduct** **signals** over distances – **Transmit** **signals** to other neurons, tissues, or organs

Answer 32

Typical neurons have four distinct structural regions * *dendrites** * *cell** **body** * *axon** * *synaptic** **terminals**

Answer 33

**Dendrites** are branched cell body extensions that **receive** **information** from surrounding neurons and sensory receptors.

Answer 34

The cell body **integrates** incoming information from **dendrites**; if incoming signals are **positive** enough, an **action** **potential** (electrical output signal) forms.

Answer 35

The **axon** conducts electrical signals to the **synaptic** **terminal**, is often covered in **myelin** to speed electric transmission, and is often **bundled** **together** to form nerves.

Answer 36

The **synaptic** **terminal** is the branched endings of axons. Most contain **neurotransmitters**, specific chemicals released under the stimulus of an action potential. Forms **synapses** with other cells - the site at which the neuron communicates with other **cells**, **tissues**, or **organs**.

Answer 37

Neural activity occurs when **neurons** produce **electrical** **voltages** across their **membranes**.

Answer 38

Most neurons have a negative resting potential: – Describes the resting **neuron** **membrane** **potential** – Ranges from **-40** to **-90** millivolts (mV) – Negative value indicates that the **cell** **interior** is more negative than the **exterior**

Answer 39

If the neuron membrane potential becomes less negative, reaching a **threshold** **value**, the neuron will generate an **action** **potential**.

Answer 40

**Action** **potential** is when the neuron membrane potential rises rapidly to +50 mV, then returns to **resting** **potential**. The action potential signal flows down **axons** to **synaptic** **terminals**, where cell communication occurs.

Answer 41

Neurons communicate at **synapses**. * The **presynaptic** neuron transmits a signal by releasing **neurotransmitter** molecules from **vesicles** into the **synaptic** gap. * The **postsynaptic** neuron has specialized **receptor** molecules which bind to the **neurotransmitter** and cause **changes** in the cell.

Answer 42

When **postsynaptic** neuron receptors bind to neurotransmitters, specific **ion** **channels** open and allow ion flow across the cell membrane, which causes a brief change in membrane potential (**postsynaptic** **potential,** or **PSP**).

Answer 43

**Excitatory** postsynaptic potentials (**EPSPs**) – Make the neuron **less** negative inside – The membrane potential gets **closer to** threshold potential – And is **more** likely to form an action potential – Can occur when **Na+** **channels** open, allowing **Na+** into the cell

Answer 44

**Inhibitory** postsynaptic potentials (**IPSPs**) —Make the neuron **more** negative inside —The membrane potential gets **further** **from** threshold potential —And is **less** likely to form an action potential —Can occur when **K+ channels** open, allowing **K+ out** of the cell

Answer 45

Individually, PSPs are weak and cannot stimulate an **action** **potential**. **Dendrites** & a **cell** **body** receive many EPSPs and IPSPs. **Summation** of PSPs occurs – if threshold is reached, an **action** **potential** forms.

Answer 46

Information processing requires four basic operations: **Determine** **type** of stimulus **Signal** **intensity** of stimulus **Integrate** information (**convergence**) **Direct** the response (**divergence**)

Answer 47

Nervous systems determine the type of stimulus based on **wiring** **patterns** in the brain - **specific** parts of the brain perceive **specific** **senses** when stimulated.

Answer 48

Stimulus intensity is coded by the frequency of **action** **potentials** and the **number** of **neurons** that are involved.

Answer 49

Neurons **integrate** information from many sources and process through **convergence**: **many** neurons funnel their signals to **fewer** neurons, **summation** occurs in these neurons and appropriate **responses** are formed.

Answer 50

Neurons initiate and direct complex responses via **divergence**: a few **decision**-**making** neurons stimulate **many** neurons that control **muscles** and **glands**.

