Animal adaptations Outline: Acquisition of energy and nutrients Respiration Homeostasis Water balance Biological rhythms Readings: Chapter 7

Energy and nutrient acquisition

Detritivores

Herbivores

Types of herbivores Grazers - leaf tissue Browsers - woody tissue Granivores - seeds Frugivores - fruit Nectivores - nectar Phloem feeders - sap High cellulose (fiber), low protein Animals can’t digest cellulose (no cellulase enzymes) Need symbiotic bacteria, protozoa

Ruminants (e.g. cows, sheep, deer)

Non-ruminants (e.g. rabbits, horses)

Coprophagy = ingestion of feces E.g. Lagomorphs (rabbits, hares & pikas) E.g. Detritivores

N and food quality For herbivores, food quality increases with increasing N content In animals, C:N ~ 10:1 In plants, C:N ~ 40:1  herbivores limited by N availability –Highest in growing stems, leaves, buds –Decreases as plant ages  Herbivores usually born in spring

Carnivores

Composition of food similar to own tissues --> simple stomach --> small caecum Need to get enough food

Omnivores Feed on > 1 trophic level, e.g. plants and herbivores Diet varies with season, life cycle

Diet breadth 1.Generalists: “polyphagous” – eat >1 prey species 2.Specialists: “monophagous” – eat one prey species – or eat specific part of prey E.g. seed-eating birds Specialists are usually Short-lived (active only when food is available) Highly adapted to a specific food type (can’t use any other)

C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + ATP RESPIRATION

HOMEOSTASIS

THERMOREGULATION

TEMPERATURE REGULATION TYPE OF HEAT PRODUCTION: Endothermy: - heat from within Ectothermy: - heat from without Heterothermy - employ endo and ectothermy in different situations TEMPERATURE VARIATION: Homeothermy - constant temperature Poikilothermy - variable temperature

TEMPERATURE REGULATION poikilotherms

Operative temperature range

TEMPERATURE REGULATION poikilotherms Acclimatization

Lizards and snakes: body temperature varies only 4-5 o C/day TEMPERATURE REGULATION poikilotherms

TEMPERATURE REGULATION homeotherms

Endothermy – ectothermy tradeoffs

Endothermy tradeoff

Because of their small size (high surface: volume ratio) and their need to invest energy in growth, juvenile birds and mammals are often ectothermic, obtaining heat from their parents. Conserving energy – ectothermy for juveniles

Bears are not true hibernators; their body temperature drops only a few degrees, and they are relatively easily awakened Conserving energy – hibernation

Conserving energy – countercurrent heat exchange without with

Releasing energy – countercurrent heat exchange RETE

Adaptations to aridity and heat

Water balance in aquatic environments Freshwater organisms: hyperosmotic (water wants to move inside of organism Marine organisms: hypoosmotic (water wants to move outside of organism

Controls on activity

Human diurnal cycle

Life history strategies Outline: Types of reproduction Mating systems Sexual selection Energy and timing of reproduction Offspring Habitat selection Environmental influences Readings: Ch. 8

A simple life history Life history = schedule of birth, growth, reproduction & death

Types of reproduction Asexual or sexual Different forms of sexual reproduction

Simultaneous hermaphrodites

Sex change

Mating system Strength of bond: – Monogamy (strong) - Promiscuity (no bond) Types of bonds: – Monogamy (one-to-one) – Polygamy (one-to-many) Polygyny (one male, many females) Polyandry (one female, many males)

POLYANDRY: African Jacana

Sexual selection Intrasexual selection – male-to-male or female-to-female competition for the opportunity to mate

Sexual selection Intersexual selection – differential attractiveness of individuals

Reproduction is costly

Timing of reproduction Semelparity - reproduce once and die Iteroparous - reproduce throughout lifetime

European grasshopper, Chorthippus brunneus An iteroparous summer annual

Pigweed, Chenopodium album A semelparous summer annual

Semelparous perennials Coho salmon: a long-lived semelparous animal Dies after spawning (2-5 yrs) Overlapping generations

Bamboo Both genets and ramets are semelparous. Genets can live for 200 years before the simultaneous flowering of all ramets. Semelparous perennials

Parental investment

Fecundity

Reproductive tradeoffs

r and K strategists

For next lecture: Please read Chapter 9, 10, 11, 12 65