Chapter 16 - Ecosystems and Gaia

Question 1

Ecology

Answer 1

When nutrient cycle is complete, solar energy originally captured by plants turns into heat
Ecosystems remain dynamic, follow long natural cycles, and evolve slowly compared to human time scales
The more species it has, the more efficiently it can harness solar energy because each species has diff way of using light, nutrients, and water

Question 2

Food webs

Answer 2

Energy and material flow

Question 3

Photosynthesis

Answer 3

Plants use solar energy to make organic chemicals
Half of energy used by plants to meet own needs, and rest turned into biomass

Question 4

Biomass

Answer 4

Body mass

Question 5

Herbivores

Answer 5

eat plants to supply energy and maintain bodies

Question 6

Carnivores

Answer 6

Eat herbivores, second order carnivores eat other carnivores
At each stage only 10-20% of food energy is converted to body tissue and rest is lost as heat
Number of animals that can be supported decreases with each level of food chain

Question 7

Waste and dead organic matter

Answer 7

Produced at each level, feed decomposer organisms such as bacteria and fungi

Question 8

Bacteria and fungi

Answer 8

Break down organic molecules into simple chemicals which can be used again as plant nutrients

Question 9

Gaia

Answer 9

Planet is a self-organizing, evolving whole
Named after Greek Goddess of the Earth
Atmosphere protects us from harmful ultraviolet radiation, product of living organisms

Question 10

Greenhouse effect

Answer 10

Over last few billion years, energy output of sun rose 25%. We should have been cooked but temp of earth remained constant; temperature regulation by cooperative interaction of species is possible