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 agesHerbivores 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)

C6H12O6 + 6O2 6CO2 + 6H2O + ATP

RESPIRATION

HOMEOSTASIS

THERMOREGULATION

TEMPERATUREREGULATION

TYPE OF HEAT PRODUCTION:Endothermy: - heat from withinEctothermy: - heat from withoutHeterothermy - employ endo and ectothermy in different situations

TEMPERATURE VARIATION:Homeothermy - constant temperaturePoikilothermy - variable temperature

TEMPERATURE REGULATION poikilotherms

TEMPERATURE REGULATION poikilotherms

Operative temperature range

TEMPERATURE REGULATION poikilotherms

Acclimatization

Lizards and snakes: body temperature varies only 4-5oC/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

Fecundity

Reproductive tradeoffs

Reproductive tradeoffs

Reproductive tradeoffs

Reproductive tradeoffs

r and K strategists

For next lecture:

• Please read Chapter 9, 10, 11, 12

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