Answer 51

Most neural pathways contain four elements: – **Sensory** neurons – **Association** neurons – **Motor** neutrons – **Effectors**

Answer 52

**Sensory** **neurons** receive information from the internal or external environment.

Answer 53

**Association** **neurons** integrate information from many different sources and activate motor neurons.

Answer 54

**Motor** **neurons** receive instructions from association neurons and activate muscles or glands.

Answer 55

**Effectors** are muscles or glands that perform the desired response.

Answer 56

**Reflex**: an involuntary movement of a body part in response to a stimulus; most follow **standard** neural pathways.

Answer 57

Radially symmetric animals have a **nerve** **net** (a diffuse network of neurons that interconnect ganglia) and lack a **brain.**

Answer 58

Bilaterally symmetric animals have a **centralized** nervous system; **cell** **bodies** tend to be clustered in the **head** **region** (cephalization) and along the **central** **axis**.

Answer 59

The nervous system of **bilateral** animals is divided into two parts: the **Central** Nervous System (**brain** & **spinal** **cord**) the **Peripheral** Nervous System (nerves that **connect** the CNS to the **rest of the body**)

Answer 60

The PNS consists of peripheral nerves: **motor** and **sensory** neurons.

Answer 61

The motor portion of the **PNS** is divided into two parts: the **somatic** nervous system controls **voluntary** motion, the **autonomic** nervous system controls **involuntary** responses.

Answer 62

The autonomic nervous system has two divisions: the **sympathetic** division prepares the body for fight or flight, the **parasympathetic** division dominates during rest and rumination.

Answer 63

The CNS is protected in three ways: the **skull** and **vertebral** **column** the **meninges** the **blood**-**brain** **barrier**

Answer 64

CNS Protection: The skull and vertebral column: **bony armor** The meninges: a triple layer of **connective** tissue with **cerebrospinal** fluid for cushioning The blood-brain barrier: relatively impermeable **brain** **capillaries** that prevent **microbes** and damaging **chemicals** from entering the brain

Answer 65

The spinal cord is a cable of **axons** protected by the **backbone** that transmits signals between the brain and body and is composed of **grey** **matter** & **white** **matter**.

Answer 66

**Grey** matter consists mostly of cell bodies of motor and association neurons.

Answer 67

**White** matter surrounds the **grey** matter and consists mostly of myelinated **axons** that send impulses up and down the spinal cord.

Answer 68

The **spinal** **cord** also contains neural pathways for some simple behaviors, such as **reflexes**.

Answer 69

All **vertebrate** brains develop anatomical and functional divisions: **hindbrain**, **midbrain**, **forebrain**.

Answer 70

The hindbrain includes the **medulla**, **pons**, and **cerebellum**.

Answer 71

The **medulla** (hindbrain) controls several autonomic functions, such as breathing, heart rate, and blood pressure.

Answer 72

The **pons** (hindbrain) plays a role in the transition from sleep to wakefulness, and regulates breathing rate.

Answer 73

The **cerebellum** (hindbrain) helps coordinate movements of the body.

Answer 74

The midbrain contains the **reticular** **formation**, an important **relay** and **sensory** filtering station that extends from the **medulla** into the lower regions of the **forebrain**.

Answer 75

The forebrain includes the **thalamus**, **limbic** **system**, and **cerebral** **cortex**.

Answer 76

The **thalamus** (forebrain) channels sensory information from all parts of the body to the **limbic** system and **cerebral** cortex.

Answer 77

The **limbic system** (in the forebrain) is a group of structures that produce our most basic and primitive **emotions**, **drives**, and **behaviors**.

Answer 78

The limbic system is composed of the **hypothalamus**, **amygdala**, and **hippocampus**.

Answer 79

The **hypothalamus** is a coordinating center between the nervous and endocrine systems.

Answer 80

The **amygdala** produces sensations of pleasure, fear, or sexual arousal.

Answer 81

The **hippocampus** is involved in emotional behaviors and the formation of long-term memory.

