#4: Animal Distribution & Ecology

Question 1

Why do similar habitats on seperate continents have different animals?

Answer 1

1. barriers to dispersal
2. Competition from established populations
3. Extinction

Question 2

Case of closely related species living in widely seperated areas are explained by:

Answer 2

1)Dispersal: one-way outward movement; active and passive
2)Vicariance: continuous habitats becomming disjunct by formation of barriers (identical to allopathy at species level)
Testable by general area cladograms of different species

Question 3

Temporary LAnd bridges

“Great American Interchange”

Answer 3

3MYA Isthmus of Panama connected North & South America; lg interchange of mammals between 2 continents
ie raccoons, foxes, bears, tapirs deer moved south

porcupines, armadillos, opposums moved north

Question 4

North America used to look alot like:

Answer 4

Africa

Question 5

Organismal level of ecology of beavers

Answer 5

adaptations for living in water, eating aquatic plants/wood, anatomy, physiology, behavior

Question 6

Population level of ecology of beavers

Answer 6

reproduce 1x/year

sensitive to drought

Question 7

Community Level of ecology of beavers

Answer 7

beaver dams create aquatic habitat
kill trees=beaver food
change competition bet trees

Question 8

Ecosystem level of ecology of beavers

Answer 8

beaver dams change course of water; alter carbon & nutrient cycling; an “ecosystem engineer”

Question 9

Niche

Answer 9

Exclusive set of all environmental conditions that permit a species to survive and multiply; subject to natural selection

Question 10

Depending on its niche volume an animal may be classified as:

Answer 10

generalist or specialist

Question 11

Population growth

Answer 11

The Exponential curve (J-curve) occurs when there is no limit to population size.
The Logistic curve (S-curve) shows the effect of a limiting factor (in this case the carrying (K) capacity of the environment).

Question 12

Niche overlap

Answer 12

Portion of resources shared by niches of 2 or more species

Question 13

Competitive exclusion

Answer 13

Reduces niche overlap

Leads to specialization/character displacement

Question 14

Predation

Answer 14

1. Too efficient of a predator (one prey) can cause it’s own extinction
2. If a predator relies on > one prey, both populations fluctuate

Question 15

Extinction

Answer 15

1. Speciation rates slightly > than extinction rates in evol history.
2. Extinction rates show peaks/valleys
3. Species with > geographic ranges have

Question 16

Rate of Extinction related to human:

Answer 16

1. destruction of habitats, climate change
2. over-fishing and poaching
3. illegal trade in exotic pets
4. spread of exotic species

Question 17

Why we should care about biodiversity loss:

Answer 17

plants produce O2
pollination by bees saves $19Billion
Medicines

Question 18

Factors responsible for loss of biodiversity

Answer 18

1. greenhouse gas emissions; climate change
2. ozone depleting chemicals-hole in ozone layer
3. Air pollutants: human health, acid rain
4. pesticides, fertilizers, medical waste: human health, animal populations, eutrophication of freshwater
5. exotic species: conversion of habitat, human health
6. habitat loss: loss of biodiversity

Question 19

Carrying capacity of earth

Answer 19

animals kept below or at carrying capacity by disease, famine, predation or weather

Question 20

Human population is growing because

Answer 20

tech and medical advances have eliminated many of the above factors

Question 21

Limits to carry capacity of earty

Answer 21

1/3 of 2Bill people alive today are malnourished

Question 22

Examples of lessons learned

Answer 22

1. Removal of coyotes (keystone predator) in TX to protect livestock, doubled rodent populations causing greater economic loss to stored grains
2. extinction of Hawaiian birds has caused extinction of native plants due to no longer being pollinated