Unit 5 (Ecology- Biotic Factors)🧡

Question 1

What is a Habitat?

Answer 1

The physical location occupied by a species.

Question 2

What is a Niche?

Answer 2

This refers to the total use of biotic and abiotic resources by a species. (Way of life)

Question 3

What is the Interspecific Competition for Resources?

Answer 3

This refers to when multiple species have overlapping niches and have to compete for the same resource.

Question 4

How does Natural Selection interact with the Interspecific Competition for Resources phenomenon?

Answer 4

Natural selection makes it so that niches rarely overlap. Animals that don’t have to compete for a resource tend to survive longer.

Question 5

What are the two possible results from interspecific resource competition?

Answer 5

1. Resource Partitioning
2. Extinction

Question 6

What is Resource Partitioning?

Answer 6

The evolution of one or both species away from the niche overlap.

Question 7

What are the two kinds of resource partitioning?

Answer 7

1. Morphological (character displacement-physical change)
2. Behavioral (ex. forage at different times)

Question 8

What is the Competition Exclusion Principle?

Answer 8

No two species can STABLY occupy identical niches.

Question 9

List three predator avoidance strategies plants have adopted.

Answer 9

1. Trichomes
2. Toxicity
3. Mimicry

Question 10

What are Trichomes?

Answer 10

Thorns, Spines, or spikey “fuzz.”

Question 11

What does it mean to be a 2nd compound?

Answer 11

A molecule that is toxic to predators but has no metabolic function in a plant. (It exists to be a deterrent and that’s it.)

Question 12

What are some physical and chemical predator avoidance strategies animals have adopted?

Answer 12

-Spines
-Footspeed
-Flight
-Size
-Venom/Toxin
-Coloration/Cryptic
-Aposematic (warning colors)
-Mimicry
(you don’t need to memorize-just understand)

Question 13

What does it mean for an animal to be Cryptic?

Answer 13

This is a form of camouflage an animal may adopt in order to appear like another organism.
(ex. Stick Bug)

Question 14

What does it mean for an animal to be Aposematic?

Answer 14

This is a predator deterrent in which the animal has evolved bright colors to indicate danger-usually poison.
(Ex. Poison Dart Frogs)

Question 15

What does it mean for an animal to engage in Mimicry?

Answer 15

They have evolved to immitate something in their enviornment.

Question 16

What is Batesian Mimicry?
What is Mullerian Mimicry?

Answer 16

1. When a harmless species mimics a dangerous species.
2. When two or more unrelated and dangerous creatures resemble each other.

Question 17

What are some behavioral predator avoidance strategies done by animals?

Answer 17

1. Group Living
2. Nocturnal
3. Fossorial
4. Playing Dead
5. Aggressive Mimicry
   (not memorize-just understand)

Question 18

What are the two main benefits of Group Living?

Answer 18

1. Provides more eyes (to see danger)
2. Enables Altruistic Behavior

Question 19

What is an example of Altruistic Behavior between animals that live together?

Answer 19

Prairie Dogs make warning calls to alert of hawks.

Question 20

What does it mean for an animal to be Fossorial?

Answer 20

This means that they burrow underground.

Question 21

What is a Keystone Species?

Answer 21

This is a species that is essential in maintaining biodiversity in an ecosystem.
(ex. Sea Star, Otters)

Question 22

What happens if you remove a sea star from a very biodiverse tidepool?

Answer 22

Starfish keep mussel populations intact, so without starfish mussels out competes all the other species, driving them all to extinction.

Question 23

What happens if you remove Otters from their natural habitat?

Answer 23

Otters keep urchin populations intact, so without otters sea urchin population grows and that declines giant kelp population, driving them all to extinction.

Question 24

How does one identify a keystone species?

Answer 24

You can’t unless you remove the species from it’s environment and watch what happens.

Question 25

What is Symbiosis? What are the two types?

Answer 25

A cooperative relationship between species.
1. Mutualism
2. Commensalism

Question 26

What is the difference between Mutualism and Commensalism?

Answer 26

-Mutualism is when both species benefits (ex. bees and plants)
-Commensalism is when one species benefits and the other one is neutral. (ex. cattle egrets and cattle)

Question 27

What are two examples of Commensalism?

Answer 27

1. Cattle egrets and cattle
2. Epiphytes (plants that live on other plants) and host trees.

Question 28

What is Parasitism?

Answer 28

This is a prolonged relationship in which the parasite derives energy from the host, to the host’s detriment.

Question 29

There are two types of parasitism, what are they? Define them both.

Answer 29

1. Endoparasite (spend the majority of life IN the host)
2. Ectoparasite (spend the majority of life ON the host)

Question 30

Due to natural selection, hosts and parasites have formed a specific relationship. Explain it.

Answer 30

Hosts evolve to resist the parasite.
Parasites evolve to not kill the host, yet still leech energy from them.
(The most successful parasites don’t kill their hosts)

Question 31

What increases the incidence of parasitism in a population?

Answer 31

An increase of population density.
(lots of ppl crowded together)