Answer 82

The **cerebral** **cortex** is the convoluted outer layer of the forebrain that is divided into two hemispheres connected by a large band of axons called the **corpus** **callosum**.

Answer 83

Each cerebral cortex hemisphere is divided into four anatomical regions: **frontal** lobe **parietal** lobe **occipital** lobe **temporal** lobe

Answer 84

Each cerebral cortex hemisphere is made of different functional areas: –**Primary** **sensory** **areas**: where sensory signals are received, impressions are formed –**Association areas**: interpret sounds and link sensory stimuli with memories –**Primary motor areas**: in the frontal lobe; stimulate motor neurons

Answer 85

The left hemisphere dominates the following brain functions: **speech** **reading** **writing** **language comprehension** **mathematical ability** **logical problem solving**

Answer 86

The right hemisphere dominates the following brain functions: **facial recognition** **spatial relationships** **artistic & musical ability** **recognition & expression of emotion**

Answer 87

**Axons** within each **optic** **tract** cross over in route to the brain, causing the left half of each visual field to be seen by the **right** cerebral hemisphere and the right half to be seen by the **left** hemisphere.

Answer 88

**Learning** occurs in two phases: **working memory**: short term memory caused by electrical or chemical changes in neural circuits **long-term memory**: involves structural changes that increase the number or effectiveness of synapses

Answer 89

The **hippocampus** is important for the transfer of working into long-term memory.

Answer 90

The **temporal** **lobes** are important in the retrieval of long-term memories, and are also involved with **memory** **recognition** of faces and objects, as well as understanding **language**.

Answer 91

**Sensory** **receptors** are cells that transduce the energy of a specific signal into an electrical signal called a **receptor** **potential**.

Answer 92

In sensory receptors, if the receptor potential is **positive** enough, an **action** **potential** forms. The **more** **positive** the receptor potential, the **higher** the possibility of action potential formation.

Answer 93

Temperature is sensed when **thermoreceptors** respond to heat or cold. Generally, both heat and cold receptors fire action potentials **spontaneously** at usual skin temperatures of about 77–91\*F. Cold receptors fire **more** **rapidly** at temperatures below 77\*F, whereas warm receptors fire **more** **rapidly** at temperatures above 91\*F. Thermoreceptors in the **brain** detect **core** body temperature and activate **homeostatic** **responses** to maintain appropriate body temperature.

Answer 94

The body contains many types of **mechano**receptors: receptors in the skin that respond to **touch**, **vibration**, or **pressure**; **stretch** receptors in many internal organs, including the intestines, stomach, urinary bladder, and muscles; and receptors in the inner ear that respond to **sound**, **gravity**, or **movement**.

Answer 95

Enclosed mechanoreceptors in skin: **Pacinian** corpuscles - **rapid** vibration, **rapid** pressure changes; **Meissner’s** corpuscles - **light** touch, **slow** vibrations; **Ruffini** corpuscles - steady **pressure**; **Merkel's** disc - steady **touch**.

Answer 96

Mechanoreceptors located in **hollow** organs, such as the stomach, intestine, rectum and urinary bladder, **signal** **fullness** by responding to stretch. Mechanoreceptors located in **joints** sense position of **limbs**. Mechanoreceptors located in **inner** ear detect **sound**.

Answer 97

The mammalian ear performs several different functions: – Perceives **sounds** – Determines direction of **gravity** – Detects the **orientation** and **movement** of the head

Answer 98

The ear converts sound waves into electrical signals

Answer 99

The **outer** **ear** captures sound waves and aids in sound source localization, and consists of 2 parts: **external ear:** collects sound waves and directs them into the skull **auditory canal:** carries sound waves to the middle ear

Answer 100

The middle ear transmits sound waves to the inner ear and consists of: **tympanic** **membrane**: the eardrum middle ear bones (**hammer**, **anvil**, and **stirrup**): transmit sound vibrations to inner ear **auditory** **tube**: equalizes air pressure between the middle ear and atmosphere

Answer 101

The inner ear converts **vibrations** from sound waves into **electrical** **signals** and consists of: **►cochlea** - spiral, fluid-filled tubes: the middle ear bones transfer sound energy into it by vibrating the **oval** **window** **membrane** **►vestibular** **system:** involved in balance.

Answer 102

Sound is converted into electrical signals in the cochlea, which has three fluid-filled compartments containing: the **basilar** membrane, the **tectorial** membrane, and **hair cell mechanoreceptors**.

Answer 103

Mechanism of cochlear function: sound waves are transmitted into the cochlea by **middle** **ear** **bone** vibrations; vibrations produce **fluid** **movement** that cause the **basilar** **membrane** to vibrate; basilar membrane vibrations cause **hair** **cells** to bend against the **tectorial** **membrane**; **receptor** potentials are formed, and **action** potentials are sent to the brain.

Answer 104

Perception of Sound **Larger** sound vibrations bend hair cells more, which is perceived as **louder** sounds (very **loud** or **prolonged** sounds can damage hair cells). Different parts of the **basilar** **membrane** vibrate at different **frequencies** based on sound wave characteristics, allowing for perception of different **pitches**.

Answer 105

The **vestibular** **apparatus**, in the inner ear, detects gravity and the orientation and movement of the head.

Answer 106

The vestibular apparatus is a fluid-filled tube embedded in the bones of the skull, consisting of the **vestibule** and the **semicircular** **canals**. The vestibule contains the **utricle** and **saccule**, which contain a cluster of **hair** **cells** and detect the direction of gravity and the orientation of the head.

Answer 107

All forms of vision use **photoreceptors** - cells that contain **photopigments** that absorb light, which produces chemical changes. When **photopigments** change, **receptor** **potentials** form.

Answer 108

Arthropods utilize compound eyes made of many individual light-sensitive subunits called **ommatidia**. Each **ommatidium** forms a small part of a larger image, and each image part is pieced together to form a grainy **visual** **mosaic**.

Answer 109

Mammal eyes have three major tissue layers: **Sclera**: white outer layer; tough **connective** tissue **Choroid**: dark middle layer that **absorbs** stray light; has rich blood supply **Retina**: delicate inner layer; multilayered sheet of **photoreceptors** and **neurons**

Answer 110

In the mammalian eye, light encounters the following structures before it is transduced: **►Cornea**: **transparent** covering over front of eyeball **►Aqueous** **humor**: watery fluid that **nourishes** lens and cornea **►Iris**: pigmented ring of **muscle** that controls amount of light entering eye

Answer 111

Mammalian eye structures: **Pupil**: opening in the center of the **iris** **Lens**: transparent **protein** structure that bends light **Vitreous** **humor**: jelly-like fluid; that **maintains** eye shape **Retina**: multilayered sheet of **photoreceptors**

Answer 112

Muscles attached to the **adjustable** **lens** of the mammalian eye can contract and change the shape of the lens which allows images to be focused on the **fovea** of the **retina** when looking at objects at different distances. If the eyeball is too **long**, the image is focused in front of the retina, which results in **nearsightedness**. If the eyeball is too **short**, the image is focused behind the retina which results in **farsightedness**.

Answer 113

Light striking the retina is captured by **rods** **and** **cones** – photoreceptors at the rear of the retina – that transduce light stimuli, forming **receptor** potentials. **Signal**-**processing** neurons process receptor potentials and pass forward impulses. **Ganglion** **cells** at the front of the retina carry **action** **potentials** to brain along optic nerve.

Answer 114

Each mammal eye has a **blind** **spot** where the **optic** **nerve** connects to the eyeball which lacks **photoreceptors**, so images disappear when light passes over this spot.

Answer 115

**Cones** are concentrated in the **fovea**, require relatively bright light to function, and allow for **color** **vision** by detecting red, green, and blue light wavelengths. **Rods** are concentrated in the **periphery** of the eyeball, perceive light **intensities** (shades of grey) and are responsible for vision in **dim light**.

Answer 116

**Chemoreceptors** detect the presence of **chemicals** in fluids: * *smell**: detects airborne molecules, * *taste**: detects molecules dissolved in water or saliva.

Answer 117

**Olfactory** receptors, located in the upper nasal cavity, have hair-like **dendrites** that protrude into a **mucus** layer. Odorous molecules in air dissolve in nasal cavity **mucus** and bind to **receptors** on olfactory **dendrites**; **receptor** **potentials** are formed and sent to brain.

Answer 118

The tongue bears about **10,000** taste buds in bumpy **papillae**. Each taste bud contains 60-80 taste **receptor** **cells**. Taste receptor **microvilli** project out a taste **pore**. Dissolved chemicals enter the **pore** and bind to **receptors** on **microvilli**. **Receptor** **potentials** form and are sent to brain.

Answer 119

Taste receptors allow the perception of **sweet**, **sour**, **salty**, **bitter**, and **umami** flavors.

Answer 120

Pain is the perception of **tissue** **damage**. Pain receptors (**nociceptors**) respond to two chemical stimuli: **potassium** **ions**, and **bradykinin**, which is formed from enzymes released from damaged tissue.

Answer 121

neurons Receive information Integrate information Conduct signals over distances Transmit signals to other neurons, tissues, or organs

Answer 122

**resting** **rising** - stimulation **peak** - sodium ions entered and brought potential to around +30mV **falling** - potassium ions diffuse out **undershoot** - potassium continues to flow out of the cell even after the membrane has fully repolarized

Answer 123

dopamine norepinephrine serotonin glutamate endorphins

Answer 124

dopamine receptors decrease

Answer 125

site at which a neuron communicates with other cells, tissues, or organs

Answer 126

increase speed of electric transmission

Answer 127

by the **frequency of action potentials** and the **number of neurons** that are involved

Answer 128

brain spinal cord

Answer 129

helps coordinate movements of the body

Answer 130

limbic system

Answer 131

frontal lobe

Answer 132

transmits signals between the brain & body grey matter - cell bodies of motor and association neurons white matter - surrounds grey, consists mostly of myelinated axons

Answer 133

motor neurons ventral horn gray matter of the spinal cord

Answer 134

relay and sensory filtering

Answer 135

working memory long-term memory

Answer 136

large band of axons that divides the two hemispheres of the cerebral cortex

Answer 137

warmer - yellow/red

Answer 138

touch - mechanoreceptors vision - photoreceptors hearing - mechanoreceptors taste - chemoreceptors

Answer 139

cones rods

Answer 140

area of concentration of cones

Answer 141

nociceptors respond to potassium ions or bradykinin

Answer 142

maximum rate at which population can increase in optimal conditions.

Answer 143

limits set by the living and non-living environments (availability of food, space, competition, interactions, natural events)

Answer 144

growth rate = birth rate - death rate

Answer 145

a population continuously grows at a fixed percentage of its size at the beginning of each time period J-curve

Answer 146

the maximum number sustainable by their environment turns to S-curve

Answer 147

relationship between biotic potential and environmental resistance

Answer 148

cyanobacteria, lemming

Answer 149

– Climate and weather, – Hurricanes, droughts, floods, fire – Pesticide use, pollutant release, – Overhunting – Specially short-lived species are affected – Boom-and bust population

Answer 150

– Predation – Parasitism – Competition

Answer 151

promote diversity

Answer 152

– Interspecific competition is between individuals of different species – Intraspecific competition is between individuals of the same species

Answer 153

late loss - humans, large mammals constant loss - birds early loss - most invertebrates, fish

Answer 154

limited access to contraceptives birth rates vastly exceed death rates children aid in family income

Answer 155

population is expanding and above RLF

Answer 156

3 to 4 times as much

Answer 157

rapid immigration and high survivorship